IFQ drops problem in ns2.35

Rita Ahmad · 05-17-2018, 07:44 PM

I have my own routing protocol, which has been built using ns2.35 and Ubuntu 14.04. Previously, I used to run an 80 seconds simulation for 10 flows of CBR packets (0.2 interval) over UDP with 54Mbps data rate.The PDR value collected from an awk file was perfect with no drops at all. Currently, I'm running a 30 seconds simulation for 9 flows of CBR packets (0.01 interval) over UDP with 24Mbps data rate, but it gives me a bad PDR value that sometimes reaches 2% because of the many IFQ drops in the trace file despite the successful sending of the AGT packets. Increasing the ifq length or the queue of the protocol itself does not make any changes.

Any idea about the problem I'm facing knowing that the ARP has already been disabled?

knudfl · 05-18-2018, 12:58 PM

First : The awk scripts are not 100% reliable.
Sometimes a script works with a few trace files only.

**** PacketDeliveryRatio ****
Naveem-PDR.awk
PacketDeliveryRatio.awk
PDR-2.awk
pdr.awk
PDR.awk
pdr.pl
PDR_zhibinwu.awk

**** Packets dropped ******
drop.awk
droppackets.awk
packet-drop.pl
packets-dropped-received.awk
thr_drop_delay.awk
All ~240 ns2 scripts https://drive.google.com/drive/folde...7T?usp=sharing

`ns2 drop packets´ https://www.google.com/webhp?hl=all&...2+drop+packets

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Rita Ahmad · 05-18-2018, 03:53 PM

Thanks a lot for your reply. Actually, the drops appear in the trace file as follows(showing a part of the trace file):

Code:

