BGP routes from Internet

[lasheliabogan]

Is it possible for an ISP to recieve the full BGP routes from thier upstreams and only pass the default routes to several customers and the full routes to others?

[Richard Burts]

LaShelia

Yes it is possible, and quite commonly done, for an ISP to receive full BGP routes from its upstream and for that ISP to advertise just a default route to some customers, and to advertise full routes to other customers. The ISP (or anyone running BGP for that matter) can control what (and how many) routes are advertised to neighbors by using route maps, or distribute lists which are configured on a neighbor by neighbor basis.

HTH

Rick

[keeleym]

Hi There

Rick beat me to it.

I was going to say that according to my CCNP (BSCI) studies an ISP as the following options,

Send default routes only into the AS. (least amount of load on the router)

Send default routes and selected specific routes into the AS

Send all routes into the AS

Best Regards,

Michael

[lasheliabogan]

Thanks Rick for responding, I've been told that this couldn't be done. So it's great to know that I can do this. Thanks again!

[Richard Burts]

LaShelia

Perhaps the person that you were talking to was aware of some aspect of your requirements that was not reflected in the question that you asked. But for the question that you asked, the answer is very definitely yes an ISP can learn full routes from its upstream, and can advertise just the default route to some customers, and can advertise full routes to other customers. And as Michael very correctly noted the ISP can advertise default route and selected routes to other customers.

HTH

Rick