Subject: Re: [rohc] ROHC packet traces/CRC calculation example.

From: Alan Kennington <[email-masked]>
Date: Sun, 21 Sep 2003 01:06:35 +0930

On Fri, Sep 19, 2003 at 06:06:42PM -0400, Remi Pelland wrote:
> 
> Does anyone know if there are any records of packet traces taken
> during the interoperability tests?  I'm mostly interrested in the CRC
> calculation of compressed header since I would like to compare my
> algorithm against something that is known to work.
> 

Rémi,

I can't help directly with that question. But for the distant future, I
have a suggestion. If an RFC was defined for "ROHC over UDP" then we
could all test our implementations over the Internet.  Of course, this
would not be a 100% test of all aspects, but it would certainly test 99%
of the protocol syntax and semantics.

This could be implemented quite simply on unix systems by modifying an
ROHC/PPP implementation so that the packets are fed to a user-space
process via a character-device, and each packet could then be sent to a
remote host in a UDP packet.

Maybe then someone could make available a standard reference ROHC over
UDP implementation for everyone to test their implementations against.
This would be much less costly than interop meetings - and even us poor
people could participate.

Cheers,
Alan Kennington.

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From: Remi Pelland <[email-masked]>
Date: Fri, 19 Sep 2003 18:06:42 -0400

Hi,

Does anyone know if there are any records of packet traces taken during the
interoperability tests?  I'm mostly interrested in the CRC calculation of
compressed header since I would like to compare my algorithm against
something that is known to work.

Perhaps this could be an interresting addition to the Implementer's Guide?
There could be a few IPv4 and IPv6 headers and for each of them the
associated CRC-3/CRC-7 for the case where the packet is sent compressed, and
the associated CRC-8 values for cases where the packet is sent via IR and
IR-DYN.  I know the i.g. does provide a CRC algorithm already, but examples
with actual packets would also validate the STATIC and DYNAMIC
classifications that is defined for compressed headers.  Any kind of
tangible example would be helpful I believe.

In the mean time, if you have that information available or if you have your
own traces that you're willing to share, I would greatly appreciate it.

Thanks in advance,
Remi.