Interesting problem. suppose you did not fork requests and made a regular call, when would a call missed be indicated? Would that be after expiration of the "Expires" field in INVITE indicating that the far end has timed out ringing? If a CANCEL was sent before a session was created, would you still get a missed call indication?
Suppose you were'nt quick enough to send the CANCEL and two agents returned a 200 OK and you had to send a BYE, would one of them get a missed call indication? Thinking aloud - since the INVITE is the one that is a "special" invite, your question makes sense, if you could tag the INVITE instead of banking on the CANCEL header (e.g. reason). Is there an Alert-info header you could use to signify some sort of a distinctive ring if its a group ring? Kedar On 4/12/06, 이성우 <[EMAIL PROTECTED]> wrote: > > Dear, > > I am implementing a Group Ring facility in a small-sized IP-PBX system > that uses > 3 user agents internally. I wonder how I can mark a group ring INVITE > message to > differentiate other normal INVITE message? This is for clearing 'missied > call' log > at all other user agents except for the one that actually received the > call. > > Current Scenario is as followings. > > 1. Each user agent in IP-PBX system is set to a group ring function. > 2. There comes a SIP INVITE message from outside to IP-PBX system. > 3. IP-PBX system forwards the INVITE message to each user agent that are > in the same ring group. > 3. Each 3 user agent makes a ring responding 180 message each. > 4. One user agent receives and send 200 OK back to the caller (IP-PBX > system). > 5. Now that IP-PBX knows it received an answer from a user agent, it sends > CANCEL to other user agents. > 6. Each of the 2 user agents process the CANCEL message leaving 'missed > call' log in its LCD window. > > > > Caller UA IP-PBX UA1 UA2 UA3 > | INV | | | | > |----------------->| INV | | | > | |--------------->| | | > | | INV | | | > | |----------------------->| | > | | INV | | | > | |------------------------------>| > | | 180 | | | > | |<---------------| | | > | | 180 | | | > | |<-----------------------| | > | | 180 | | | > | |<------------------------------| > | | 200 | | | > | |<---------------| | | > | | ACK | | | > | |--------------->| | | > | | CANCEL | | | > | |----------------------->| | > | | CANCEL | | | > | |------------------------------>| > > > My questions are > Q1. How can I let the user agents know that the incomming INVITE message > is group-call? > Q2. If I use a specific SIP Header in the INVITE message (from IP-PBX to > UAs) to carry > the group-call infomation, what header should I use and how? > Q3. Can I use the specific SIP Header in CANCEL message instead of INVITE > for the same purpose? > > Thanks in Advance. > > > > Lee, Sungwoo > > OfficeServ Development/VoIP > Telecommunication System Div. > Samsung Electronics Co., LTD. > > [EMAIL PROTECTED] > TEL: 82-31-279-4329 > FAX: 82-31-279-2296 > Mobile: 82-10-3015-4329 > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
