[asterisk-dev] chan_datacard and RTCP

[Artem Makhutov]

Hello,

Olle E. Johansson schrieb:
>
> 17 jan 2010 kl. 17.29 skrev Artem Makhutov:
>
>> Hello,
>>
>> I am writing chan_datacard to be able to use Huawei UMTS datacards as a GSM gateway with Asterisk.
>>
>> Some users have complained that their calls are disconnected after exactly 30 seconds.
>>
>> After some investigation it came out that they were using X-Lite as their sofphone and that X-Lite is disconnecting calls after 30 seconds if it does not receive RTCP packages in that time.
>>
>> So the question is how can I get asterisk to send RTCP packets to X-Lite?
>>
>> Must I add something to chan_datacard to generate RTCP packets or should asterisk generate RTCP packets by its own?
>> I have no clue about RTCP. Can somebody give me some hints at what I should look at?
>
> Asterisk generates RTCP unless there's an p2p RTP bridge, which I guess won't happen if you place a call from a SIP channel to your own channel. Turn on "rtcp debug" in the CLI and you'll get detailed information about RTCP messaging.

There is no P2P RTP bridge. The call goes directly from X-Lite to 
asterisk and from there to the GSM Network.

> I have never heard anything about X-lite disconnecting because there's no RTCP reports, that's very odd.

In X-Lite under Options -> Advanced -> Network -> Call Inactivity you 
can select if X-Lite should disconnect the call if no RTCP data has been 
recived for a given time. By default this is enabled and set to 30 seconds.

> For a bit more information about RTCP, I suggest that you read my blog about an on-going project to enhance RTCP support in Asterisk:
> http://www.voip-forum.com/asterisk/2010-01/measuring-voice-quality-asterisk/

Thanks, I have read this.

I did some more tests with asterisk and captured the output of rtcp set 
debug on:

http://pastebin.com/m36464d3d (RTCP between X-Lite and chan_datacard)
http://pastebin.com/m3105d3f8 (RTCP between X-Lite and chan_sccp)

I have captured the RTCP debug between X-Lite and chan_datacard.

Then I dialed a Cisco 7970 phone connected by chan_sccp from X-Lite. The 
Cisco phone is configured not to use direct RTP. So all RTP traffic goes 
through asterisk.

As faar as I understand the debug, the asterisk is sending RTCP in both 
cases. The question is why is X-Lite disconnecting after 30 seconds with 
chan_datacard and why is it not disconnecting when calling the Cisco phone?

Thanks, Artem

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 6531 bytes
Desc: S/MIME Cryptographic Signature
Url : http://lists.digium.com/pipermail/asterisk-dev/attachments/20100117/79479b91/attachment.bin