20402 routing entries

[Tony Li <]

   Expect more nets to fall off, perhaps to the point that we reach
   parity with the adds.  I'll be real pleased (and a bit surprised)
   if we actually reduce the total size of the tables.

Actually, I've been watching route-server.cerf.net.  We hit 20k the
week of IETF and have broken 21k.  We have seen some fluctuation in
size, but it's not clear if this is due to CIDR or normal weekly
bouncing.

Tony