Withdrawls and announcements attempt 2

Marten Terpstra marten at BayNetworks.com
Fri Jun 21 15:24:25 UTC 1996

"Justin W. Newton" <justin at erols.com> writes

 * Its /a little/ more complex than that.  The RFC does /not/ call for closing
 * down a BGP session when you change your route filters.  Cisco's have to do
 * this, but its not part of the RFC.  So, if I, for the sake of argument,
 * added a new filter /after/ I made an announcement to someone I would have to
 * somewhere keep track of the fact that I made the announcement.  It seems to
 * me that this could get to be a bit memory intensive (keeping track of the
 * state of every announcement made to every peer).
 * This leads me to wonder whether if we had infinite memory (just for the sake
 * of argument), if it would be more processor intensive to keep track of all
 * of your announcements or if the overhead invloved in dealing with withdrawls
 * that don't affect me is less.

There are however vendors out there that do exactly what you described
above and can therefore change policies and have them take effect
without having to take down a BGP session. And they only withdraw a
prefix if they sent an update for it in the first place.


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