A Arokiaraj Jovith

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29 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

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A Arokiaraj Jovith

D. Hemavathi

Assistant Professor

SRM University, Kattankulathur

8/22/2011

School of Computing, Department of IT

1

8/22/2011

School of Computing, Department of IT

2



Distinguish between intra and
interdomain

routing



Understand distance vector routing and RIP



Understand link state routing and OSPF



Understand path vector routing and BGP



Routing

is

the

process

of

selecting

paths

in

a

network

along

which

to

send

network

traffic
.

Routing

is

performed

for

many

kinds

of

networks,

including

the

telephone

network,

electronic

data

networks

and

transportation

networks
.



Routing

inside

an

autonomous

system

is

referred

to

as

intra

domain

routing
.

Routing

between

autonomous

systems

is

referred

to

as

inter

domain

routing
.



8/22/2011

School of Computing, Department of IT

3

Popular routing protocols

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School of Computing, Department of IT

4

Initialization

Sharing

Updating

When to Share

Two
-
Node Loop Instability

Three
-
Node Instability

Distance vector routing tables

In

distance

vector

routing,

the

least

cost

route

between

any

two

nodes

is

the

route

with

minimum

distance
.

In

this

protocol

each

node

maintains

a

vector

(table)

of

minimum

distances

to

every

node

Distance Vector Routing

8/22/2011

School of Computing, Department of IT

5

Initialization of tables in distance vector routing

In distance vector routing, each node shares its routing table with its
immediate neighbors periodically and when there is a change.

8/22/2011

School of Computing, Department of IT

6

Updating in distance vector routing

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School of Computing, Department of IT

7

Two
-
node instability

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School of Computing, Department of IT

8

Three
-
node instability

8/22/2011`

School of Computing, Department of IT

9

The

Routing

Information

Protocol

(RIP)

is

an

intradomain

routing

protocol

used

inside

an

autonomous

system
.

It

is

a

very

simple

protocol

based

on

distance

vector

routing
.


Routing Information Protocol

RIP Message Format

Requests and Responses

Timers in RIP

RIP Version 2

Encapsulation

RIP message format

8/22/2011

School of Computing, Department of IT

10

Request messages

RIP timers

RIP uses the services of UDP on well
-
known port 520.

8/22/2011

School of Computing, Department of IT

11

RIP version 2 format

Authentication

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School of Computing, Department of IT

12

Link Sate Routing

In

link

state

routing,

if

each

node

in

the

domain

has

the

entire

topology

of

the

domain,

the

node

can

use

Dijkstra’s

algorithm

to

build

a

routing

table
.

Concept of link state routing

8/22/2011

School of Computing, Department of IT

13

Link state knowledge

Dijkstra algorithm

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School of Computing, Department of IT

14

Formation of shortest path tree

8/22/2011

School of Computing, Department of IT

15

Routing table for node A

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School of Computing, Department of IT

16

Open Shortest Path First (OSPF) protocol

The

Open

Shortest

Path

First

(OSPF)

protocol

is

an

intradomain

routing

protocol

based

on

link

state

routing
.

Its

domain

is

also

an

autonomous

system
.


Areas

Metric

Types of Links

Graphical Representation

OSPF Packets

Link State Update Packet

Other Packets

Encapsulation

8/22/2011

School of Computing, Department of IT

17

Areas in an autonomous system

Types of links

8/22/2011

School of Computing, Department of IT

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Example of an AS and its graphical representation in OSPF

8/22/2011

School of Computing, Department of IT

19

OSPF common header

8/22/2011

School of Computing, Department of IT

20

Gateway
:



A

gateway

is

a

network

point

that

acts

as

an

entrance

to

another

network
.

On

the

Internet,

a

node

or

stopping

point

can

be

either

a

gateway

node

or

a

host

(end
-
point)

node
.

Both

the

computers

of

Internet

users

and

the

computers

that

serve

pages

to

users

are

host

nodes
.



In

the

network

for

an

enterprise,

a

computer

server

acting

as

a

gateway

node

is

often

also

acting

as

a

proxy

server

and

a

firewall

server
.

A

gateway

is

often

associated

with

both

a

router,

which

knows

where

to

direct

a

given

packet

of

data

that

arrives

at

the

gateway,

and

a

switch,

which

furnishes

the

actual

path

in

and

out

of

the

gateway

for

a

given

packet
.



8/22/2011

School of Computing, Department of IT

21

ifconfig


Purpose

Configures

or

displays

network

interface

parameters

for

a

network

using

TCP/IP
.


Syntax

ifconfig

[
-
a]

[
-
s]

[
--
help]

[
--
version]

{
interface
}

[
address
]

[netmask{
address
}]

[gateway{
address
}]

[tftpserver{
address
}

]

[[up]

|

[down]]


Description

the

ifconfig

command

to

assign

an

address

to

a

network

interface

and

to

configure

or

display

the

current

network

interface

configuration

information
.

The

ifconfig

command

must

be

used

at

system

startup

to

define

the

network

address

of

each

interface

present

on

a

machine
.

After

system

startup,

it

can

also

be

used

to

redefine

an

interfaces

address

and

its

other

operating

parameters
.

The

network

interface

configuration

is

held

on

the

running

system

and

must

be

reset

at

each

system

restart
.

The

ifconfig

command

interprets

the

IFF_MULTICAST

flag

and

prints

its

value

if

it

is

set
.


8/22/2011

School of Computing, Department of IT

22

The netstat Command


netstat

is a useful tool for checking your network configuration and
activity. It is in fact a collection of several tools lumped together



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School of Computing, Department of IT

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REVIEW QUESTIONS:


1. State the function of netstat utility.

2.State the application of ifconfig command.

3. What are the different flags available in routing table? Explain it.

4. What is split horizon strategy?

5. What is the difference between inter domain routing and intra domain


routing?

6. Explain the operation of traceout program.

7. Draw the format of RIP message and explain about RIP request and


response messages.

8. Explain the operation of OSPF protocol.

9. State the difference between distance vector routing and link state
routing.

10. Explain anyone link state routing protocol.

11. Describe the formation of shortest path tree using Dijistras’s Algorithm