[c-nsp] BGP Filter - Best Practice

[Ahmed Hilmy]

Hello Nick,

Thanks for your reply, i am totally agree with you.

Regards,
Ahmed


On Tue, Apr 16, 2013 at 9:12 PM, Nick Hilliard <nick at foobar.org> wrote:

> On 15/04/2013 21:44, Ahmed Hilmy wrote:
> > I am using Prefix-list and as-path for BGP filter.
> > But if i  apply Prefix-list as inbound filter at PE, then from PE to RR (
> > Route Reflector ) i apply as-path filter, i think it is more scalable
> than
> > modify Prefix-list continuously ? or use community ?
> > If my question not clear please ask me.
>
> it depends.
>
> Prefix lists are very fast because they are implemented as a trie, and it
> is very fast to look up an entry in a trie.
>
> Community lists can be fast (standard, i.e. integer comparison) or slow
> (extended, i.e. regular expression).
>
> as-path lists are slow because they use regular expressions.
>
> If you need to filter BGP updates, it is usually fastest to use prefix
> lists or standard community lists.  It makes little difference whether you
> use extended communities or as-path lists - both are slow.
>
> Nick
>
>
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