Example 3: Summarizing Routes; Figure 4-7 Summarizing Routes - Nortel Web OS Switch Software Application Manual

Web OS 10.0 Application Guide

Example 3: Summarizing Routes

By default, ABRs advertise all the network addresses from one area into another area. Route
summarization can be used for consolidating advertised addresses and reducing the perceived
complexity of the network.
If the network IP addresses in an area are assigned to a contiguous subnet range, you can con-
figure the ABR to advertise a single summary route that includes all the individual IP
addresses within the area.
The following example shows one summary route from area 1 (stub area) injected into area 0
(the backbone). The summary route consists of all IP addresses from 36.128.0.0 through
36.128.254.255 except for the routes in the range 36.128.200.0 through 36.128.200.255.

Figure 4-7 Summarizing Routes

N
OTE
In this example, routes in the range 36.128.200.0 through 36.128.200.255 are kept private.
Follow this procedure to configure OSPF support as shown in
1. Configure IP interfaces for each network which will be attached to OSPF areas.
>> # /cfg/ip/if 1
>> IP Interface 1 # addr 10.10.7.1
>> IP Interface 1 # ena
>>
IP Interface 1 # ../if 2
>> IP Interface 2 # addr 36.128.192.1
>> IP Interface 2 # ena
2. Enable OSPF.
>> IP Interface 2 # /cfg/ip/ospf/on
n
90 Chapter 4: OSPF
Backbone
Area 0
(0.0.0.0)
IF 1
10.10.7.1
Summary
Route
10.10.7.0/24
Network
–
You can specify a range of addresses to prevent advertising by using the hide option.
Stub Area
Area 1
(0.0.0.1)
IF 2
36.128.192.1
36.128.192.x to
36.128.254.x
ABR
36.128.192.0/18
Network
(Select menu for IP interface 1)
(Set IP address on backbone network)
(Enable IP interface 1)
(Select menu for IP interface 2)
(Set IP address on stub area network)
(Enable IP interface 2)
(Enable OSPF on the Web switch)
Figure 4-7:
212777-A, February 2002