Posted Jul 21, 2011 18:48 UTC (Thu) by hmh (subscriber, #3838)
In reply to: IPv6 NAT by raven667
Parent article: IPv6 NAT
BGP multihoming requires PI space, which does increase the routing table size _always_.
That's not the problem. The problem is that you pretty much have to de-aggregate your announcements to do traffic engineering, and that inflates the table a LOT more. And very large ISPs won't aggregate it back later: http://www.cidr-report.org/as2.0/#Gains
The number of updates per second is just a matter of not using wimpy router CPUs to deal with large BGP feeds in the first place, and not doing full table feeds where it is not needed so that wimpy routers just have to deal with less than 5k routes and a few updates per minute.
Route table size is different, supporting very large route tables on high-speed routers is not that easy. However, I am still waiting to see a hardware router which does for its distributed TCAMs what your typical high-end CPU does for its L1/L2 cache. If anyone knows of a vendor that does this, please share.