Transcript Chapter 12 - University of the Western Cape

Chapter 12: Routing Protocols
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Interior and Exterior
Routing Protocols
Aleksandar Radovanovic
How a router learns about destinations
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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
Default route configuration
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When an entry for a destination network does not exist in a routing
table, the packet is sent to the default network.
ip default-network 192.168.17
Autonomous system
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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.
Interior versus exterior routing protocols
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Exterior routing protocols
are used for
communications between
autonomous systems.
Interior routing
protocols are used
within a single
autonomous system
(RIP, IGRP)
Interior IP routing protocols
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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
Using the router and network commands
The router command starts a routing process.
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The network command enables the routing process to determine
which interfaces will participate in the sending and receiving of
routing updates