rohc team mailing list archive

[Didier Barvaux <didier@xxxxxxxxxxx>]

Faraz,

Please keep the discussion on the mailing list. My answers below.

On Tue, 2 Apr 2013 16:17:59 -0700 (PDT),
faraz iqbal <faraz4557@xxxxxxxxx> wrote:
>
> Hi
> > > b/ Mode is O-mode, with out periodic update but compressor send IR
> > > header for a queue time out (beyond 30 sec) at compressor end IR
> > > with out recovery request from de-compressor.
> >
> > The library does not have any timer. There is no mechanism for queue
> > timeout either. This is a task for the applications using the
> > library, not the library itself.
> >
> > With what program do you use the ROHC library? Your problem might
> > come from that program.
> 
> I am using MGEN, i have also checked with ping test.

Are you talking about http://cs.itd.nrl.navy.mil/work/mgen/index.php ?
If yes, you misunderstood my question. I rephrase it: the ROHC library
is a library, not an application or program, so you cannot use the ROHC
library alone; what program based on the ROHC library are you using?
Said otherwise, what command line do you run to "start the ROHC
library"?


> I have notice
> the same behavior which is IR header send only at the starting point
> only then compressor goes to FO & SO state until it is not struck by
> decompressor for error recovery.

OK.

> Furthermore, the RFC 3095 also
> described that there are no periodic updates in O-mode.

Yes, the ROHC library is not conform to RFC 3095 on that part.


> I have attached my queue hierarchy which is build in linux based
> router.

OK. I understand now, the queue you talked about was the queue of TC
qdiscs...


> Secondly the screen shot of wireshark trace file where
> compressor repeat the IR header after a packet loss.

Are the Ethernet frames with Ethertype 0x8888 and 0x8889 the IR packets
you are talking about?


> If there is no
> time out in library then the compressor might act it as link failure
> and then reconnect the link with decompressor by send full header.

The ROHC compressor is not able to detect "link failure" itself except
if it receives several negative feedbacks. However the program using
the ROHC compressor may destroy then re-create the compressor or reset
its state. What application are you using?

Regards,
Didier

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