[ns] Wireless simulations
Gautam - Chakrabarti
chakra10@msu.edu
Thu Apr 18 12:25:01 2002
OK, I think I got the problem, most probably no data packet was dropped,
I am familiar with dsr, tracing may be a bit different in AODV, but
going by the dsr way, I feel there was NO drop of data pkts, the 1 drop
must be a control pkt, check that from the line that marks the drop
event, it should give the type of pkt and u would understand if it is a
data pkt or aodv control pkt.
Again going by the dsr tracing way, when u r counting sents and recs, u
need to count only the AGT trace, if u look INTO the trace u will find
the other sents & recs are to/from intermediate nodes, u don't want to
count these, right ?
U may want to look up the site on the monarch project in rice univ( just
moved from cmu ), they have a manual which shows where exactly they put
the tracers, i.e. in what levels.
NOTE u need to verify the above info/someone familiar with aodv needs to
verify it, since I know tracing in DSR is a bit different than the
others.
NOTE, ur total sents/recs/drops will contain control packets also,
probably u r more interested in data pkts, so u need to filter those
out.
hth,
gautam
"Monique M. Morin" wrote:
>
> Here's the breakdown of what I am seeing.....again, I am new and don't
> understand all of this, so let me know anything that I may be missing here....
>
> I do not have a trace analyzer script -- I am looking directly at the .tr file
> generated by NS.
> I have 3 nodes in a row and I am sending 1 packet from "nodeA" to "nodeC".
> I am allowing plenty of time (no "Nw END" present).
> I am using AODV & Mac/802_11 (with bandwidth set to 1 mb).
> Packet size 512 with max packets being 1.
> UDP and Null agents at the source and destination.
> I have router, MAC, and agent tracing turned on.
>
> 18 sents (1 AGT, 3 RTR, 14 MAC)
> 21 recs (1 AGT, 4 RTR, 16 MAC)
> 1 drop (1 RTR)
>
> The drop I don't have a clue about -- the cause is TTL, but that doesn't make
> sense to me with only 3 nodes!
>
> Any comments welcome,
>
> -- Monique
>
> Gautam - Chakrabarti wrote:
>
> > Yeah, that's right, but I think a simple way to check if your
> > trace-analyzer is correct is to check the following: if what Venkatesh
> > had said was correct, then there should be "that many number" of packets
> > which haven't ever been received (& not dropped). SEARCH ur trace file
> > to see if that is correct, that is if there is NOT a 'receive' event at
> > the destination for those pkts.
> >
> > So pkts sent should either be dropped OR received OR (no drop & no final
> > receive event --> this can be due to the scenario pointed by Venkatesh
> > or some problem with the protocol, e.g. not "properly" dropping a
> > packet).
> >
> > gautam
> >
> > Vikram Kanodia wrote:
> > >
> > > How much is teh difference.....?
> > >
> > > if its 1 or two packets then as Venkatesh pointed out could be packets in
> > > air....if its more than that then something is seriously wrong (or there
> > > is an error in your trace-analyzer script).....
> > >
> > > Curious to know the answer.....
> > >
> > > -V
> > >
> > > >
> > > > Hi Morin,
> > > >
> > > > I would attribute the discrepancy in the numbers to the packets that are
> > > > just sent almost at the end of simulation. These packets are in the air,
> > > > and are neither received nor dropped due to the stop of simulation. This
> > > > might be the case.....
> > > >
> > > > Venkatesh.......
> > > >
> > > >
> > > > On Wed, 17 Apr 2002, Monique M. Morin wrote:
> > > >
> > > > >
> > > > > I just started doing wireless simulations also and in
> > > > > a VERY simple scenario (1 packet) the received
> > > > > packets and the dropped packets do NOT equal the
> > > > > sent packets.
> > > > >
> > > > > I have the agent, router, and mac traces turned ON in
> > > > > the node config, so I shouldn't be missing any activities.
> > > > >
> > > > > Anyone have any ideas why the numbers don't seem to
> > > > > add up?
> > > > >
> > > > > Thanks!
> > > > >
> > > > > -- Monique
> > > > >
> > > > >
> > > > >
> > > > > > > > 2. Do Packets received and packets dropped add up to
> > > > > > > > packets sent?
> > > > > > >
> > > > > >
> > > > > > Yeah, SHOULD BE.
> > > > > >
> > > > > > > I would think that this would be true. You could
> > > > > > > verify it by analyzing a trace file. Be careful about
> > > > > > > the levels of the traces though. Packets could be
> > > > > > > dropped at the RTR and/or MAC layers.
> > > > > > >
> > > > > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > > --
> > >
> > > Department of ECE, Rice University | 713 348 3786 (O)| 713 664 5650(H)
> > > WWW: http://www.ece.rice.edu/~kanodia
> >
> > --
> > ***************************************************************
> > Gautam Chakrabarti
> > MS Student
> > Computer Sc. and Engg Department
> > Michigan State University
> >
> > Email : chakra10@msu.edu
> > Home Page : http://www.cse.msu.edu/~chakra10
> >
> > Why is there so much month left at the end of the money?
> > --- John Barrymore
> > ***************************************************************
--
***************************************************************
Gautam Chakrabarti
MS Student
Computer Sc. and Engg Department
Michigan State University
Email : chakra10@msu.edu
Home Page : http://www.cse.msu.edu/~chakra10
Why is there so much month left at the end of the money?
--- John Barrymore
***************************************************************