IGP Comparison (Summary of Responses)

Most of the large ISPs in the US run IS-IS as their IP IGP.
In europe a number of PTTs have chosen IS-IS as the IGP for their new
IP Internet backbones. That might be an indication if IS-IS is dead.

This points out the real issue. OSPF and IS-IS are close enough that other
factors usually outweigh their differences. The choice of IS-IS in this
case is really the result of the choice of an equipment vendor. These days
at least, vendors are not chosen because they implement IS-IS. IS-IS is
chosen because of some vendors' protocol implementations.

It may have been the result of vendor choice/issue in the past but I don't
see to many people running IS-IS planning to switch over any time soon.

For the record there a number of shops were the lack of IS-IS would
make your product a non-starter. (now if you don't want to sell
those billion dollar plus networks then no you don't need to
implement IS-IS)

bjp@eng.umd.edu | Disclaimer: Can you be sure I even
uunet!eng.umd.edu!istari | exist: Let alone represent anyone
Brad Passwaters (Network Ronin) | or anything.