In the standard AM message interface there is a queue length of 1... When receive returns the message pointer that it got, that buffer can be used for a new message reception. I think if anything comes in before that it gets dropped, but I would have to look through all the code to verify. I never looked into why the 10ms throttling had such a dramatic effect on success rates.
MS Kartik Siddhabathula wrote: > Thanks Michael for sharing the report. > > I know that we do loose messages, in one of my experiment, I did the > packet delivery rate test and I found that I lost somewhere between 1 to > 11 messages and that is something we are not discussing about as that is > acceptable to both me and Harshwal. > > The reason why I had posted the query in the forum and Harshwal > re-posted it is that we wanted to know about the buffer queue size in > the receiving end. In one of my experiments, I had one sender and one > receiver. Sender transmitted 100 messages continuously through periodic > timer fired at 0 ms. I found that in my receiving end I was receiving > some where around 30 messages only and that means 70 messages were lost > and that's why this thread. > > Kartik > > --- On *Mon, 7/19/10, Michael Schippling /<[email protected]>/* wrote: > > > From: Michael Schippling <[email protected]> > Subject: Re: [Tinyos-help] [*] Regarding sending and receiving > To: "Kartik Siddhabathula" <[email protected]> > Cc: [email protected], "TinyoS help" > <[email protected]> > Date: Monday, July 19, 2010, 12:07 PM > > Messages will be lost. Get over it... > > The number will vary depending on the distance > between motes, and whether they can all "hear" > each other (see Hidden Node Problem). I think > TOSSIM has a whole modeling system for testing > message failures, but I've never used the sim. > > I also found that throttling sends with up to 10ms > between them helped greatly in small systems. See > this old report: > http://www.etantdonnes.com/Motes/report_mica2/ > > MS > > Kartik Siddhabathula wrote: > > Hi Harshal, > > > > As from your output it is clear that the receiver mote is able to > get the messages. > > The problem must be in the simultaneous sending. The problem I > faced was also when I was sending simultaneously that's why I wanted > to know what is the buffer size for receiving. > > > > As far as I my understanding goes, the reason must be that when > the receiver receives the messages, it keeps in the buffer till it > is processed (crc check etc). While it is processing a packet and > another one arrives it puts them in the buffer queue. > > > > Kartik > > > > --- On *Mon, 7/19/10, [email protected] > </mc/[email protected]> /<[email protected] > </mc/[email protected]>>/* wrote: > > > > > > From: [email protected] > </mc/[email protected]> <[email protected] > </mc/[email protected]>> > > Subject: Re: [*] [Tinyos-help] Regarding sending and receiving > > To: "Kartik Siddhabathula" <[email protected] > </mc/[email protected]>> > > Cc: [email protected] > </mc/[email protected]> > > Date: Monday, July 19, 2010, 3:50 AM > > > > Hi Kartik, > > Thanks for your reply. I did what you suggested and got the > > following output: > > X=91 > > X=94 > > X=86 > > X=90 > > X=83 > > X=88 > > X=77 > > X=86 > > X=89 > > X=89 > > > > According to this, most packets are received, which is good. > However, in > > my application I am still facing the same problem. In that > app, many > > nodes > > try to send at a time to a particular node. More concretely, > in (TOSSIM > > simulation of) a 25 node network, about 20 nodes send a > message to a > > particular node of which only 7-8 are seen to be received by > it. Could > > this simultaneous sending be a reason for that node to not to > > receive all > > the messages? > > > > Regards, > > Harshal > > > > > > > Hi Harshal, > > > > > > I got over the problem. I tested some code two days back and I > > found that > > > I was receiving some where between 89 to 99 messages out > of 100 > > messages. > > > I am not sure how I overcame the problem though I hadn't made > > much changes > > > to the code! > > > > > > Try to do this: Have one sender and one receiver. > > > Sender sends 1000 messages and each message is a number > one more > > than the > > > previous one. > > > > > > At the receiver have two variables X and Y initialized to 0. > > > let's say the received number is z, > > > do if z<Y+100 then X++ > > > else save the value of X in the log and then do X=0 and > Y=Y+100. > > > > > > Get the log and then let me know the results. > > > > > > Kartik > > > > > > > > > --- On Sun, 7/18/10, [email protected] > </mc/[email protected]> > > </mc/[email protected] > </mc/[email protected]>> <[email protected] > </mc/[email protected]> > > </mc/[email protected] > </mc/[email protected]>>> > > > wrote: > > > > > > From: [email protected] > </mc/[email protected]> > > </mc/[email protected] > </mc/[email protected]>> <[email protected] > </mc/[email protected]> > > </mc/[email protected] > </mc/[email protected]>>> > > > Subject: Re: [*] [Tinyos-help] Regarding sending and > receiving > > > To: "Kartik Siddhabathula" <[email protected] > </mc/[email protected]> > > </mc/[email protected] > </mc/[email protected]>>> > > > Cc: [email protected] > </mc/[email protected]> > > </mc/[email protected] > </mc/[email protected]>> > > > Date: Sunday, July 18, 2010, 11:46 PM > > > > > >> Hi All, > > >> > > >> I have a question regarding the buffers. I am using > tinyos-2.x and > > > telosb > > >> motes. From one mote I sent a message 100 times, but another > > mote which > > > was configured to receive the messages received less messages. > > >> > > >> Once it received the message only thrice and the maximum > is 57 > > messages. > > > The no of messages received (on average) is 30. > > >> > > >> What could be the reason, any ideas? > > >> > > >> Thanks in advance, > > >> Kartik > > >> > > >> > > >> > > >> _______________________________________________ > > > > > > > > > Hi, > > > I am facing a similar problem to the one above. It would be > > really great > > > if someone provides some pointers. > > > > > > Regards, > > > Harshal > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Tinyos-help mailing list > > [email protected] > </mc/[email protected]> > > > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
