Do not carry a full routing table on your exchange point router. Only carry
routes to your customers and to networks with which you peer at that
particular exchange point.
If you are someone who is not going to be easilly able to detect this
through traffic stats, the likelihood is you are near enough tier one
that your routes + all your peer routes is very near a full routing table
I prefer Avi F's (?) idea pinging thru ach router on the fabric occasionally
using a dest address which is not in the routing table. If you see the
packets coming back at you rather than !H you know someone is defaulting.