Upload
buidien
View
217
Download
1
Embed Size (px)
Citation preview
1
Access Network Design Access Network Design
David TipperAssociate ProfessorAssociate Professor
Department of Information Science and Telecommunications
University of PittsburghSlides 8
httpwwwsispittedu~dtipper2110htmlhttpwwwsispittedu~dtipper2110html
bull A top down network design project should follow the four steps below
Top Down Network Design Approach
ndash Conceptual Modelbull Objectives Requirements Constraints
ndash Logical Modelbull Technology network graph node location link size etc
(where algorithms are used to minimize cost)
ndash Physical Model
TELCOM 2110 2
bull Specific hardwaresoftware implementations
bull (eg wiring diagram repeater locations etc)
ndash Implementation Testing Tuning and Documentation
2
Technology Choicesbull Wireless Access Network Design
ndash Physical design is incorporated in the Logical Design ( Power level Technology Frequency etc)
bull Wired Access Network Design Root
ndash the logical layer may be partially separated from the physical design
ndash Technology Choicesndash For circuit switched voice traffic
bull STM ATM ndash constant bit rate service (CBR) MPLS CBR emulation
ndash For packet data trafficbull STM ATM SMDS X25 Frame Relay Token Ring
FIDDI Ethernet cable modem dSL wireless
21
34 5
TELCOM 2110 3
FIDDI Ethernet cable modem dSL wireless technology etc
ndash Choice depends on cost and features neededndash Given technology selection and logical design
bull create physical design (select equipment addressing wiring etc)
6
Technology Choicesbull For Wired Network Packet Data trafficbull Choice depends in part on distances
ndash Connect Pitt branch campuses and labs (Johnstown Bradford etc) to main Pitt (Jo sto ad o d etc ) to a ttcampus computer center ndashbull Options Private Line (DS-1 DS-3 OC-3 etc) Frame Relay
ATM SMDS IPSTM X25 ISDN MPLS based VPN VPLS etc
ndash Connect hostsservers in different locations of a building to campus backbonebull Ethernet Fast Ethernet Gigabit Ethernet etc
bull Need to factor in performance needs and user
TELCOM 2110 4
requirements (eg lease vs buy security etc)bull Consider LAN physical design
ndash Majority of installations today are Ethernet to the desktop ndash growing deployment of WLAN 80211 to the desktop
3
Classical Ethernet
bull IEEE 8023 Standard 1983bull Bus topology LANbull 10 Mbps
CSMACD medium accessbull CSMACD medium access control protocol
bull 10Base5 ndash coax cabling ndash 10 Mbpsndash 50-ohm coaxial cable busndash Maximum segment length 500
meters ndash extend with repeaters
bull 10Base-T cabling (1987)
TELCOM 2110 5
10Base T cabling (1987)ndash Twisted pair maximum length
100 metersndash Star topology (hub at central
point)
Ethernet Frame StructureSending adapter encapsulates IP datagram (or
other network layer protocol packet) in Ethernet frameframe
Preamble
TELCOM 2110 6
bull 7 bytes with pattern 10101010 followed by one byte with pattern 10101011
bull used to synchronize receiver sender clock rates
4
Ethernet Frame Structure
bull Addresses 6 bytesndash if adapter receives frame with matching
destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol
ndash otherwise adapter discards frame
bull Type indicates the higher layer protocol (mostly IP but others may be supported)
TELCOM 2110 7
bull CRC checked at receiver if error is detected the frame is simply dropped
CSMACD (Collision Detection)
CSMACD carrier sensing multiple access with collision dectection
adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense
ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection
bull collision detection
TELCOM 2110 8
ndash easy in wired LANs measure signal strengths compare transmitted received signals
5
CSMACD collision detection
TELCOM 2110 9
Jam Signal make sure all other transmitters are aware of collision 48 bits
Ethernet CSMACD algorithm
1 Adaptor receives datagram from net layer amp creates frame
4 If adapter detects another transmission while transmitting aborts and
2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits
3 If adapter transmits entire
sends jam signal
5 After aborting adapter enters exponential backoff after the mth
collision adapter chooses a K at random from
TELCOM 2110 10
pframe without detecting another transmission the adapter is done with frame
012hellip2m-1 Adapter waits K512 bit times and returns to Step 2
6
Ethernet Evolution
bull Ethernet Protocol so wide spread that evolution rather than replacement
bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options
bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet
bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP
Gigabit Ethernet 1 10 Gbps Ethernet
TELCOM 2110 11
ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP
Current Ethernet Options
bullBusbullTransmission from a station broadcast to all stations on the bus
bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time
L 2 Eth t S it h
TELCOM 2110 12
bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
2
Technology Choicesbull Wireless Access Network Design
