[Asterisk-Dev] IP-ID in RTP UDP packets

[Olle E. Johansson]

Aj wrote:
>>>- force linux to send the right IP-ID?
>>
>>What for?
> 
> 
> well, right right behaviour of all the fields in the RTP/UDP/IP
> packets are needed for header compression schemes. And without it the
> header compression used for VoIP calls will face some problems.
> 
> I was wondering if anybody using asterisk has faced issues with this regard...
> 
> 
>>>- or to set the DF bit to 0 in an attempt to make the IP stack to put in
>>>the right IP-ID?
>>
>>Why?
>>
>>Ask on loonix-kernel instead, this is not an asterisk question.
> 
> 
>>From some investigation in about the linux kernel, looks like the
> current behaviour is specific to linux implementation. There are long
> email threads which discusses problems with header compression with
> the current linux implementation. If interested you can read about it
> at
> 
> http://www.linuxsa.org.au/pipermail/linuxsa/2003-May/055033.html
> 
> Given that the asterisk server will be on linux and with the current
> growth in its popularity, I expect this to be used along with header
> compression and taking care of this problem by asterisk(if possible)
> will certainly give it more reasons to be the choice of IP-PBX.
> 
> I want to let the asterisk developers know of this so that it can be
> taken care of. I had to put in my own hacks to make the IP-ID behave
> correctly so that the header compression of the RTP/UDP/IP stream
> coming from asterisk(on linux) has no sideeffects.
> 
If you have hacks, send in a disclaimer and add them to the bug tracker
so that we can understand and use your code or are able to use your code
as a base for a patch.

Thank you for contributing to the community with your knowledge!

/Olle