[ns] Adding IS-IS as a routing protocol

[Rob Ballantyne <ballanty@sfu.ca>]

  Hi All,

  I've taken on a class project to simulate to a high-fidelity the IS-IS
routing protocol and further to adjust parameters and algorithms that it
might use to attempt to speed convergence after a topology change.

  I'm having troubles though.  I don't quite see where to disable the
default
routing and where to hook in my own IS-IS routing entitity at each node.
It's also not obvious to me how to simulate IPv4 packet addresses (with
various length prefix matches at each node) with the heirarchical
addressing
scheme.

  I'm hoping that someone has an example that I can look at or is
willing
to pass on other advice.

  Many Thanks,

Rob