class 19 - dynamic routing and routing ion protocol (rip) friday 16[1].11.07

8/3/2019 Class 19 - Dynamic Routing and Routing ion Protocol (RIP) Friday 16[1].11.07

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Dynamic Routing and RIP


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Autonomous System 100(used in same ISP network)

Autonomous System 200(used b/w different ISP)

IGPs: RIP, IGRP EGPs: BGP (Border Gateway Protocol

Autonomous Systems: Interior or Exterior

Routing Protocols

An autonomous system is one network or sets of networks under a single administrativecontrol and with common routing policies.

An autonomous system might be the set of all computer networks owned by a company

IGPs operate within an autonomous system

EGPs connect different autonomous systems


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Autonomous Numbers

1239 Sprintlink U.S. Domestic

3356 Level 3

7018 AT&T WorldNet

209 Qwest

3561

Cable and Wireless (aq'd by

SAVVIS)

3549 Global Crossing

2914 Verio

6461 AboveNet

702 UUnet (International)

1299 TeliaNet

5511 OpenTransit

5459 LINX

16631 Cogent

6453 Teleglobe

you can use any of the ASnumbers 64512 through 65535.

However, these numbers shouldNOT be seen on the globalInternet


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Classes of Routing ProtocolsClasses of Routing Protocols

Distance Vector

Hybrid Routing

Link StateCC

BB

AA

DD

CC

DD

BB

AA


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Distance Vector Routing Protocol

Adistance-vector routing protocol is one of the two major

classes of routing protocols used in packet-switched

networks for computer communications.

A distance-vector routing protocol requires that a router

informs its neighbors of topology changes periodically and, in

some cases, when a change is detected in the topology of a

network.


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Distance Vector Protocol

Distance Distance is the cost of reaching a destination, usually

based on the number of hosts the path passes through.

Vector path selected by the routing protocol as the best pathto the destination network.

E.g. RIP Routing Internet Protocol

IGRP- Interior Gateway Routing Protocol


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Distance Vector Routing ProtocolsDistance Vector Routing Protocols

Pass periodic copies of routing table to neighborrouters and accumulate distance vectors

CC

DD

BB

AA

CC BB AADD

Routing

Table

Routing

Table

Routing

Table

Routing

Table

DistanceHow farVectorIn which direction


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Distance VectorMaintaining Routing

Information

Distance VectorMaintaining Routing

Information

Updates proceed step-by-stepfrom router to router

AABB

Process toupdate this

routingtable

Process toupdate this

routingtable

Topologychangecausesrouting

tableupdate

Router A sendsout this updated

routing tableafter the

next periodexpires


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Routers discover the best path todestinations from each neighbor

AA BB CC

10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0

E0 S0 S0 S1 S0 E0

Routing Table

10.2.0.0

10.3.0.0

0

0

S0

S1

Routing Table

10.3.0.0 S0 0

10.4.0.0 E0 0

Routing Table

10.1.0.0

10.2.0.0

E0

S0

0

0

Distance VectorSources of Information and

Discovering Routes


Discovering Routes


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Routers discover the best path todestinations from each neighbor

AA BB CC

10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0

E0 S0 S0 S1 S0 E0

Routing Table

10.1.0.0

10.2.0.0

10.3.0.0

Routing Table

10.2.0.0

10.3.0.0

10.4.0.0

10.1.0.0

0

0

1

1

S0

S1

S1

S0

Routing Table

10.3.0.0 S0 0

10.4.0.0 E0 0

10.2.0.0 S0 1

E0

S0

S0 1

0

0


Discovering Routes


Discovering Routes


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Link-State Routing Protocols

Link-state protocols are those which requires arouter to inform all the nodes in a network oftopology changes

It has lots of computational complexity and messageoverhead.

Link state protocols know whether a link is up ordown and how fast it is and calculates a cost to 'get

there. link state protocols require more processing power


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makes decisions based on metric information it receives fromneighbors, and it employs some of the mechanisms of link-stateprotocols.

