BGP aggregate

[sun816]

f I aggregate 192.168.0.0 255.255.0.0 as-set

(one specific route with community no-export another with no-advertise)

will the aggregated route with community no-export or no-advertise ?

[aretana]

rfc1997 reads:

If a range of routes is to be aggregated and the resultant aggregates attribute section does not carry the ATOMIC_AGGREGATE attribute, then the resulting aggregate should have a COMMUNITIES path attribute which contains all communities from all of the aggregated routes.

In your case, the use of 'as-set' should result in not carrying the ATOMIC_AGGREGATE attribute...so all the communities should be present.

In the specific example, no-advertise would take "priority" (because it includes the no-export semantics) in terms of operation.

[sun816]

Thanks a lot.

but can I consider that a bgp route with multiple well known communitis will prefer no-advertise than no-export than none ?

And another maybe infant question for consult: for example:An border router receive an ibgp learned route with local_pref is 100 and the same prefix learned from EBGP with none local_pref ,will the local_pref be exclude outside the processing decide for this prefix?

sun

[t.baranski]

I believe the IBGP route will be preferred in this case due to the higher local preference.