ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Policy-based Routing for BGP
– 1909 –
COMMAND USAGE
Aggregate routes advertised to a neighbor contain an aggregator attribute.
This attribute contains an AS number and IP address. The AS number is
the creator's AS number (or confed ID in a confederation) and an IP
address which is the creator’s router-id. The set aggregator as command
can be used to overwrite the aggregator attribute in routes created locally
with the aggregate-address command, or in routes learned from a
neighbor which already carry an aggregator attribute, or to add a new
aggregator attribute to a route which has no aggregator attribute.
EXAMPLE
Console(config)#route-map RD permit 8
Console(config-route-map)#match pathlimit as 5
Console(config-route-map)#set aggregator 1 192.168.0.0
Console(config-route-map)#
set as-path This command modifies the AS path by prepending or excluding an AS
number. Use the no form to remove this entry from a route map.
SYNTAX
set as-path {exclude | prepend} as-number...
no set as-path {exclude | prepend}
exclude – Removes one or more autonomous system numbers
from the AS path of the route that is matched.
prepend – Appends one or more autonomous system numbers to
the AS path of the route that is matched.
as-number – Autonomous system number. (Range: 1-4294967295)
COMMAND MODE
Route Map
COMMAND USAGE
Note that best path selection may be influenced with this command by
varying the length of the autonomous system path.
EXAMPLE
Console(config)#route-map RD permit 8
Console(config-route-map)#match peer 192.168.0.99
Console(config-route-map)#set as-path prepend 2
Console(config-route-map)#