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snoop.tcl produces same output with different error rates




Hi,

Actually this problem was pointed out earlier by Amit Saxena and Ramesh
Neelamani before too. (see
http://www-mash.cs.berkeley.edu/dist/archive/ns-users/9711/0070.html and
http://www-mash.cs.berkeley.edu/dist/archive/ns-users/9711/0068.html )

Though Amit had used too high error rate (once every 1 ms), Ramesh had
used snoop.tcl properly. Now I am again raising question about the same
problem.

I tried to run ns with snoop.tcl with following 3 commands several times.
-------
ns snoop.tcl -e 10 -eu pkt -stop 20 -ll Snoop -r
ns snoop.tcl -e 100 -eu pkt -stop 20 -ll Snoop -r
ns snoop.tcl -e 10 -eu pkt -stop 20 -r
-------
And surprisingly it produced almost similar out and tcp.tr files. With
ending portions like output attached at the end of this mail. Why same
throughput and similar "out" and "tcp.tr" files?

And I *DOUBT* that any error was generated because their was no letter "l"
in the first column of file "out" anywhere, which should be there if there
was any loss. (I even run the same commands with "-stop 100" but did not
get any loss, i.e. no "l" in first column)

And if that is the case, no wonder why the output for all the three
commands are almost same - whether you have loss of 1 pkt in 10 or 1 in
100 and whether you have snoop enabled or not. 

Any suggestions? (Hari, Giao, Kannan, Kevin or any one else?)

Thanking you,

Miten.

---------
[mozart] ~/ns/ns-2/tcl/ex/snoop >tail out
r 19.9975 0 1 tcp 1000 ------- 0 2.0 1.0 4357 8696
+ 19.9975 1 0 ack 40 ------- 0 1.0 2.0 4357 8733
- 19.9975 1 2 ack 40 ------- 0 1.0 2.0 4357 8733
r 19.998 1 0 ack 40 ------- 0 1.0 2.0 4356 8731
+ 19.998 0 2 ack 40 ------- 0 1.0 2.0 4356 8731
- 19.998 0 2 ack 40 ------- 0 1.0 2.0 4356 8731
r 19.9991 0 2 ack 40 ------- 0 1.0 2.0 4356 8731
+ 19.9991 2 0 tcp 1000 ------- 0 2.0 1.0 4376 8734
- 19.9991 2 0 tcp 1000 ------- 0 2.0 1.0 4376 8734
- 19.9994 0 1 tcp 1000 ------- 0 2.0 1.0 4359 8700
3:00 [mozart] ~/ns/ns-2/tcl/ex/snoop >tail tcp.tr
19.98985 2  0  1  0  t_seqno_ 4375
19.98985 2  0  1  0  maxseq_ 4374
19.99426 2  0  1  0  ack_ 4355
19.99426 2  0  1  0  cwnd_ 95.266
19.99426 2  0  1  0  t_seqno_ 4376
19.99426 2  0  1  0  maxseq_ 4375
19.99906 2  0  1  0  ack_ 4356
19.99906 2  0  1  0  cwnd_ 95.276
19.99906 2  0  1  0  t_seqno_ 4377
19.99906 2  0  1  0  maxseq_ 4376
3:00 [mozart] ~/ns/ns-2/tcl/ex/snoop >
----------------




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Miten N. Mehta                                 	Graduate Research Assistant 
3902, Collegemain, #908				Computer Science
Bryan, 						Texas A & M University
Texas-77801.					College Station, TX-77843

Tel.#(409) 846 1451                            	(409) 845 5007 
			E-mail# [email protected]
            Home Page : http://www.cs.tamu.edu/people/mmehta

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	"UNTIL YOUR DREAMS COME TRUE, KEEP ON WORKING FOR THAT"

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