Bug 2761 – Packet has no Traffic ID for CTS frames when A-MPDU is used

Bug 2761 - Packet has no Traffic ID for CTS frames when A-MPDU is used


Summary:	Packet has no Traffic ID for CTS frames when A-MPDU is used

Status:	RESOLVED FIXED

Product:	ns-3
Classification:	Unclassified
Component:	wifi
Version:	ns-3.26
Hardware:	All All

Importance:	P3 normal
Assigned To:	sebastien.deronne

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2017-06-25 12:09 UTC by Varun Reddy
Modified:	2017-07-02 09:45 UTC (History)
CC List:	1 user (show)

See Also:

Attachments
Add a check for CTS packets inside ForwardDown() (100.65 KB, patch) 2017-06-25 12:11 UTC, Varun Reddy	Details \| Diff
Add a check for CTS packets inside ForwardDown() (681 bytes, patch) 2017-06-25 12:18 UTC, Varun Reddy	Details \| Diff
Add a check for CTS packets inside ForwardDown() (664 bytes, patch) 2017-06-28 11:27 UTC, Varun Reddy	Details \| Diff
Show Obsolete (2) Add an attachment (proposed patch, testcase, etc.)

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Description Varun Reddy 2017-06-25 12:09:58 UTC

I'm unable to produce a script for this bug, since it does not pop up all the time. However, when I run the same script repeatedly for random TCP application start times (which in turn implies different scenarios), this bug appears. Nevertheless, I will try to post a script soon.

The problem arises in mac-low.cc when SendCtsAfterRts() is called (This does not happen all the time) and then ForwardDown() is called from within this function. Inside ForwardDown(), GetTid() is called, and since the Type ID for a CTS is not checked, it results in the fatal error (Line 163, qos-utils.cc)-      

NS_FATAL_ERROR ("Packet has no Traffic ID");

My suggestion would be to incorporate a check for CTS-type packets as well, inside ForwardDown().

Comment 1 Varun Reddy 2017-06-25 12:11:06 UTC

Created attachment 2875 [details]
Add a check for CTS packets inside ForwardDown()

Comment 2 Varun Reddy 2017-06-25 12:18:46 UTC

Created attachment 2876 [details]
Add a check for CTS packets inside ForwardDown()

Comment 3 sebastien.deronne 2017-06-27 16:24:36 UTC

Patch is OK, thanks.

Comment 4 Varun Reddy 2017-06-28 11:27:53 UTC

Created attachment 2884 [details]
Add a check for CTS packets inside ForwardDown()

Comment 5 sebastien.deronne 2017-07-02 09:45:20 UTC

Fixed in changeset 12944:12dacac685dc