Subject: AODV questions

From: "Salavat R. Magazov \(BT\)" <[email-masked]>
Date: Thu, 6 Jul 2000 12:54:27 +0400

Hello

I have some questions regarding AODV. Sequence numbers in particular.

Let's imagine the situation where node S (source) tries to find a route to
node D (destination) using destination sequence number n. Say there are four
other participating nodes 1, 2, 3 and 4 through which route lies.
S-->1-->2-->3-->4-->D
 After the route is found the source starts transmitting, etc. Suddenly the
connection, say, between 2 and 3 breaks for whatever reason, then RERR
message is sent upstream to notify nodes of broken link. Let's also assume
that route entry for D in nodes from 3 through D did not expire yet.
S-x->1-x->2-x->3-->4-->D
After S gets RERR message it will try to find another route to D, and as
specification says uses n+1 as a dest. seq. number to be sure that new route
is established. This is the point I do not understand. Why not to use n and
thus use the part of the route from 3 to D which is still available? The
nodes could save time and bandwidth. Due to the movement of nodes there may
emerge another shorter route which will be used as soon as S is notified
about its existence by receiving RREP with smaller hop count.

Disclaimer:
I am not saying that what you offer is bad, I rather say I do not understand
the reason.

Regards
Salavat