On 9/24/19 1:21 PM, Cassidy B. Larson wrote:
Dont bother importing all the 760k routes learned from your upstream providers into your core. Having that many routes is only going to impact your egress traffic to the Internet, which is probably a drop in the bucket compared to your ingress traffic loads (Netflix, CDNs, etc). Just advertise a default route into the core from both providers and your core can figure out which way to go to get to the Internets.
If you're multihoming you really should consider a full feed, depending on how much you like to sleep.
A couple weeks ago, a carrier POP that I and some of my customer use had an issue where their transport carrier died in a way that took down all transports. The carrier's POP router was still up, as was BGP and interfaces, but if you looked at the BGP neighbors there were only a handful of routes coming from them. Relying on a default route effectively sending your traffic into a black hole, whereas if you'd been routing based on prefixes you'd stop sending traffic as the prefixes withdrew when it became islanded. I didn't even notice until the carrier called me on the emergency number and said hey we can't reach our equipment, and I was like that's odd because your interface+BGP is still up but I'm only seeing a few prefixes from you, at which point the larger transport issue was discovered.
~Seth -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com
