[c-nsp] Load-balancing T1s on a Cisco 7600

[Cory Ayers]

We recently upgraded multiple Cisco 7200s serving as aggregation routers
to Cisco 7606s.  We found that ip load-sharing per-packet with CEF was
not an option due to the distributed architecture of a 7600.  We
attempted to use MLPoFR and MLPoATM, but neither of these worked, so we
opened a TAC case.  We were told that multilink PPP isn't going to work
on the 7600 and were advised to have our telephone company bundle the
circuits for us and hand us a single PVC.  This is not a valid option as
it would affect 500 end-sites and mean dealing with nearly 30 different
telephone companies.  Our other option appears to be to remove the Cisco
7600s that we recently purchased in favor of a non-distributed
architecture.

Currently, we have both Frame-to-Frame and Frame-to-ATM terminating on
the 7600.  The Frame-to-Frame circuits terminate on a PA-T3+ housed in
an Enhanced FlexiWAN.  Multiple DS3 and OC-3 ATM circuits terminate on
an LS-1010 and are fed to the 7600 on an OSM-2OC12-ATM-MM+.

Has anyone successfully configured Multilink PPP over Frame or ATM in
this scenario?

Is there a work-around for CEF load-sharing per-packet that will allow a
single flow to utilize multiple T1 circuits?

Does the Cisco 10000 (ESR) boast similar issues with load-balancing
multiple T1 circuits?

The Cisco 7200 has been a work horse for us for many years, but lacks
the port density, processor, and Gigabit fabric.  We have upgraded to an
NPE-G1 in some scenarios, but this doesn't address high density circuit
aggregation.  What other routers are people using to fill this need?

Thanks!
~cayers