Re: IGPs in use

[Tony Li <tli () juniper net>]

scharf () vix com (Jerry Scharf) writes:

> One thing about IS-IS that is quite different from OSPF and all the other
> IGPs is that the neighbor traffic is not in IP but instead is done at
> layer 2. Some say this is a good thing. I have never run into a case
> where I couldn't get it to do what I wanted, but always suspected there
> would be. Would this force ATM links to move to the less efficient SNAP
> based encoding (if so, there's 4% of your bandwidth)?


Yes, however, let's be accurate here: the problem is NOT that IS-IS runs
over the link layer.  The problem is that it doesn't run over IP.  Even if
it ran over another network layer protocol, you'd still require an
additional demux layer.  

One might point out that SNAP is perhaps not the most efficient of all
encapsulations anyhow.  Nor is ATM.

Tony