s 27.830000000 _3_ AGT  --- 7090 cbr 512 [0 0 0 0] [energy 997.334407 ei 0.000 es 0.000 et 0.274 er 2.391] ------- [3:1 4:0 32 0] [783] 0 0
r 27.830000000 _3_ RTR  --- 7090 cbr 512 [0 0 0 0] [energy 997.334407 ei 0.000 es 0.000 et 0.274 er 2.391] ------- [3:1 4:0 32 0] [783] 0 0
s 27.830000000 _4_ AGT  --- 7091 cbr 512 [0 0 0 0] [energy 996.961839 ei 0.000 es 0.000 et 0.703 er 2.335] ------- [4:1 5:0 32 0] [783] 0 0
r 27.830000000 _4_ RTR  --- 7091 cbr 512 [0 0 0 0] [energy 996.961839 ei 0.000 es 0.000 et 0.703 er 2.335] ------- [4:1 5:0 32 0] [783] 0 0
s 27.830000000 _5_ AGT  --- 7092 cbr 512 [0 0 0 0] [energy 996.790097 ei 0.000 es 0.000 et 0.350 er 2.860] ------- [5:1 6:0 32 0] [783] 0 0
r 27.830000000 _5_ RTR  --- 7092 cbr 512 [0 0 0 0] [energy 996.790097 ei 0.000 es 0.000 et 0.350 er 2.860] ------- [5:1 6:0 32 0] [783] 0 0
s 27.830000000 _6_ AGT  --- 7093 cbr 512 [0 0 0 0] [energy 998.030771 ei 0.000 es 0.000 et 0.439 er 1.530] ------- [6:1 7:0 32 0] [783] 0 0
r 27.830000000 _6_ RTR  --- 7093 cbr 512 [0 0 0 0] [energy 998.030771 ei 0.000 es 0.000 et 0.439 er 1.530] ------- [6:1 7:0 32 0] [783] 0 0
s 27.830000000 _7_ AGT  --- 7094 cbr 512 [0 0 0 0] [energy 996.387846 ei 0.000 es 0.000 et 0.743 er 2.869] ------- [7:1 8:0 32 0] [783] 0 0
r 27.830000000 _7_ RTR  --- 7094 cbr 512 [0 0 0 0] [energy 996.387846 ei 0.000 es 0.000 et 0.743 er 2.869] ------- [7:1 8:0 32 0] [783] 0 0
s 27.830000000 _8_ AGT  --- 7095 cbr 512 [0 0 0 0] [energy 996.254195 ei 0.000 es 0.000 et 1.122 er 2.624] ------- [8:1 9:0 32 0] [783] 0 0
r 27.830000000 _8_ RTR  --- 7095 cbr 512 [0 0 0 0] [energy 996.254195 ei 0.000 es 0.000 et 1.122 er 2.624] ------- [8:1 9:0 32 0] [783] 0 0
s 27.830000000 _0_ RTR  --- 7087 cbr 545 [0 0 0 0] [energy 997.553137 ei 0.000 es 0.000 et 0.585 er 1.862] ------- [0:1 1:0 31 1] [783] 0 0
s 27.830000000 _2_ RTR  --- 7089 cbr 545 [0 0 0 0] [energy 997.091421 ei 0.000 es 0.000 et 0.265 er 2.643] ------- [2:1 3:0 31 7] [783] 0 0
s 27.830000000 _3_ RTR  --- 7090 cbr 545 [0 0 0 0] [energy 997.334407 ei 0.000 es 0.000 et 0.274 er 2.391] ------- [3:1 4:0 31 12] [783] 0 0
s 27.830000000 _4_ RTR  --- 7091 cbr 545 [0 0 0 0] [energy 996.961839 ei 0.000 es 0.000 et 0.703 er 2.335] ------- [4:1 5:0 31 13] [783] 0 0
s 27.830000000 _5_ RTR  --- 7092 cbr 545 [0 0 0 0] [energy 996.790097 ei 0.000 es 0.000 et 0.350 er 2.860] ------- [5:1 6:0 31 12] [783] 0 0
s 27.830000000 _6_ RTR  --- 7093 cbr 545 [0 0 0 0] [energy 998.030771 ei 0.000 es 0.000 et 0.439 er 1.530] ------- [6:1 7:0 31 15] [783] 0 0
s 27.830000000 _7_ RTR  --- 7094 cbr 545 [0 0 0 0] [energy 996.387846 ei 0.000 es 0.000 et 0.743 er 2.869] ------- [7:1 8:0 31 8] [783] 0 0
s 27.830000000 _8_ RTR  --- 7095 cbr 545 [0 0 0 0] [energy 996.254195 ei 0.000 es 0.000 et 1.122 er 2.624] ------- [8:1 9:0 31 9] [783] 0 0
D 27.830025000 _3_ IFQ  --- 7090 cbr 545 [0 c 3 800] [energy 997.334407 ei 0.000 es 0.000 et 0.274 er 2.391] ------- [3:1 4:0 31 12] [783] 0 0
D 27.830025000 _5_ IFQ  --- 7092 cbr 545 [0 c 5 800] [energy 996.790097 ei 0.000 es 0.000 et 0.350 er 2.860] ------- [5:1 6:0 31 12] [783] 0 0
D 27.830025000 _6_ IFQ  --- 7093 cbr 545 [0 f 6 800] [energy 998.030771 ei 0.000 es 0.000 et 0.439 er 1.530] ------- [6:1 7:0 31 15] [783] 0 0
D 27.830025000 _7_ IFQ  --- 7094 cbr 545 [0 8 7 800] [energy 996.387846 ei 0.000 es 0.000 et 0.743 er 2.869] ------- [7:1 8:0 31 8] [783] 0 0
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waiting for your kind feedback.

knudfl · 05-19-2018, 05:00 AM

Packet drops will appear when the packets are in a queue too long, AFAIK.

Not much change is to be done to a simulation.tcl to create an entirely new situation.
... Or may be your first file.tcl with "80 seconds simulation for 10 flows" was pure luck?

Please try out some other combinations ... also with various node numbers.

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