[SIP Beyond VoIP] couple of sylkserver questions

Saúl Ibarra Corretgé saul at ag-projects.com
Wed Nov 14 09:47:17 CET 2012


Hi Juha,

On Nov 14, 2012, at 9:41 AM, Juha Heinanen wrote:

> Saúl Ibarra Corretgé writes:
> 
>> The participants list is fetched with a subscription to the
>> 'conference' event. SIP SIMPLE (the SDK) will always subscribe to such
>> event if the remote Contact header contains ';isfocus'. Now
>> sip-session doesn't print participants, but it wouldn't be hard at all
>> to do so, since it already subscribes to such event. Also, what
>> RFC4353 refers to as 'fetch' is just sending a SUBSCRIBE with expires
>> 0, in order to trigger a NOTIFY with the participants update, but in
>> our case we already have such list though is not printed anywhere.
> 
> saul,
> 
> i gave subscribe with expires=0 a try and got 423 Interval Too Brief
> back:
> 
> T 2012/11/14 10:35:54.412755 127.0.0.1:58868 -> 127.0.0.1:5092 [AP]
> SUBSCRIBE sip:+35892345671*3655*8681 at cf.test.fi SIP/2.0.
> Via: SIP/2.0/TCP 192.98.102.10;branch=z9hG4bK02c3.1f2e4bd2000000000000000000000000.0.
> To: <sip:+35892345671*3655*8681 at cf.test.fi>.
> From: <sip:jh at test.fi>;tag=50a357ea62873.
> CSeq: 1 SUBSCRIBE.
> Call-ID: 50a357ea62873.
> Content-Length: 0.
> User-Agent: OpenXg SIP Proxy  (3.4.0-dev4 (i386/linux)).
> Contact: <sip:click2sub at 192.98.102.10:5060>.
> Event: conference.
> Expires: 0.
> Accept: application/conference-info+xml.
> Allow-Events: conference.
> .
> 
> T 2012/11/14 10:35:54.413415 127.0.0.1:5092 -> 127.0.0.1:58868 [AP]
> SIP/2.0 423 Interval Too Brief.
> Via: SIP/2.0/TCP 192.98.102.10;received=127.0.0.1;branch=z9hG4bK02c3.1f2e4bd2000000000000000000000000.0.
> Call-ID: 50a357ea62873.
> From: <sip:jh at test.fi>;tag=50a357ea62873.
> To: <sip:+35892345671*3655*8681 at cf.test.fi>.
> CSeq: 1 SUBSCRIBE.
> Server: SylkServer-2.2.1.
> Content-Length:  0.
> 
> i think that according to rfcs, subscribe with expires value 0 should 
> result in a 200 response as well as an immediate single NOTIFY 
> indicating that the subscription has been terminated.
> 
> is this a bug in pjsip stack?
> 

We are handling handling the SUBSCRIBE requests ourselves in the SDK before interfacing with PJSIP, so it's our bug most likely. Thanks for the report!

--
Saúl Ibarra Corretgé
AG Projects





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