Also sprach Iljitsch van Beijnum
It would be an interesting project to make an algorithm that takes a BGP table, and creates the shortest possible FIB that has traffic being forwarded in accordance with this BGP table. For dual homed networks, you should always be able to drop more than half the routes and install a default instead.
This isn't exactly true. Keep in mind that with a full BGP table and default-less, if you send traffic to a bogus IP address you would get a Host Unreachable from your router, drop half the routes and put a default in, and that traffic follows the default and at least makes it to the next hop before getting a host unreachable. This probably isn't a major deal, about the only real operational impact is that your link that the default points to gets a bit more traffic on it...whether it would be measurable is doubtful even...but this doesn't exactly fit the constraints of the project you described as the forwarding wouldn't be in accordance with the original BGP table. </nit> -- Jeff McAdams Email: jeffm@iglou.com Head Network Administrator Voice: (502) 966-3848 IgLou Internet Services (800) 436-4456