Re: Question about the use of NO_EXPORT in BGP route announcements

On Sep 20, 2024, at 8:59 AM, Elmar K. Bins <elmi@4ever.de> wrote:

We're deploying enough nodes to be able to run it that way, and we have - of course - a few nodes that advertise a supernet without NO_EXPORT to service whoever isn't peering with us.

The supernet piece of this is key. NO_EXPORT can be a useful traffic engineering tool if you want to give a nearby network more specific instructions about how to reach you than you want to give the Internet as a whole. But by its nature, it creates reachability issues — any network who uses your NO_EXPORT prefix won’t export ANY prefix to your address space. If there’s a supernet that covers the smaller NO_EXPORT prefix, that handles the routing issue. -Steve