OSPF multi-level hierarchy: Necessary at all?

Fri May 28 01:47:18 UTC 1999

Tony Li <tony1 at home.net> wrote:

>> There's a better solution: decrease the number of nodes by replacing
>> clusters with bigger boxes.  This has an additional advantage of reducing
>> number of hops (and, consequently, latency variance).

>Certainly that helps, but as we move forward you still end up with lots of
>boxes in the network simply because you're in many different geographic
>locations.

Well, actually it is not that bad.  The biggest number of locations is
probably found in AT&T phone network - 250 or so.  Sprint is in few
dozen.  The existing IGPs are quite happy with that kind of complexity,
so if you belong to the "one-router-per-POP" school of thought the
IGP complexity is a non-issue.

--vadim