Network ArchitectureNetwork Architecture

Layout designed and constructed by:

Vicki Kertz

TOPOLOGIESTOPOLOGIES

BusBus

RingRing

StarStar

HybridHybrid

Enterprise-wide Enterprise-wide

WANWAN

BusBus

a central cable that a central cable that connects all connects all devicesdevices on a on a local-area network local-area network

RingRing

Each node is Each node is connected to the two connected to the two nearest nodes so that nearest nodes so that the entire network the entire network forms a circle.forms a circle.

StarStar

Each Each nodenode (file (file server, workstations, server, workstations, and peripherals) and peripherals) connected directly to connected directly to a central network a central network hubhub or or concentratorconcentrator

HybridsHybrids

Star-wired RingStar-wired Ring

Star-wired BusStar-wired Bus

Daisy-chainedDaisy-chained

Hierarchical Hierarchical

Enterprise -wideEnterprise -wide Backbone Networks Backbone Networks – cabling that– cabling that connects connects

the hubs, switches and routersthe hubs, switches and routers Serial Serial – simplest; two or more connected by a single – simplest; two or more connected by a single

cablecable Distributed Distributed – number of hubs connected to a series – number of hubs connected to a series

of central hubs in a hierarchyof central hubs in a hierarchy Collapsed Collapsed – a router or switch as the single central – a router or switch as the single central

connection point for multiple subnetworksconnection point for multiple subnetworks ParallelParallel – robust; more than one connection from the – robust; more than one connection from the

central router to each network segmentcentral router to each network segment

Mesh Mesh – routers interconnected with others and – routers interconnected with others and at least two pathways connecting each routerat least two pathways connecting each router

WANWAN

Peer-to-peerPeer-to-peer

RingRing

StarStar

MeshMesh

TieredTiered

Network Transport SystemsNetwork Transport Systems

The logical topology is the way that the The logical topology is the way that the signals act on the network media, or the signals act on the network media, or the way that the data passes through the way that the data passes through the network from one device to the next network from one device to the next without regard to the physical without regard to the physical interconnection of the devices. interconnection of the devices.

SwitchingSwitching Circuit -Circuit - A type of communications in which a A type of communications in which a dedicateddedicated channelchannel

(or (or circuitcircuit) is established for the duration of a transmission. ) is established for the duration of a transmission.

Message – establishes a connection between two devices, Message – establishes a connection between two devices,

transfers the info to the 2transfers the info to the 2ndnd device, then breaks the connection. device, then breaks the connection.

Packet - Refers to Packet - Refers to protocolsprotocols in which messages are divided into in which messages are divided into

packetspackets before they are sent. Each packet is then transmitted before they are sent. Each packet is then transmitted

individually and can even follow different routes to its destination. individually and can even follow different routes to its destination.

Once all the packets forming a message arrive at the destination, Once all the packets forming a message arrive at the destination,

they are recompiled into the original message. they are recompiled into the original message.

CSMA/CDCSMA/CD

Carrier Sense Multiple Access with Carrier Sense Multiple Access with Collision DetectionCollision Detection

Set of rules determining how Set of rules determining how networknetwork devicesdevices respond when two devices respond when two devices attempt to use a attempt to use a data channeldata channel simultaneously (called a simultaneously (called a collisioncollision) )

Standard Standard EthernetEthernet networks use networks use CSMA/CD CSMA/CD

Ethernet VersionsEthernet Versions

10Base2 10Base2 10Base510Base5 10BaseT10BaseT 100BaseT100BaseT 100BaseTX100BaseTX 100BaseVG100BaseVG 1000BaseX1000BaseX

10Base210Base2 The 10Base-2 standard (also called The 10Base-2 standard (also called ThinnetThinnet) uses 50 ) uses 50

ohm ohm coaxial cablecoaxial cable (RG-58 A/U) with maximum lengths of (RG-58 A/U) with maximum lengths of 185 meters.185 meters.

Ethernet over coaxial cable with a maximum distance of Ethernet over coaxial cable with a maximum distance of 185 meters. Also referred to as 185 meters. Also referred to as Thin EthernetThin Ethernet or or ThinnetThinnet or or ThinwireThinwire. .

