Hi, thank you so much for your answers! I will try to disable ARP packet transmissions. Thank you also for the explanation, I was trying to debug p802_15_4mac but it is not so easy... I forced the queue to send packet modifying the recv function in the file queue.cc, adding a counter and calling the resume function after a certain number of attempts, also with the blocked flag true. It is not so elegant but it helped me to understand something more!
Regards Cesare Carretti > Hi there, > > this failure should most probably relate to the busy_rx state returned > after the call to switch the radio to transmit. > This happens basically in two different situations, > one is during the association and the other one is during sending/CCA. > If during the CCA a packet arrives, this packet gets falsely received and > thus, upon the call to switch, the function to switch the radio state > returns with a busy_rx, that doesn't get handled and thus the whole > sending process gets stuck. As there is still the outgoing packet within > the mac, the enforcement of an additional sending - by the way, how did > you manage/implement that one? - leads to a task overflow. > > The arp only diminishes the probability of this failure happening, as it > shortens the time for packet processing at the node... > > > > -------- Original-Nachricht -------- >> Datum: Thu, 18 Oct 2007 18:11:48 +0200 >> Von: Stefano Busanelli <[EMAIL PROTECTED]> >> An: "Cesare M. Carretti" <[EMAIL PROTECTED]> >> CC: ns-users@ISI.EDU >> Betreff: Re: [ns] Bug in 802.15.4? > >> >> >> In the past I'd had noticed a similar strange behavior: in fact, during >> some simulation runs, nodes didn't transmit packets, seemingly without >> no reason, while in other simulations nodes transmitted normally. >> >> I had solved the problem disabling ARP packet transmissions. >> In the mailing list archive there are many threads that explain how to >> do this. >> >> Regards >> >> Stefano Busanelli >> >> Il giorno gio, 18/10/2007 alle 12.33 +0200, Cesare M. Carretti ha >> scritto: >> > Hello all, >> > I am implementing a distributed algorithm for sensor network, and I >> wrote >> > an application and a transport protocol simil-UDP to send data. >> > I have a strange problem in my simulation: >> > at some point, one node stop to send packet, it is blocked and if I >> try >> to >> > force the queue to send packet, I have a task overflow error from mac >> > layer. >> > I still do not know why this thing happen at some point, I am trying >> to >> do >> > some debugging, maybe for some collision. Anyway I think this is not >> > normal, because it should never happen that a node stop sending data >> (it >> > continues to receive) at all forever, it should maybe reset itself if >> > there is some problem. Maybe it is waiting for something? >> > My application works very well over 802.11, so I think it should be >> the >> > same with 802.15.4 (of course with a different output, number of >> packet >> > etc). >> > However it shouldn't stop! >> > >> > What do you think? >> > >> > best regards >> > >> > Cesare Carretti >> > > > -- > GMX FreeMail: 1 GB Postfach, 5 E-Mail-Adressen, 10 Free SMS. > Alle Infos und kostenlose Anmeldung: http://www.gmx.net/de/go/freemail >