ndash Physical design is incorporated in the Logical Design ( Power level Technology Frequency etc)
bull Wired Access Network Design Root
ndash the logical layer may be partially separated from the physical design
ndash Technology Choicesndash For circuit switched voice traffic
bull STM ATM ndash constant bit rate service (CBR) MPLS CBR emulation
ndash For packet data trafficbull STM ATM SMDS X25 Frame Relay Token Ring
FIDDI Ethernet cable modem dSL wireless
21
34 5
TELCOM 2110 3
FIDDI Ethernet cable modem dSL wireless technology etc
ndash Choice depends on cost and features neededndash Given technology selection and logical design
bull create physical design (select equipment addressing wiring etc)
6
Technology Choicesbull For Wired Network Packet Data trafficbull Choice depends in part on distances
ndash Connect Pitt branch campuses and labs (Johnstown Bradford etc) to main Pitt (Jo sto ad o d etc ) to a ttcampus computer center ndashbull Options Private Line (DS-1 DS-3 OC-3 etc) Frame Relay
ATM SMDS IPSTM X25 ISDN MPLS based VPN VPLS etc
ndash Connect hostsservers in different locations of a building to campus backbonebull Ethernet Fast Ethernet Gigabit Ethernet etc
bull Need to factor in performance needs and user
TELCOM 2110 4
requirements (eg lease vs buy security etc)bull Consider LAN physical design
ndash Majority of installations today are Ethernet to the desktop ndash growing deployment of WLAN 80211 to the desktop
3
Classical Ethernet
bull IEEE 8023 Standard 1983bull Bus topology LANbull 10 Mbps
CSMACD medium accessbull CSMACD medium access control protocol
bull 10Base5 ndash coax cabling ndash 10 Mbpsndash 50-ohm coaxial cable busndash Maximum segment length 500
meters ndash extend with repeaters
bull 10Base-T cabling (1987)
TELCOM 2110 5
10Base T cabling (1987)ndash Twisted pair maximum length
100 metersndash Star topology (hub at central
point)
Ethernet Frame StructureSending adapter encapsulates IP datagram (or
other network layer protocol packet) in Ethernet frameframe
Preamble
TELCOM 2110 6
bull 7 bytes with pattern 10101010 followed by one byte with pattern 10101011
bull used to synchronize receiver sender clock rates
4
Ethernet Frame Structure
bull Addresses 6 bytesndash if adapter receives frame with matching
destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol
ndash otherwise adapter discards frame
bull Type indicates the higher layer protocol (mostly IP but others may be supported)
TELCOM 2110 7
bull CRC checked at receiver if error is detected the frame is simply dropped
CSMACD (Collision Detection)
CSMACD carrier sensing multiple access with collision dectection
adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense
ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection
bull collision detection
TELCOM 2110 8
ndash easy in wired LANs measure signal strengths compare transmitted received signals
5
CSMACD collision detection
TELCOM 2110 9
Jam Signal make sure all other transmitters are aware of collision 48 bits
Ethernet CSMACD algorithm
1 Adaptor receives datagram from net layer amp creates frame
4 If adapter detects another transmission while transmitting aborts and
2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits
3 If adapter transmits entire
sends jam signal
5 After aborting adapter enters exponential backoff after the mth
collision adapter chooses a K at random from
TELCOM 2110 10
pframe without detecting another transmission the adapter is done with frame
012hellip2m-1 Adapter waits K512 bit times and returns to Step 2
6
Ethernet Evolution
bull Ethernet Protocol so wide spread that evolution rather than replacement
bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options
bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet
bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP
Gigabit Ethernet 1 10 Gbps Ethernet
TELCOM 2110 11
ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP
Current Ethernet Options
bullBusbullTransmission from a station broadcast to all stations on the bus
bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time
L 2 Eth t S it h
TELCOM 2110 12
bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
3
Classical Ethernet
bull IEEE 8023 Standard 1983bull Bus topology LANbull 10 Mbps
CSMACD medium accessbull CSMACD medium access control protocol
bull 10Base5 ndash coax cabling ndash 10 Mbpsndash 50-ohm coaxial cable busndash Maximum segment length 500
meters ndash extend with repeaters
bull 10Base-T cabling (1987)
TELCOM 2110 5
10Base T cabling (1987)ndash Twisted pair maximum length
100 metersndash Star topology (hub at central
point)
Ethernet Frame StructureSending adapter encapsulates IP datagram (or
other network layer protocol packet) in Ethernet frameframe
Preamble
TELCOM 2110 6
bull 7 bytes with pattern 10101010 followed by one byte with pattern 10101011
bull used to synchronize receiver sender clock rates
4
Ethernet Frame Structure
bull Addresses 6 bytesndash if adapter receives frame with matching
destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol
ndash otherwise adapter discards frame
