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[ns] trace for packet drop



Hi, there,
   I have a wierd record entry for packet drop in my trace file. Please
see the wierd trace entry and its explanation at the end. 
My question is that can I trust the trace file? where can I add some code
or to trace in debugger to verify that it really write the corrrect
information to the trace file? since except wierd trace record,
everything else seems normal in my simulation, I suspect the trace entry
is not correct..
Thanks in advance!
yan


--------------------------
the topology is 
2(FH) == 0(BS) -- 3(LAN) - -- 1 (MH)

the traffic is from 2-->1, but the record for drop is something like

d 4.855052 1 3 tcp 1000 ------- 0 2.0 1.0 783 1576

the 3rd field "1" means src in MAC layer header,
the 4th field "3" means dst in MAC layer header,
2 in "2.0" means  packet src(end-to-end src, different from MAC layer,
hop src)
1 in "1.0" means  packet dst(end-to end dst) 
              
the wierd thing is that data packet should go from 3-->1 instead of
"1-->3" in the trace. From my understanding, the correct trace entry for
"drop"  should be the 3rd and 4th field is switched, since the data pkt is
going from 2-->1, so it should be:

d 4.855052 3 1 tcp 1000 ------- 0 2.0 1.0 783 1576