RE: [nsp] Injecting Customer Statcis into BGP - Methods

From: Martin, Christian (cmartin@gnilink.net)
Date: Tue Sep 12 2000 - 18:18:38 EDT


This is good stuff. Most of these solutions have ben employed up to this
point. It is good to see that most are using BGP for this. I have some
tricky requirements to get around, but wanted to see what everyone else is
doing before I went ahead down a path that may lead to a re-design.

Thanks for the input.

chris

On Tue, 12 Sep 2000, Martin, Christian wrote:

> Folks,
>
> I'm interested in comparing methods to inject customer statics into BGP
(or
> an IGP if the method is slick). I'd like to hear some input as to the
> preferred methods of getting static entries into the routing table of
other
> routers, so that external announcements can be properly aggregated. In
> particular, I am looking for an elegant route-map type solution that
allows
> us to easily get statics into BGP, without leaking them outside the AS. I
> am thinking of using tags for customer statics, and then matching the tags
> before injection. The problem is, I'd have to go through and re-tag
> everything. I am also thinking of matching the next-hop, denying the
> private, non routable space, and so on. Any help would be appreciated.

Make up a set of communities (avoid using the "well known" ones
for anything but what they literally mean).
One value might be customer more-specifics you want to float internally
but supress in (most?) external announcements and another value for
exportable customer routes and another value for your CIDR blocks.

Tag the static routes in some mnemonically clear way.

Use a route-map to convert the "tag"-ed routes to BGP communities.

Set outbound route-maps on your external sessions which only match
the communities you know you want to pass. (Fails "safe" so that
inadvertently untagged routes don't leak.)

Tony



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