We are looking into using a full or partial mesh MPLS overlay for traffic
characterization on our network and need a tool to model utilization and
simulate failures. At first we won't be doing any real TE.
The MPLS network simulator perhaps? http://flower.ce.cnu.ac.kr/~fog1/mns/
There's something called Deriveit that you can get on a 30 day trial which
might be sufficient for some people.
--Michael Dillon