BGP aggregate address with the attributes inherited from the more specific routes ?

[ranga2002]

Hi guys,

This is one of the question I had on a paper. Can anyone explain the answer to this question briefly?

Question: When configuring an aggregate address with BGP, What addition to the aggregate-address configuration is needed to only advertise the aggregate-address with the attributes inherited from the more specific routes?

[Giuseppe Larosa]

Hello @ranga2002 ,

the question is not totally clear

the attributes are inherited by the all the component routes by default. There are rules for example for the origin attribute and so on.

However, it is possible to specify a sub set of component routes to be used to derive the aggregate route attributes using a route-map and invoking the route-map with an attribute-map.

see

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/command/irg-cr-book/bgp-a1.html#wp2343576123

Hope to help

Giuseppe

[paul driver · Accepted solution]

Hello

Sounds possibly like the AS-SET command, which is used to attach the AS-sequences that are specific all bgp routes for loop prevention, As in an aggregate route by default this as-path information is hidden.

[ranga2002]

Thank you, Giuseppe and Paul!