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Re: Route table growth and hardware limits...talk to the filter
IIRC, this has come up on cisco-nsp before, and the response has been that
The problem with this is that if you reject the routes initially and then later need them, then they're not in your incoming BRIB to reconsider. BGP is an incremental protocol. You can either save an update or you can ignore it, but if you ignore it, it's just plain gone.
If you do save it in your BRIB, then you can do this filtering between RIB and FIB. That turns out to be a completely local feature, requiring no protocol changes or additions whatsoever, and thus does not even require an RFC or Internet draft. This feature has been seen in some circles under the name "ORIB". Ask YFRV's PM for it. ;-)
Note that this feature *is* CPU intensive. This also does not decrease the RP RAM usage the way that update filtering would. In fact, due to the overhead of tracking filtered and non-filtered prefixes, there is additional RP RAM usage. YMMV.