Bug 392 – Example star.cc confuses TCP

Bug 392 - Example star.cc confuses TCP


Summary:	Example star.cc confuses TCP

Status:	RESOLVED FIXED

Product:	ns-3
Classification:	Unclassified
Component:	internet
Version:	ns-3-dev
Hardware:	All All

Importance:	P1 normal
Assigned To:	Rajib Bhattacharjea

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2008-10-24 20:36 EDT by Craig Dowell
Modified:	2008-12-06 03:13 EST (History)
CC List:	1 user (show)

See Also:

Attachments
Proposed fix (737 bytes, patch) 2008-12-01 11:52 EST, Rajib Bhattacharjea	Details \| Diff
Add an attachment (proposed patch, testcase, etc.)

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Description Craig Dowell 2008-10-24 20:36:06 EDT

Change the ns3::OnOffApplication::DataRate on line 54 of example/star.cc to 15kb/s as in,

Config::SetDefault ("ns3::OnOffApplication::DataRate", StringValue("15kb/s"));

TCP gets confused, and the simulation doesn't stop.

A tcpdump shows (at the supposed end end of the simulation)

9.843352 IP 10.1.1.2.49153 > 10.1.1.1.50000: . 16441:16578(137) win 65535
9.916419 IP 10.1.1.2.49153 > 10.1.1.1.50000: . 16578:16715(137) win 65535
9.916419 IP 10.1.1.1.50000 > 10.1.1.2.49153: . ack 16715 win 65535
9.989486 IP 10.1.1.2.49153 > 10.1.1.1.50000: . 16715:16852(137) win 65535
10.000000 IP 10.1.1.1.50000 > 10.1.1.2.49153: F 1:1(0) win 65535
10.004134 IP 10.1.1.2.49153 > 10.1.1.1.50000: . ack 2 win 65535
10.144326 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
10.144326 IP 10.1.1.1.50000 > 10.1.1.2.49153: . ack 16853 win 65535
10.189486 IP 10.1.1.1.50000 > 10.1.1.2.49153: . ack 16853 win 65535
10.454007 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
11.073370 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
12.312094 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
14.789542 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
19.744439 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
29.654233 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
39.564027 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
49.473821 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
59.383616 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
69.293410 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
79.203204 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
89.112998 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535
99.022792 IP 10.1.1.2.49153 > 10.1.1.1.50000: F 16715:16852(137) win 65535

and this goes on "forever" ...

Comment 1 Rajib Bhattacharjea 2008-12-01 11:52:05 EST

Created attachment 322 [details]
Proposed fix

This fixes the issue, but I require some feedback from George as to the "correctness" of the fix.  I hope to have an answer this afternoon.

Comment 2 Rajib Bhattacharjea 2008-12-03 11:07:44 EST

George agrees that this looks good.  I am doing some testing to make sure that this doesn't break things...