Switch User Manual

IP routing 25

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subnet mask (RIP version 2)

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routing table update based on the received RIP message

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global update timer

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holddown timer and timeout timer per device and per interface

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cost per device and per interface

The Nortel Ethernet Routing Switch 5500 Series implementation of RIP

also supports the following features:

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in and out routing policies

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auto-aggregation (also known as auto-summarization) of groups of

adjacent routes into single entries

Many RIP features are conﬁgurable. The actual behavior of the protocol

depends on the feature conﬁgurations.

RIP metrics

RIP is known as a distance vector protocol. The vector is the network

number and next hop, and the distance is the cost associated with the

network number. RIP identiﬁes network reachability based on cost, and

cost is deﬁned as hop count. The distance from one router to the next is

considered to be one hop. This cost or hop count is known as the metric The

illustration below depicts the hop counts between various units in a network.

RIP hop counts

A directly connected network has a metric of zero. An unreachable network

has a metric of 16. Therefore, 15 hops or 15 routers is the highest possible

metric between any two networks.

Nortel Ethernet Routing Switch 5500 Series

Conﬁguration-IP Routing Protocols

NN47200-503 03.01 Standard

5.1 27 August 2007