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CCNA Semester 2

Chapter 06Chap

ter 06

ROUTING ANDROUTING ANDROUTINGROUTING

PROTOCOLSPROTOCOLS

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ObjectivesObjectives

Explain the significance of static routing Configure static and default routes

Identify the classes of routing protocols

Identify distance vector routing protocols Identify link-state routing protocols

Describe the basic characteristics of commonrouting protocols

Identify interior gateway protocols

Identify exterior gateway protocols

Enable Routing Information Protocol (RIP) on

a router

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Table of ContentTable of Content

1 Introduction to static route

2 Dynamic routing overview

3 Routing protocols overview

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INTRODUCTION TO STATIC ROUTINGINTRODUCTION TO STATIC ROUTING

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Introducing RoutingIntroducing Routing

Routing is the process that a router uses to forwardpackets toward the destination network

Static routing & dynamic routing

Static routing

must be configured manually

Network topology changes require the networkadministrator to add and delete static routes to account forthe changes.

Static route requires a tremendous amount of adm. time. Static routing does not have the scalability of dynamic

routing.

Dynamic routing

The direction to remote networks is learned from otherrouters

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Introducing RoutingIntroducing Routing

Purpose of a static route Security

When a network is accessible by only one path(stub network), static route to the network can be

sufficient

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Static Route OperationStatic Route Operation

Static route operations can be divided intothese three parts:

Network administrator configures the route

Router installs the route in the routing table The static route is used to route packets.

Router(config) ip route des_net subnet_mask [next-hop-addresoutgoing interface]

Hobeken(config)# ip route 172.16.1.0 255.255.255.0 s1 Command des. Net subnetmask interface

Hobeken(config)#ip route 172.16.1.0 255.255.255.0 172.16.Command des. Net subnetmask nexthop ad

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Static Route ExampleStatic Route Example

This is a unidirectional route. You must have a route

configured in the opposite direction.

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Static Route OperationStatic Route Operation

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Static Route OperationStatic Route Operation

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Configuring Static RoutesConfiguring Static Routes

Step 1 Determine all desired prefixes,masks, and addresses. The address can beeither a local interface or a next hop addressthat leads to the desired destination.

Step 2 Enter global configuration mode. Step 3 Type the ip route command. The

administrative distance is optional.

Step 4 Repeat Step 3 for all the destinationnetworks that were defined in Step 1.

Step 5 Exit global configuration mode.

Step 6 Use the copy running-config

startup-config.

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Configuring Default Route ForwardingConfiguring Default Route Forwarding

Sterling Hoboken waycross

172.16.1.1/24 172.16.3.1/24 172.16.5.1/24

172.16.2

.1/24

172.1

6.2.2/24

172.1

6.4.1/24

172.16.4

.2/24

S0 S0S1 S1

obeken(config)# ip route 0.0.0.0 0.0.0.0 [next-hop-addre outgoing interface]

Default routes are used to route packets with destinationsthat do not match any of the other routes in the routing table

obeken(config)#ip route 0.0.0.0 0.0.0.0 s0

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Default Routes ExamplesDefault Routes Examples

This route allows the stub network to reach all known

networks beyond router A.

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Verifying & Troubleshoot Static Route ConfigurationVerifying & Troubleshoot Static Route Configuration

show running-config to view the active

configuration show ip route to verify that the route that

was configured is in the routing table.

Ping Traceroute

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Verifying & Troubleshoot Static Route ConfigurationVerifying & Troubleshoot Static Route Configuration

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DYNAMIC ROUTING OVERVIEW

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Introduction To Routing ProtocolsIntroduction To Routing Protocols

A routing protocol allows one router to shareinformation with other routers.

E.g: RIP, IGRP, EIGRP, OSPF

A routed protocol provides enoughinformation in its network layer address toallow a packet to be forwarded from one hostto another based on the addressing scheme.

E.g IP,IPX,

An autonomous system (AS) is a collection ofnetworks under a common administration

sharing a common routing strategy

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Purpose Of A Routing Protocol & Autonomous SystemsPurpose Of A Routing Protocol & Autonomous Systems

The goal of a routing protocol is to build andmaintain the routing table.

