Chapter 12: Routing Protocols

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Oct 28, 2013 (3 years and 11 months ago)

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Chapter 12: Routing Protocols

Interior and Exterior

Routing Protocols

Aleksandar Radovanovic

University of the Western Cape

How a router learns about destinations

Static routes

--

manually defined by the system administrator as the
next hop to a destination and are useful for security and traffic
reduction

Default routes

--

manually defined by the system administrator as the path
to take when there is no known route to the destination

Dynamic routing

--

the router learns of paths to destinations by receiving
periodic updates from other routers

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Static route configuration

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Default route configuration

ip default
-
network 192.168.17

When an entry for a destination network does not exist in a routing
table, the packet is sent to the
default

network.

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Autonomous system


An autonomous system consists of routers, run by one or more operators.


The Network Information Center (NIC) assigns a unique autonomous
system to enterprises. This autonomous system is a 16 bit number.


A routing protocol such as Cisco's IGRP requires that you specify this
unique, assigned autonomous system number in your configuration.


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Interior versus exterior routing protocols

Exterior routing protocols
are used for
communications between
autonomous systems.


Interior routing
protocols are used
within a single
autonomous system
(RIP, IGRP)

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Interior IP routing protocols


Examples of IP routing protocols include:



RIP
--

a distance
-
vector routing protocol


IGRP
--

Cisco's distance
-
vector routing protocol


OSPF
--

a link
-
state routing protocol


EIGRP
--

a balanced hybrid routing protocol

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IP routing configuration tasks

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Using the router and network commands


The router command starts a routing process.


The network command enables the routing process to determine
which interfaces will participate in the sending and receiving of
routing updates