Hi,
ekiga.net registrar uses kamailio 1.5.3 (yes, a bit old...) and for users who are not registered an empty NOTIFY body is returned when asked by a SUBSCRIBE. What does this mean from SIP standard point of view, and from kamailio point of view (are they identical?) I see in RFC3265/3.1.6.2: .... If the resource has no meaningful state at the time that the SUBSCRIBE message is processed, this NOTIFY message MAY contain an empty or neutral body but is difficult for me to interpret what it means.
Example: I ask the presence for a user xyz who registered and quit application long time ago:
SUBSCRIBE sip:xyz@ekiga.net SIP/2.0 CSeq: 1 SUBSCRIBE Via: SIP/2.0/UDP 82.238.108.175:5060;branch=z9hG4bKdabe824f-1a8e-e011-9efc-0024d693d8e8;rport User-Agent: Ekiga/3.3.1 From: sip:eugen.dedu@ekiga.net;tag=4888824f-1a8e-e011-9efc-0024d693d8e8 Call-ID: f602824f-1a8e-e011-9efc-0024d693d8e8@snoopy Supported: eventlist To: sip:xyz@ekiga.net Accept: application/pidf+xml Accept: multipart/related Accept: application/rlmi+xml Contact: sip:eugen.dedu@82.238.108.175:5060 Allow: INVITE,ACK,OPTIONS,BYE,CANCEL,SUBSCRIBE,NOTIFY,REFER,MESSAGE,INFO,PING,PRACK Expires: 300 Event: presence Content-Length: 0 Max-Forwards: 70
I receive the following answer:
NOTIFY sip:eugen.dedu@82.238.108.175:5060 SIP/2.0 CSeq: 1 NOTIFY Via: SIP/2.0/UDP 86.64.162.35;branch=z9hG4bK2a99.b8a72c47.0 User-Agent: Kamailio (1.5.3-notls (i386/linux)) From: sip:xyz@ekiga.net;tag=f85b0bd16aaafa8479586ac9f88b3198-10a0 Call-ID: f602824f-1a8e-e011-9efc-0024d693d8e8@snoopy To: sip:eugen.dedu@ekiga.net;tag=4888824f-1a8e-e011-9efc-0024d693d8e8 Contact: sip:86.64.162.35:5060 Subscription-State: active;expires=370 Event: presence Content-Length: 0 Max-Forwards: 70
To resume: What does SIP standard say about this NOTIFY with empty body? Does this mean that the user xyz is offline?
Or does this mean that user's status has not changed? In fact, the NOTIFY with empty body (as shown above) is the first one sent by kamailio, so there is no "previous" state of that user, hence "unchanged" status has no meaning.
Thank you,