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ben
New Member

BGP - route-map as-path VS prefix-list

Hello all,

I am configuring a 2600 series router to multi-home between two ISPs, and have a query about route filtering. In configuring the route advertisement & acceptance there seem to be two main ways to do it:

1. setup prefix-lists to filter routes by ip

or

2. setup as-path access-lists to filter with route-map

What are the current schools of thought on the relative benefits/disadvantges of these methods?

Cheers,

Ben Trigger

1 REPLY
Silver

Re: BGP - route-map as-path VS prefix-list

Typically you use both, you use the prefix list filters to deny inbound Matian addresses (as per draft-manning-dsua-08.txt) and to permit your outbound prefix and AS path filters for applying inbound policy (it is a lot simpler to apply policy via an AS path filter than a prefix list filter) and to prevent your AS becoming a transit AS via an outbound AS path filter (permit ^$ = Null AS Path).

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