SMC Networks SMC6724L3 manual 208, Configuring Summary Addresses for External AS Routes

CONFIGURING THE SWITCH

CLI - This example configures the backbone area and one transit area.

Console(config-router)#network 10.0.0.0 255.0.0.0
area 0.0.0.0	4-255

Console(config-router)#network 10.1.1.0 255.255.255.0 area 0.0.0.1 Console(config-router)#end

Console#show ip ospf		4-271
Routing Process with ID 10.1.1.253
Supports	only single TOS(TOS0) route
Number of area in this router is 4
Area 0.0.0.0 (BACKBONE)
Number of interfaces in this area is 1
SPF	algorithm executed 8 times
Area 0.0.0.1
Number of interfaces in this area is 1
SPF	algorithm executed 5 times
Area 0.0.0.2 (STUB)
Number of interfaces in this area is 1
SPF	algorithm executed 13 times
Area 0.0.0.3 (NSSA)
Number of interfaces in this area is 1
SPF	algorithm executed 12 times
Console#

Configuring Summary Addresses (for External AS Routes)

An Autonomous System Boundary Router (ASBR) can redistribute routes learned from other protocols into all attached autonomous systems. (See “Redistributing External Routes” on page 3-210)To reduce the amount of external LSAs imported into your local routing domain, you can configure the router to advertise an aggregate route that consolidates a broad range of external addresses.

Command Usage

•If you are not sure what address ranges to consolidate, first enable external route redistribution via the Redistribute Configuration screen, view the routes imported into the routing table, and then configure one or more summary addresses to reduce the size of the routing table and consolidate these external routes for advertising into the local domain.

•To summarize routes sent between OSPF areas, use the Area Range Configuration screen (page 3-196).

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