[SR-Users] Robust header compression (RFC 3095) with Kamailio +rtpproxy

[Jeff Brower]

Alex-

> It is not supported by rtpproxy.  But you could run all that traffic
> inside a high-compression IP-in-IP UDP tunnel, though there would be
> an overhead penalty there too.

We've already extended rtpproxy for transcoding and encryption, we're thinking to continue with that approach for
header compression.

> Doesn't seem to me like this stuff really saves a lot of bandwidth,
> especially in a way that has meaningful network oversubscription
> returns.  You might be better off just using a low-bandwidth codec
> than worrying about all this.

Yes we're wondering also.  The main customer concern seems to be physically slow networks rather than
oversubscription.  I.e. geographical regions and/or equipment where voice channels are well under 50 kbps.  But you
make a good point, and we're trying to evaluate this carefully.

It does seem valuable if we can get down (and stay down) to a few bytes for all headers instead of 40.  Also it seems
a lot of work has gone in the area over the last few years.  For example, initial RFCs were sensitive to packet loss,
later revisions have improved this.

-Jeff

> On May 18, 2010, at 3:10 PM, Vikram Ragukumar
> <vragukumar at signalogic.com> wrote:
>
>> Hello,
>>
>> We are looking into bandwidth conservation by implementing RTP/UDP/
>> IP header compression.
>>
>> Has anybody implemented ROHC or another header compression scheme in
>> combination with kamailio + rtpproxy ? Could you please point us to
>> online documentation or other useful resources ?
>>
>> Thanks and Regards,
>> Vikram.