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[Didier Barvaux <question263736@xxxxxxxxxxxxxxxxxxxxx>]

Question #263736 on rohc changed:
https://answers.launchpad.net/rohc/+question/263736

    Status: Open => Needs information

Didier Barvaux requested more information:
Hello,

> However, the app create a raw.txt file, where im able to see differents caracteristics:
> packet's number, size before and after compression... and the packet type. so i use this
> file to see the switch between each states.

Using the raw output of the rohc_stats tool is OK. There is an example for SO->FO transition at packet 3371:
  STAT  3370  1  U-mode   3  SO 8  RTP/UOR-2   1376  60 1327  11
  STAT  3371  1  U-mode   2  FO 8  RTP/UOR-2   1376  60 1327  11

It is not easy to see why from those lines alone. The library logs helped me a lot. Search for a debug trace that contains:
   timeouts for periodic refreshes: FO = 700 / 700


> I have a question concerning the ROHC feedback channel and the app stats.
>
> Did the app stats consider that this feedback channel is present? Did it use it ?

No, the rohc_stats tool doesn't handle feedback yet. It could be easily
added however. The  test/non_regression/test_non_regression.c tool is an
example of how a feedback channel may be added.


> I have a question (again). Indeed, when i use the app stats for an ipv4/tcp
> packets, im not able to see any switch after the CHANGE_IR_COUNT and
> CHANGE_FO_COUNT. Im only able to see the switch in the first nine
> packets. Is it normal?

If you use the IPv4/TCP capture included with the ROHC library, that's expected since the capture contains too few packets:
    $ capinfos ./test/non_regression/inputs/ipv4/tcp/source.pcap | grep ^Number
    Number of packets:   18 

I have just tested with a longer capture: it indeed doesn't work.
Periodic refreshes were not implemented in the TCP profile yet. I have
tried to add support for refreshes. It seems to work for the TCP stream
I captured. Please test the patch with yours and report me if it works
for you too.

Please find the patch there: http://pastebin.com/9MVeyVbZ

Regards,
Didier

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