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InternetworkingConceptsOverview
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Components of the Network
Main OfficeBranch Office
Home
Office
Mobile
Users
Internet
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OSI Model Overview
Data FlowLayers
Transport Layer
Data Link
NetworkLayer
Physical
Application
(Upper)
Layers
Session
Presentation
Application
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Encapsulating Data
Transport
Data Link
Physical
Network
Upper Layer Data
Upper Layer DataTCP Header
DataIP Header
DataLLC Header
0101110101001000010
DataMAC Header
Presentation
Application
Session
Segment
Packet
Bits
Frame
PDU
FCS
FCS
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Upper Layer Data
De-encapsulating Data
LLC Hdr + IP + TCP + Upper Layer Data
IP + TCP + Upper Layer Data
TCP+ Upper Layer Data
Upper Layer Data
0101110101001000010
Transport
Data Link
Physical
Network
Presentation
Application
Session
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Physical Layer Functions
Defines
Media type
Connector type
Signaling type802.3
P
hysical
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Physical Layer: Ethernet / 802.3
Hub
Hosts
Host
10Base2
Thin Ethernet10Base5Thick Ethernet
10BaseT
Twisted Pair
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Hubs Operate at Physical layer
A B C D
Physical
All devices in the same collision domain
All devices in the same broadcast domain
Devices share the same bandwidth
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Hubs: One Collision Domain
More end stations means more
collisions CSMA/CD is used
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Data Link layer Functions
Defines
Physical source and
destination addresses
Higher layer protocol(Service Access Point)associated with frame
Network topology
Frame sequencing Flow control
Connection-oriented
or connectionless
DataL
ink
Phys
ical
EIA/TIA-232
v.35
802.2
802.3
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DataSource add FCSLengthDest add
Variable266 4
0000.0C xx.xxxx
Vendorassigned
IEEE assigned
MAC Layer - 802.3Data Link Layer Functions (cont.)
Ethernet II uses
Type here and
does not use
802.2.
# Bytes
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DataDSAP SSAP
DataSource add FCSLengthDest add
Variable11
802.2 (SAP)
MAC Layer - 802.3
Data Link Layer Functions (cont.)
Ctrl
1 or 2
3 2
DataDSAPAA
SSAP
AA
Variable11
802.2 (SNAP)
Ctrl
03
1 or 2
OR
OUI Type
# Bytes
# Bytes
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Each segment has its own collision domain
All segments are in the same broadcast domain
Data Link
Switches / Bridges Operate at Layer 2
OR1 2 3 1 24
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Switches
Each segment has its
own collision domain
Broadcasts are
forwarded to allsegments
Memory
Switch
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Network Layer Functions
Defines logical
source and
destination
addressesassociated with a
specific protocol
Defines paths
through network
Interconnects
multiple data links
Network
IP, IPX
DataLink
Physical
EIA/TIA-232
v.35
802.2
802.3
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Network Layer Functions (cont.)
11111111 11111111 00000000 00000000
10101100 00010000 01111010 11001100
BinaryMask
BinaryAddress
172.16.122.204
255.255.0.0
172 16 122 204
255
Address
Mask
255 0 0
Network Host
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Routing Table
NET INT Metric
124
S0S0E0
100
1.0 4.0
1.3
E0
4.3
S0
2.2
E0
2.1
S0
4.1
4.2
1.1
1.2
Routing Table
NET INT Metric
124
E0S0S0
001
Logical addressing allows for hierarchical network
Configuration required
Uses configured information to identify paths to networks
Network Layer Functions (cont.)
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Routers: Operate at the Network Layer
Broadcast control
Multicast control
Optimal pathdetermination
Traffic management
Logical addressing
Connects to WANservices
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Transport Layer Functions Distinguishes between
upper layer applications
Establishes end-to-end
connectivity betweenapplications
Defines flow control
Provides reliable orunreliable services for
data transfer
Network
IPXIP
Transport
SPXTCP UDP
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Reliable Transport Layer Functions
Synchronize
Acknowledge, Synchronize
Acknowledge
Data Transfer
(Send Segments)
Sender Receiver
Connection Established
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Network Device Domains
Hub Bridge Switch Router
Collision Domains:1 4 4 4
Broadcast Domains:
1 1 1 4
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Selection Issues:
Need for 10 Mbps or 100 Mbps on media
Port density
Need for management console
Easy Operations
Cisco 1500Micro Hub
Cisco
FastHub300
Cisco 1528
Micro Hub 10/100
Cisco
FastHub400
CiscoFastHub200
Cisco
FastHub100
Cisco Hub Products
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Selection Issues:
Need for 10 Mbps, 100 Mbps, or 1000 Mbps onmedia
Need for trunking and inter-switch links
Workgroup segmentation (VLANs)
Port density needs
Different user interfaces
Desktop/Workgroup
Solutions
Wiring
Closet/Backbone
Solutions
Cisco 1548 Micro
Switch 10/100
Catalyst
3000 series
Catalyst 2900
series XL
Catalyst
1900/2820 series
Catalyst
2900 series
Catalyst5000 series
Catalyst
8500 series
Catalyst Switch Products
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Selection Issues:
Scale of the routing features needed
Port density/variety requirements
Capacity and performance
Common user interface
Cisco
700/800
Series
Cisco1600/1700
Series
Cisco
2500
Series
Cisco3600
Series
Small Office Solutions
Branch Office Solutions
Central Site Solutions
Cisco12000 GSR
Series
Cisco
4000
Series
Cisco
7000
Series
Home Office Solutions
Cisco
2600
Series
Cisco Router Products