But you can configure PVC's with ATM, working with an ATM
cloud, similar to frame relay, no? And if this is the case, then
a large backbone-type provider may desire to set up an ATM cloud,
making it easy to add POP's (just add them to the cloud), and allow
for more layer 2 routing (just configure PVC's between every POP you
have, building a full web, and a traceroute would now travel 2 or 4
hops instead of 12...?)

If the number of hops that shows up in a traceroute is a design parameter
when building a network. And that is concidered higher than the overall
performance, yes.. IP over IP tunnels would also solve the problem -:slight_smile:

(or disable loop detection by taking out the TTL decrement -:slight_smile:

  instead of some sort of hierarchichal star topology, you'd
have a large web...

Your ATM network topology will still likely be looking like what your IP
network would have looked, right?

In order to make efficient use of your cloud, all routers has to
be neighbours to all other routers, so in practice there is a limit to
the number of routers you can have.

Many large IP-networks are still built as logical star networks.

Depending on the size of your IP network, a lot of traffic will be
in/outbound to other ISP's, and here you need a router for various

  and one more potential benefit to ATM -- won't it scale
very well to OC-12? ie, when you want to upgrade your network to
OC-12, you'd have no changes to make?

Asuming everyone talks to everyone, but, what router do you connect
at the edge that speaks OC-12? Or do you have many small OC-3 routers?


Now, that's a thought! :wink:

Michael Dillon Voice: +1-604-546-8022
Memra Software Inc. Fax: +1-604-546-3049
http://www.memra.com E-mail: michael@memra.com