bull Type indicates the higher layer protocol (mostly IP but others may be supported)
TELCOM 2110 7
bull CRC checked at receiver if error is detected the frame is simply dropped
CSMACD (Collision Detection)
CSMACD carrier sensing multiple access with collision dectection
adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense
ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection
bull collision detection
TELCOM 2110 8
ndash easy in wired LANs measure signal strengths compare transmitted received signals
5
CSMACD collision detection
TELCOM 2110 9
Jam Signal make sure all other transmitters are aware of collision 48 bits
Ethernet CSMACD algorithm
1 Adaptor receives datagram from net layer amp creates frame
4 If adapter detects another transmission while transmitting aborts and
2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits
3 If adapter transmits entire
sends jam signal
5 After aborting adapter enters exponential backoff after the mth
collision adapter chooses a K at random from
TELCOM 2110 10
pframe without detecting another transmission the adapter is done with frame
012hellip2m-1 Adapter waits K512 bit times and returns to Step 2
6
Ethernet Evolution
bull Ethernet Protocol so wide spread that evolution rather than replacement
bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options
bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet
bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP
Gigabit Ethernet 1 10 Gbps Ethernet
TELCOM 2110 11
ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP
Current Ethernet Options
bullBusbullTransmission from a station broadcast to all stations on the bus
bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time
L 2 Eth t S it h
TELCOM 2110 12
bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
4
Ethernet Frame Structure
bull Addresses 6 bytesndash if adapter receives frame with matching
destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol
ndash otherwise adapter discards frame
bull Type indicates the higher layer protocol (mostly IP but others may be supported)
TELCOM 2110 7
bull CRC checked at receiver if error is detected the frame is simply dropped
CSMACD (Collision Detection)
CSMACD carrier sensing multiple access with collision dectection
adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense
ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection
bull collision detection
TELCOM 2110 8
ndash easy in wired LANs measure signal strengths compare transmitted received signals
5
CSMACD collision detection
TELCOM 2110 9
Jam Signal make sure all other transmitters are aware of collision 48 bits
Ethernet CSMACD algorithm
1 Adaptor receives datagram from net layer amp creates frame
4 If adapter detects another transmission while transmitting aborts and
2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits
3 If adapter transmits entire
sends jam signal
5 After aborting adapter enters exponential backoff after the mth
collision adapter chooses a K at random from
TELCOM 2110 10
pframe without detecting another transmission the adapter is done with frame
012hellip2m-1 Adapter waits K512 bit times and returns to Step 2
6
Ethernet Evolution
bull Ethernet Protocol so wide spread that evolution rather than replacement
bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options
bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet
bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP
Gigabit Ethernet 1 10 Gbps Ethernet
TELCOM 2110 11
ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP
Current Ethernet Options
bullBusbullTransmission from a station broadcast to all stations on the bus
bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time
L 2 Eth t S it h
TELCOM 2110 12
bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
5
CSMACD collision detection
TELCOM 2110 9
Jam Signal make sure all other transmitters are aware of collision 48 bits
Ethernet CSMACD algorithm
1 Adaptor receives datagram from net layer amp creates frame
4 If adapter detects another transmission while transmitting aborts and
2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits
3 If adapter transmits entire
sends jam signal
5 After aborting adapter enters exponential backoff after the mth
collision adapter chooses a K at random from
TELCOM 2110 10
pframe without detecting another transmission the adapter is done with frame
012hellip2m-1 Adapter waits K512 bit times and returns to Step 2
6
Ethernet Evolution
bull Ethernet Protocol so wide spread that evolution rather than replacement
bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options
bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet
bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP
Gigabit Ethernet 1 10 Gbps Ethernet
TELCOM 2110 11
ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP
Current Ethernet Options
bullBusbullTransmission from a station broadcast to all stations on the bus
bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time
L 2 Eth t S it h
TELCOM 2110 12
bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
6
Ethernet Evolution
