Frame-Relay, ATM, IP, X.25, DECnet, LAT, are all methods of encapsulation of information into discrete units and their subsequent delivery. Some are part of the PSTN, and some are not. Each protocol has its set of restrictions/features. None are "bad" per se (not even X.25, Joel ;) Make sure not to confuse the protocol with the medium it uses. For instance, frame-relay DS3s will outperform ATM DS1s for data and voice routing :)* Many people who "hate" frame-relay really despise the predominant practice of overselling non Committed-Information-Rate circuits into an overloaded central hub location. Frame-Relay "routing" is L2, and IP routing is L3, so I won't really go into comparing them any more than, say, discussing the technical advantages of TCP vs. IP. They are two different things with similar form yet different functions. Ehud * There are some purists who would claim that the additional overhead of switching frame-relay packets would increase latency over that inherent in an ATM switched network. They would say that my example above (which is just an example, so reading too much into it is an exercise in being a pedant) is flawed because the frame-DS3 is more latent than the ATM-DS1. Nonetheless I claim the inherent latency of both networks to be less than that noticeable by human ears. Nya. Nee. Nya. Nee. PooPoo.
I've noticed that several of the larger networks use frame-relay.
Why? Our experience with frame-relay with the local telco has had mixed results.
What technical advantages does a frame-relay network have over an IP routed network?
Thanks!
Joe