Re: IGP Comparison (Summary of Responses)

From: Henk Smit <hsmit@cisco.com>

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.