[ns] Sending "Destination Unreachable" to the application in Ad-Hoc Netoworks(AODV)

[G�ran Nylen <gurra@ipunplugged.com>]

Hi everyone!

I'm currently doing some work on AODV. Acording to the aodv draft, the 
routing agent should send a "destination unreachable" message to the 
application if a RREP isn't received after a maximum of RREQ_RETRIES.

How would I implement this in NS? That is, how can I in aodv.cc tell the 
"application" in the higher layer to stop sending?

It is of importance to implement this, since otherwise will the network be 
flooded with RREQ's which shouldn't been sent! 

This is not handled by the Mahesh AODV implementation, nor in the current 
NS-2 v2.1b8a AODV implementation. In both implementations, the counter which 
is used to check how many RREQ's has been sent without receiving a RREP, is 
just being reseted to zero when it reaches RREQ_RETRIES. Thus, resulting in 
that new RREQ's can be sent out again, and this scenario loops forever.

Regards,
G�ran