The routing protocol learns all available

routes, places the best routes into the routingtable

When all routers in an internetwork areoperating with the same knowledge, the

internetwork is said to have converged

Autonomous systems (AS) provide thedivision of the global internetwork into

smaller and more manageable networks.

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Identifying The Classes Of Routing ProtocolsIdentifying The Classes Of Routing Protocols

Most routing algorithms can be classified into

one of two categories: The distance vector routing approach determinesthe direction (vector) and distance to any link inthe internetwork.

The link-state approach, also called shortest pathfirst, recreates the exact topology of the entireinternetwork.

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Distance Vector Routing Protocol FeaturesDistance Vector Routing Protocol Features

10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0

10.1.0.0 0Routing Table

10.2.0.0 010.2.0.0 0Routing Table

10.3.0.0 010.3.0.0 0Routing Table

10.4.0.0 0

10.3.0.0 1 10.1.0.0 1 10.2.0.0 110.4.0.0 1

10.4.0.0 2 10.1.0.0 2

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Link-state Routing Protocol FeaturesLink-state Routing Protocol Features

10.3.0.0 10.4.0.0

B

10.2.0.0 10.3.0.0

CA

10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0

Hello Hello

10.1.0.0 10.2.0.0

B

10.2.0.0 10.3.0.0

CA

10.3.0.0 10.4.0.0

B

A B C

SPF

LSU

LSU

Routing Table

10.1.0.0 010.2.0.0 010.3.0.0 110.4.0.0 2

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ROUTING PROTOCOLS OVERVIEW

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Path DeterminationPath Determination

Path determination occurs at the networklayer.

The path determination function enables arouter to evaluate the paths to a destinationand to establish the preferred handling of apacket

The switching function is the internal processused by a router to accept a packet on oneinterface and forward it to a second interfaceon the same router.

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Routing ConfigurationRouting Configuration

Network 172.16.0.0

Network 172.30.0.0

RIP

RIP

RIP

IGRP

IGRP

Network 160.89.0.0

Global configuration

Select routing protocol(s)

Specify Network(s)

Interface configuration

Verify address/subnet mask

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Routing Configuration ( cont. )Routing Configuration ( cont. )

Router(config)# routerprotocol {options} Difines an ip routing protocol

Protocol: IGRP, OSPF,EIGRP,RIP

Option: autonomous system or process id ifrequired

Router(config-router)# networknetwork-number

The network subcommand is a mandatoryconfiguration command for each ip routing

process

Network-number: specifies a directly connected

network

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Routing ProtocolsRouting Protocols

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Interior/Exterior Routing ProtocolsInterior/Exterior Routing Protocols

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Routing Information Protocol (RIP)Routing Information Protocol (RIP)

It is a distance vector routing protocol.

Hop count is used as the metric for path

selection. If the hop count is greater than 15, the

packet is discarded.

Routing updates are broadcast every 30seconds, by default.

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Interior Gateway Routing Protocol (IGRP)Interior Gateway Routing Protocol (IGRP)

It is a distance vector routing protocol.

Bandwidth, load, delay and reliability areused to create a composite metric.

Routing updates are broadcast every 90

seconds, by default.

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Open Shortest Path First (OSPF)Open Shortest Path First (OSPF)

It is a link-state routing protocol.

Open standard routing protocol described inRFC 2328.

Uses the SPF algorithm to calculate thelowest cost to a destination.

Routing updates are flooded as topologychanges occur

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Enhanced Interior Gateway Routing Protocol (EIGRP)Enhanced Interior Gateway Routing Protocol (EIGRP)

It is an enhanced distance vector routingprotocol.

Uses load balancing.

Uses a combination of distance vector andlink-state features.

Uses Diffused Update Algorithm (DUAL) to

calculate the shortest path. Routing updates are multicast using

224.0.0.10 triggered by topology changes

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SummarySummary

Routing protocols

Autonomous systems

The classes of routing protocols Routing configuration

Routing protocols (RIP, IGRP, OSPF, EIGRP,BGP)

Autonomous systems and IGP versus EGP

Distance vector routing

Link-state routing

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Q&AQ&A