Nortel Networks NN47200-503 manual Using RIP accept policies, End

130IP Routing Configuration and Management

5530-24TFD(config-if)# ip rip receive version rip2

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Using RIP accept policies

RIP accept policies are used on the Nortel Ethernet Routing Switch 5500 Series to selectively accept routes from RIP updates. If no policies are defined, the default behavior is applied. This default behavior is to add all learned routes to the route table. RIP accept policies are used to:

•Listen to RIP updates only from certain gateways.

•Listen only for specific networks.

•Assign a specific mask to be included with a network in the routing table (such as a network summary).

In the configuration illustrated below, the Nortel Ethernet Routing Switch 5500 Series (ERS1) is configured with a RIP accept policy. This creates a single route directed to ERS3 for all networks configured on it. The accept policy accepts any network from 10.1.240.0 to 10.1.255.0, and creates a single entry in the routing table on ERS1.

A summary route is calculated by comparing the common bits in the address range to derive the summary address. For example, if the range of IP addresses is from 10.1.240.0 to 10.1.255.0:

1.Determine the third octet of the first address: 10.1.240.0 = 1111 0000.

2.Determine the third octet of the ending address: 10.1.255.0 = 1111 1111.

3.Extract the common bits: 240 = 1111 0000 255 = 1111 1111 1111 = 20 bit mask.

Therefore, the network address to use for this example is 10.1.240.0/20

Nortel Ethernet Routing Switch 5500 Series

Configuration-IP Routing Protocols

NN47200-503 03.01 Standard

5.127 August 2007

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