Juniper JUNOSE 11.2.X BGP AND MPLS Configuration Manual page 96

JunosE 11.2.x BGP and MPLS Configuration Guide
aggregate-address
60
attribute is not set for the aggregated route. The following commands configure router
SanJose to aggregate the routes while preserving the path information:
host2(config)#router bgp 873
host2(config-router)#neighbor 10.2.2.3 remote-as 873
host2(config-router)#neighbor 10.5.5.1 remote-as 17
host2(config-router)#network 172.24.24.0 mask 255.255.248.0
host2(config-router)#aggregate-address 172.24.0.0 255.255.224.0 summary-only as-set
If you do not want to aggregate all more specific routes, you can use a route map to limit
aggregation. Consider Figure 17 on page 59 again. Suppose you do not want router SanJose
to aggregate prefix 172.24.48.0/20. The following commands show how you can configure
a route map on router SanJose to match this prefix, and how to invoke the route map
with the advertise-map option:
host2(config)#router bgp 873
host2(config-router)#neighbor 10.2.2.3 remote-as 873
host2(config-router)#neighbor 10.5.5.1 remote-as 17
host2(config-router)#neighbor 10.2.2.3 route-map lmt_agg in
host2(config-router)#network 172.24.24.0 mask 255.255.248.0
host2(config-router)#aggregate-address 172.24.0.0 255.255.224.0 advertise-map lmt_agg
host2(config-router)#exit
host2(config)#route-map lmt_agg permit 10
host2(config-route-map)#match ip address 1
host2(config-route-map)#exit
host2(config)#access-list 1 permit 172.24.48.0 0.240.255.255
You can use the attribute-map option to configure attributes for the aggregated route.
In Figure 17 on page 59, suppose that router LA has been configured to set the community
attribute for route 172.24.160.0/19 to no-export. This attribute is passed along to router
SanJose and preserved when the aggregate route is created. As a result, the aggregate
route is not advertised outside the AS. The following commands demonstrate how to
configure router SanJose to prevent the aggregate from not being advertised:
host2(config)#router bgp 873
host2(config-router)#neighbor 10.2.2.3 remote-as 873
host2(config-router)#neighbor 10.5.5.1 remote-as 17
host2(config-router)#network 172.24.24.0 mask 255.255.248.0
host2(config-router)#aggregate-address 172.24.0.0 255.255.224.0 attribute-map
conf_agg_att
host2(config-router)#exit
host2(config)#route-map conf_agg_att permit 10
host2(config-route-map)#set community no-export
Use to create an aggregate entry in a BGP routing table that summarizes more specific
routes.
For IPv4 routes, you must specify an aggregate IP address (address) and aggregate
IP mask (mask). For IPv6 routes, you must specify an aggregate IPv6 prefix (ipv6Prefix).
The optional as-set keyword preserves path information by creating an AS-Set that
contains all the AS numbers traversed by the aggregated routes.
Copyright © 2010, Juniper Networks, Inc.