Bug 141 – udp tx buffer is not fixed size

Bug 141 - udp tx buffer is not fixed size


Summary:	udp tx buffer is not fixed size

Status:	RESOLVED WONTFIX

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

Importance:	P3 normal
Assigned To:	Mathieu Lacage

URL:
Keywords:

Depends on:
Blocks:
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Reported:	2008-02-15 12:32 UTC by Mathieu Lacage
Modified:	2013-08-06 14:07 UTC (History)
CC List:	3 users (show)

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Description Mathieu Lacage 2008-02-15 12:32:21 UTC

We need to make it a fixed size and handle correctly sending udp packets which do not fit in the tx buffer.

First, we need to figure out what we should do in the latter case and what happens in linux udp sockets when the tx buffer is full: are packets dropped ?

Comment 1 Gustavo J. A. M. Carneiro 2008-02-16 09:31:17 UTC

I don't think UDP sockets have transmit buffer in Linux. See http://book.chinaunix.net/special/ebook/oreilly/Understanding_Linux_Network_Internals/0596002556/understandlni-CHP-21-SECT-1.html#IDX-CHP-21-2574

    """udp_sendmsg first calls ip_append_data, and then forces the immediate transmission of the data with udp_push_pending_frames only if corkreq is false"""

But the "cork" option is an advanced udp socket option, disabled by default.  By default UDP has no buffering; there's only a transmit queue in the netdevice itself.

Comment 2 Mathieu Lacage 2008-06-06 14:54:53 UTC

until we implement CORKED udp sockets or the MSG_MORE socket flag for udp socket options, we do not need to worry about this issue I think. I would like to decrease the priority of this bug.

Comment 3 Tom Henderson 2008-06-06 17:51:09 UTC

OK, bumping to p3

Comment 4 Mathieu Lacage 2009-11-23 08:40:44 UTC

Maybe we should just mark this bug as WONTFIX. tom ?

Comment 5 Tom Henderson 2009-11-24 00:05:24 UTC

(In reply to comment #4)
> Maybe we should just mark this bug as WONTFIX. tom ?

I have no plans to work on this enhancement.  WONTFIX ok for me.

Comment 6 Josh Pelkey 2010-02-20 12:55:24 UTC

Please mark WONTFIX if this is still the case.

Comment 7 Tommaso Pecorella 2013-08-05 17:41:39 UTC

Bump.

3 years have passed and this bug is still "new". Shall we mark it as WONTFIX perhaps?
I hate open (and rotting) bugs, they're... not good.