10Base510Base5 The original cabling standard for The original cabling standard for EthernetEthernet that that

uses uses coaxial cablescoaxial cables. The name derives from the . The name derives from the fact that the maximum data transfer speed is fact that the maximum data transfer speed is 1010 MbpsMbps, it uses , it uses basebaseband transmissionband transmission, and the , and the maximum length of cables is maximum length of cables is 5500 meters. 00 meters.

10BaseT10BaseT 10 10 MbpsMbps basebandbaseband

100BaseT100BaseT A A networkingnetworking standardstandard that supports that supports

data transfer ratesdata transfer rates up to 100 up to 100 MbpsMbps (100 (100 megabits per second). 100BASE-T is based on megabits per second). 100BASE-T is based on the older the older EthernetEthernet standard. Because it is 10 standard. Because it is 10 times faster than Ethernet, it is often referred to times faster than Ethernet, it is often referred to as as Fast Ethernet.Fast Ethernet. (100BaseTX & 100BaseT4) (100BaseTX & 100BaseT4)

1000BaseT1000BaseT

A specification for Gigabit A specification for Gigabit EthernetEthernet over copper wire over copper wire

(IEEE Std. 802.3ab). The standard defines 1 Gb/s (IEEE Std. 802.3ab). The standard defines 1 Gb/s

data transfer over distances of up to 100 meters data transfer over distances of up to 100 meters

using four pairs of CAT-5 balanced copper cabling using four pairs of CAT-5 balanced copper cabling

and a 5-level coding scheme. and a 5-level coding scheme.

Other 1000Base-T benefits include compatibility Other 1000Base-T benefits include compatibility

with existing network with existing network protocolsprotocols (i.e. IP, IPX, (i.e. IP, IPX,

AppleTalk), existing applications, Network Operating AppleTalk), existing applications, Network Operating

Systems, Systems, network managementnetwork management platforms and platforms and

applications.applications.

Switched EthernetSwitched Ethernet

An An EthernetEthernet LANLAN that uses that uses switchesswitches to connect to connect individual individual hostshosts or or segmentssegments. In the case of . In the case of individual hosts, the switch replaces the individual hosts, the switch replaces the repeaterrepeater and effectively gives the device full 10 and effectively gives the device full 10 MbpsMbps bandwidth (or 100 Mbps for bandwidth (or 100 Mbps for Fast EthernetFast Ethernet) to the ) to the rest of the network. rest of the network.

Ethernet Frame TypesEthernet Frame Types

802.2802.2

802.3802.3

Ethernet IIEthernet II

Ethernet SNAPEthernet SNAP

802.2802.2

General standard for the data link layer in the General standard for the data link layer in the OSI Reference ModelOSI Reference Model. The IEEE divides this . The IEEE divides this layer into two sub layers -- the layer into two sub layers -- the logical link control logical link control (LLC) layer (LLC) layer and the and the media access control (MAC) layermedia access control (MAC) layer. .

Preamble8 bytes

Destinationaddress

Sourceaddress

Length2

bytesLLC

46 – 1500bytes

FCS4 bytes

DSAP1 byte

SSAP1 byte

ControlField

1 byte

802.3802.3

Defines the MAC layer for Defines the MAC layer for bus networksbus networks that use that use CSMA/CDCSMA/CD. This is the basis of the . This is the basis of the EthernetEthernet standard standard

Preamble7 bytes

Destinationaddress

Sourceaddress

46 – 1500bytes

LLCFCS

4 bytes

Length2

bytesSFC

1 byte

MauMau

Multistation Access UnitMultistation Access Unit a a token-ring networktoken-ring network device that physically device that physically

connects network computers in a connects network computers in a star topologystar topology while retaining the logical ring structure while retaining the logical ring structure

MAU is a special type of MAU is a special type of hubhub One of the problems with the token-ring topology One of the problems with the token-ring topology

is that a single non-operating is that a single non-operating nodenode can break can break the ring. The MAU solves this problem because the ring. The MAU solves this problem because it has the ability to short out non-operating it has the ability to short out non-operating nodes and maintain the ring structure nodes and maintain the ring structure

Design Considerations for Design Considerations for Token Ring NetworksToken Ring Networks

CablingCabling

Connectivity devicesConnectivity devices

# of stations# of stations

SpeedSpeed

ScalabilityScalability

TopologyTopology

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