Ax autoroutes

[brian@ucsd.Edu (Brian Kantor)]

It's clear to me that this is a bug, perhaps in design but more likely
in implementation.  Any autorouter of this kind should immediately
ignore the old route and use the currently-in-use route on a reply to
an incoming connection request.

It is argueable that it should forget and relearn in such a
circumstance.  Perhaps a better trick is to remember two or more routes
in a stack and when initiating an outgoing connection, try them all in
turn, discarding unsuccessful ones.  That would handle varying
propagation, I think.

I've suggested a similar sort of route-unlearning algorithm for revised
net/wrong routing:  when you (as a NR node) hear a nodes broadcast, you
immediately open up an AX.25 link to the station doing the broadcast.
If your link fails for any reason (including retrying-out on
keepalives), you flush that neighbor from the NR routes table, perhaps
taking some number of nodes with it.  There is little overhead with
this technique, just a few one-packet keepalives a couple of times an
hour - perhaps every 15 minutes or so.
        - Brian