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.

On Tue, 5 Jan 1999, Scott Brim wrote:
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. ------------------------------------------------------------------------------- Here we are. Born to be kings. We're the princes of the universe. Here we belong, fighting to survive in a war with the darkest power. Network Manager's Theme Song (QUEEN)

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.
There could be many reasons for not changing protocols running on a large scale network. One of them (an important one) is the cost of training supporting engineers and operational personnels. So it has to be a significant improvement of the protocol to-be or really broken of existing protocol to warrant such a change, IMO. --Jessica
participants (3)
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Bradley J. Passwaters
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Jessica Yu
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Scott Brim