bull Ethernet Protocol so wide spread that evolution rather than replacement
bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options
bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet
bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP
Gigabit Ethernet 1 10 Gbps Ethernet
TELCOM 2110 11
ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP
Current Ethernet Options
bullBusbullTransmission from a station broadcast to all stations on the bus
bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time
L 2 Eth t S it h
TELCOM 2110 12
bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
7
Switch traffic isolationbull switch installation breaks subnet into LAN segments
bull switch filters packetsndash same-LAN-segment frames not usually forwarded
t th LAN tonto other LAN segmentsndash segments become separate collision domains
h b h b hub
switch
collision domain
TELCOM 2110 13
hub hub hub
collision domain collision domain
Typical Physical Topology
Often have a mix of speeds and hubsswitches in LAN
TELCOM 2110 14
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
8
Ethernet LAN Building Blocks
bull Network Interface Cardndash IO device that interfaces
computer to network ndash Frame transmission and
reception
bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN
bull Hub
TELCOM 2110 15
bull Hubndash Multicast device - broadcasts
frame to all output portsndash Star Configurationndash Data Link Layer
LAN Building Blocks
bull Media Converters ndash Connect different physical media
types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)
bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address
and Forwards valid framesndash Can bridge different speedmedia
networks bull Switch
TELCOM 2110 16
ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash
examines MAC address to determine port to forward frame too
ndash Multiple ports can handle multiple frames at a time
ndash Can do cut through switching in hardware
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
9
LAN Building Blocks
bull Layer 3 switch or Routerbull Operates at the Network Layer
(layer 3) of OSI Modelndash Uses protocol (IP) to determine
action
bull Used to connect dissimilar LANrsquosndash can covert frame from one type to
another provide security etc
bull Makes a decision to forward or drop a frame
bull Maintains routing tables that list
TELCOM 2110 17
Maintains routing tables that list connected networksndash IP amp MAC address of next relay
station
bull Does not forward broadcast frames (layer 2)
LAN Wiring
Cables are connected to network devices and the computerMost networks use a mixture of cable types
bull Coaxial cable ndash Known as Thin Net or T
base 2 or T-2
bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP
bull Plenum Cable ndash jackets are made of
nonflammable fluoro-polymers (such as Teflon)
ndash More expensive than non-plenum jackets
bull Non-plenum cable uses less expensive
TELCOM 2110 18
Five categories of UTP
bull Fiber-optic cablendash single-mode ndash multi-mode or graded-
index multi-mode
ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
10
Medium Options for Ethernet
bull Coax - 13ft + 300 per connector
bull UTP category 5 -ndash Plenum - 33ft + 100 per
connector
ndash PVC - 13ft + 100 per connector
bull Multi-mode Fiber - 35ft + 1500 per connector
TELCOM 2110 19
bull Single mode Fiber - 50ft + 1500 per connector
Wiring Standards
bull Large Number of Wiring Standards see httpwwwtiaorg
bull For example TIAEIA-568pndash Commercial Building Telecommunications
Cabling Standardbull Sets specific requirements for cable
ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and
wire in commercial environment
bull TIAEIA-568A covers 6 areas
TELCOM 2110 20
568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
11
BackboneSwitch
bull Need to connect the numerous wires (could be hundreds) to the network
Wiring ClosetPatch Panel
PC
Fiber Patch Panel
Fiber Run
UTP P Panel
Fiber Patch Panel
network
bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics
L ti
TELCOM 2110 21
Wall Jack
In conduit Wiring
UTP P Panel
Switch
bull Locationndash Accessibility amp Security
ndash Environmental concerns (heatingcooling power)
Taxonomy
bull Thus far have considered wired and wireless greenfield access design
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 22
VPN
greenfield greenfield incremental
Stage
The techniques used to design the network will depend on the classification
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
12
Virtual Networksbull Virtual Network refers to
ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo
ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)
bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers
in different technologyndash Some technology options
bull WANndash MPLSndash WDM ndash lightpath based VNs
bull MANs
TELCOM 2110 23
bull MANsndash SONET WiMAX VPLS MPLS etc
bull LANsndash Ethernet 80211
bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc
bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q
Virtual LANs (VLANs)
bull VLANsndash Group of devices on one or more physical LANrsquos that are
