CISCO IOS in a Nutshell

Name

aggregate-address — router, BGP

Synopsis

aggregate-address address mask [as-set] [summary-only] [suppress-map map] 
    [advertise-map map] [attribute-map map]
no aggregate-address address mask [as-set] [summary-only] [suppress-map map] 
    [advertise-map map] [attribute-map map]

Configures

BGP route aggregation

Default

Disabled

Description

This command configures route aggregation when using BGP. An aggregate route is generated by combining several different routes. The new route covers all the smaller routes with a single route, making the routing table smaller and easier to manage.

address

The IP address of the destination network for the aggregate route.

mask

The network mask for the aggregate route.

as-set

Optional. Generates AS-SET path information.

summary-only

Optional. This keyword causes routes that are more specific than the aggregate address to be suppressed.

suppress-map map

Optional. The map to use to select routes to be suppressed.

advertise-map map

Optional. The map to use to select routes to create AS-SET origin communities.

attribute-map map

Optional. The map to use to set the attributes of the aggregate route.

Example

Say that we’re configuring a router for the network 10.10.0.0. Instead of advertising all the routes within this network that we know about (10.10.1.0, 10.10.2.0, etc.), we want to advertise an aggregrate address for the whole 10.10.0.0 network:

! BGP configuration router bgp 100 neighbor 10.1.1.1 remote-as 100 neighbor 10.2.2.2 remote-as 200 network 10.10.0.0 ...