[ns] Wireless topology, Packets Getting Dropped, reason IFQ

["Niko A. Fikouras" <nemo@comnets.uni-bremen.de>]

Hi all,

I am trying to simulate a cbr communication between a Mobile Node (node
1)
and a Home Agent (node 0).

I get the following output trace:

r 0.000000000 _1_ RTR  --- 0 cbr 210 [0 0 0 0] ------- [1:2 0:2 32 0]
[0] 0 0
r 0.000007826 _0_ RTR  --- 1 udp 48 [0 0 0 0] ------- [0:0 -1:0 32 0]
r 0.003750000 _1_ RTR  --- 2 cbr 210 [0 0 0 0] ------- [1:2 0:2 32 0]
[1] 0 0
s 0.005335499 _0_ RTR  --- 1 udp 68 [0 0 0 0] ------- [0:0 -1:0 32 0]
r 0.005915512 _1_ RTR  --- 1 udp 68 [0 ffffffff 0 800] ------- [0:0 -1:0
32 0]
r 0.005915512 _1_ RTR  --- 3 udp 52 [0 0 0 0] ------- [1:0 0:0 32 0]
r 0.007500000 _1_ RTR  --- 4 cbr 210 [0 0 0 0cmu-trace.h ] ------- [1:2
0:2 32 0] [2] 0 0
r 0.011250000 _1_ RTR  --- 5 cbr 210 [0 0 0 0] ------- [1:2 0:2 32 0]
[3] 0 0
r 0.015000000 _1_ RTR  --- 6 cbr 210 [0 0 0 0] ------- [1:2 0:2 32 0]
[4] 0 0
D 0.015000000 _1_ RTR  IFQ 0 cbr 230 [0 0 0 0] ------- [1:2 0:2 32 0]
[0] 0 0
r 0.018750000 _1_ RTR  --- 7 cbr 210 [0 0 0 0] ------- [1:2 0:2 32 0]
[5] 0 0
D 0.018750000 _1_ RTR  IFQ 2 cbr 230 [0 0 0 0] ------- [1:2 0:2 32 0]
[1] 0 0

As can be seen from the above trace  none of the cbq packets actually
manages to get through to
node 0 (receiver).  Moreover, it can be seen that the reason for the
packet drop is IFQ.
I have checked out the meaning of IFQ in "cmu-trace.h" and apparently it
means that there is
no more buffer space in IFQ  left. As such I have tried to increase my
"ifqlen" but nevertheless the
situation has not improvement at all. The same behaviour is observered
for all cbq packets
untill the end of the simulation.

While I am at it, I might further ask: You might also observe that in
the above trace there are several
udp packets. I presume that several of them are signaling generated by
the ad-hoc routing algorithm.
I wish in my tests to use native 802.11 without the presence of any
routing signalling. How may I
turn these messages off.

Any response will be appreciated

Thanks in advance,

Niko