11 Internetworking Concepts

7/28/2019 11 Internetworking Concepts

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InternetworkingConceptsOverview


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Components of the Network

Main OfficeBranch Office

Home

Office

Mobile

Users

Internet


3/24

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

Date post:	03-Apr-2018
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11 Internetworking Concepts

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