It establishes contact with neighboring routers, sends only changes in

its updates. E.g. Enhanced IGRP

Hybrid RoutingHybrid RoutingChoose a

routing path based

on distance vectors

Converge rapidly usingchange-based

updates

Balanced Hybrid Routing


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ProtocolsTwo types of protocols

1. Routing protocols RIP, IGRP, EIGRP, OSPF

2. Routed Protocols TCP/IP, IPX/SPX, Apple Talk


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19.2 kbps

T1

T1 T1

Hop count metric selects the path

Maximum hops it support is 15

RIP v1 is a Class full routing &RIP v2 is Classless Routing

RIP OverviewRIP Overview


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Defines an IP routing protocol

Router(config)#router protocol [keyword]

Mandatory configuration command for eachIP routing process

Identifies the physically connected network thatrouting updates are forwarded to

Router(config-router)#network

Dynamic RoutingC

onfigurationDynamic RoutingC

onfiguration


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Starts the RIP routing process

Router(config)#router rip

Router(config-router)#network

Selects participating attached networks The network number must be a major classful

network number

RIPC

onfigurationRIPC

onfiguration


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RIPC

onfiguration Example

Router B (config)#router rip

Router B (config-router)#network 20.0.0.0Router B (config-router)#network 30.0.0.0

10.16.1.1

S2E0 S3

40.168.1.120.1.1.1 30.2.2.220.1.1.2

S2 S3

30.2.2.3

10.16.1.0 A B C40.168.1.0

E0

Router A (config)#router rip

Router A (config-router)#network 10.0.0.0Router A (config-router)#network 20.0.0.0

Router C (config)#router rip

Router C (config-router)#network 30.0.0.0Router C (config-router)#network 40.0.0.0


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RIP Timer Value

10.16.1.1

S2E0 S3

40.168.1.120.1.1.1 30.2.2.220.1.1.2

S2 S3

30.2.2.3

10.16.1.0 A B C40.168.1.0

E0

Router update Timer : 30 seconds

Router invalid timer : 180 seconds

Holddown timer : 180 seconds

Router flush timer : 240 seconds


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RIP Timer value

Update timer: Update interval for routing table Invalid timer: If a router does not receive an

advertisement for a route in 180 seconds, the route is

marked as unreachable. Hold down timer: interval for routing information to be

stored.

Flush timer: will force the route to be flushed (removed)from the routing table


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RIPC

onfiguration Example

10.16.1.1

S2E0 S3

40.168.1.120.1.1.1 30.2.2.220.1.1.2

S2 S3

30.2.2.3

10.16.1.0 A B C40.168.1.0

E0

Router (config)#router ripRouter (config-router)# timer basic Router (config-router)# timer basic 30 180 180 240


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Verifying the Routing ProtocolRIP

172.16.1.1

S2E0 S3

192.168.1.110.1.1.1 10.2.2.210.1.1.2

S2 S3

10.2.2.3172.16.1.0 A B C 192.168.1.0

E0


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Verifying the Routing ProtocolRIPRouterA#sh ip protocols

Routing Protocol is "rip"

Sending updates every 30 seconds, next due in 0 seconds

Invalid after 180 seconds, hold down 180, flushed after 240

Outgoing update filter list for all interfaces is

Incoming update filter list for all interfaces is

Redistributing: rip

Default version control: send version 1, receive any version

Interface Send Recv Key-chain

Ethernet0 1 1 2

Serial2 1 1 2

Routing for Networks:

10.0.0.0

172.16.0.0

Routing Information Sources:

Gateway Distance Last Update

10.1.1.2 120 00:00:10

Distance: (default is 120)


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Command to view the Routing Table

172.16.1.1

S2E0 S3

192.168.1.110.1.1.1 10.2.2.210.1.1.2

S2 S3

10.2.2.3

172.16.1.0A B C

192.168.1.0E0


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Command to view the Routing TableRouterA#sh ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default

U- per-user static route, o - O

DRT - traffic engineered route

Gateway of last resort is not set

172.16.0.0/24 is subnetted, 1 subnetsC 172.16.1.0 is directly connected, Ethernet0

10.0.0.0/24 is subnetted, 2 subnets

R 10.2.2.0 [120/1] via 10.1.1.2, 00:00:07, Serial2

C 10.1.1.0 is directly connected, Serial2

R 192.168.1.0/24 [120/2] via 10.1.1.2, 00:00:07, Serial2

class 19 - dynamic routing and routing ion protocol (rip) friday 16[1].11.07

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