AGIS upgraded its router at the Sprint NAP to an RSP (from SP/SSP), and at
the same time had to upgrade the FDDI interface. It hasn't really worked
right since. It turns out through experimentation, any return traffic
coming through Pennsauken dies on that router. So we've essentially taken
the Sprint NAP router off the net while we figure out what's wrong. [That,
by the way, is why it's so important to see as many networks in as many
places as possible.]

We've spent the time since try to determine if we have:

- a FDDI problem

When switching cards/upgrading things, you could try setting the old
mac address in software for the new fddi interface, if the fddi card
itself is new (has a different mac address). This is a common problem
with hot-swapping ethernets - switches and other routers sometimes don't
expire arp properly.

- an RSP problem
- an undesirable SMDS/IOS interaction (we use SMDS to get into Pennsauken
from our net)

11.0.9 works weel for us on 7505s.

- some other undesireable hardware/IOS interaction
- routing or other configuration on the Pennsauken router
- routing or other configuration on any other router

I'll let you know what we find out. We've pretty much eliminated routing
or FDDI, and are looking at SMDS/IOS or some other config issue.


These things are a bitch...
Good luck,