Routing does not use an exponential NP-Complete algorithm (like the

travelling salesman). The travelling salesman problem tries to solve the

cheapest way in which a salesman can visit every one of a set of cities.

In fact, routing can be done in order (n) with a bounded metric and

bounded distance, since it really is only trying to find the cheapest way

to get to a single destination.

What I don't know, is why is it that SS7, the telephone routing protocol,

can do some of the things that are required, like load sharing across

unequal paths, for example. Does anyone have any insight into this?

--Neal

Avi Freedman <freedman@netaxs.com> 11/09/96 05:31am >>>

I understand that IOS 12.0 will solve the travelling salesman problem

for arbitrary number of cities. Seems they had to find a way to solve

NP-complete problems in sub-exponential time in order to give us better

algorithms for guaranteed-optimal routing.

Anyway, sorry to be snide - any suggestions you have about algorithms

for exchanging routing data between (or inside of) providers that also

takes into account link size and perhaps hop-count, as opposed to

just AS-PATH, are welcome at the next IETF meeting.

Avi