configured such that they are logically attached to the same wire
ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager
bull VLAN Usendash Separate out users into logical groups of workers regardless
of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more
TELCOM 2110 24
Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses
ndash Broadcast and multi-cast traffic only goes to members of VLAN
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
13
VLAN Types
bull Basic techniques for providing VLANs 1 Port Based
bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based
ndash Uses the end stations MAC address for VLAN Assignment
3 High Layer Based bull Protocol based
TELCOM 2110 25
ndash Uses protocol to determine VLAN assignment
ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN
assignment
bull Etc
VLAN Types
bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port
bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs
TELCOM 2110 26
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
14
VLAN Types
bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching
TELCOM 2110 27
VLAN Types
bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address
for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1
switch
to externalnetwork
router
VLAN ndash defined by
mail server
web server
TELCOM 2110 28
hub hub hub
f yMAC list at switch
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
15
VLAN Typesbull Higher Layer Based VLANs ndash many options
ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs
bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on
HR-VLAN etcndash General protocol policy based
TELCOM 2110 29
General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC
address subnet or higher layer info time of day etcndash Dynamic Based
bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User
can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user
Large Networks
bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left
bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets
TELCOM 2110 30
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
16
IEEE 8021Q
bull IEEE standard specifying VLAN functionality for 802 Bridged LANs
bull Supports ppndash port based MAC address based and higher layer
VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges
IEEE 802 p priority based VLAN membership
TELCOM 2110 31
ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)
bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)
bull propagation of VLAN information
IEEE 8021Q
bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in
Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of
ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet
FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field
bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs
TELCOM 2110 32
y p
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
17
IEEE 8021Q
bull IEEE 8021Q
bull Provide means for
Router
TELCOM 2110 33
campus wide VLANs
Taxonomy
Network DesignSize
Metro AccessWAN
Wired
Size
Wired Wireless
Technology
Stage
TELCOM 2110 34
Incremental greenfield greenfield VPN
Stage
The techniques used to design the network will depend on the classification
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
18
Access Network Incremental Design
bull Basically two types of Access Network Incremental Design
1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance
features reliability security etc (ie meet set of technical or business objectives)
ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)
bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)
2 Expansion
TELCOM 2110 35
pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem
connecting to a hubbackbone node on the existing infrastructure
bull Both are imbedded in whatever technology currently using
Incremental AND
to externalmail server
Consider corporate network using 100Mbs Ethernet Congestion on file server link
switch
to externalnetwork
router
Congested link
file server
TELCOM 2110 36
hub hubhub
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
19
Link Aggregation
bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch
upgrade) or Link Aggregation
bull Link Aggregation ndash Combine several independent links so it looks to the
system like one large connectionndash The idea is to create a ldquological linkrdquo made up of
several normally independent links
TELCOM 2110 37
Link Aggregation
bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines
i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo
bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches
bull Distribute traffic in bundled links based on
TELCOM 2110 38
Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39
20
Access Network Design
bull Wired Network Designndash One speed one center design
ndash Multi-speed access design
ndash Multi-center design
bull Wireless Network Designndash Point-to-Point Link Design
ndash Last hop WLAN designndash Last hop WLAN design
bull Physical Layer Considerations
bull Virtual and Incremental Design
TELCOM 2110 39