Nortel Networks WEB OS 212777 - Manual (Page 90)

Web OS 10.0 Application Guide
90 n Chapter 4: OSPF
212777-A, February 2002
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 – You can specify a range of addresses to prevent advertising by using the hide option.
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 Figure 4-7 :
1. Configure IP interfaces for each network which will be attached to OSPF areas.
2. Enable OSPF.
>> # /cfg/ip/if 1 (Select menu for IP interface 1)
>> IP Interface 1 # addr 10.10.7.1 (Set IP address on backbone network)
>> IP Interface 1 # ena (Enable IP interface 1)
>> IP Interface 1 # ../if 2 (Select menu for IP interface 2)
>> IP Interface 2 # addr 36.128.192.1 (Set IP address on stub area network)
>> IP Interface 2 # ena (Enable IP interface 2)
>> IP Interface 2 # /cfg/ip/ospf/on (Enable OSPF on the Web switch)
IF 1
10.10.7.1
IF 2
36.128.192.1
Area 1
(0.0.0.1)
36.128.192.x to
36.128.254.x
Area 0
(0.0.0.0)
Summary
Route
ABR
Stub Area Backbone
36.128.192.0/18
Network
10.10.7.0/24
Network