There is something called as answer-mode in SIP. The idea is to allow the UAC to request the UAS to auto-answer the call. At least in theory, this could be used to check the status of the phone without ringing it. This is obviously not an ideal replacement of OPTIONS. Also, this is a new spec so I'm not sure how many phone vendors support it yet:
http://www.ietf.org/internet-drafts/draft-ietf-sip-answermode-06.txt -- Raj ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Olivier Sent: Wednesday, January 09, 2008 1:47 AM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: Re: [asterisk-users] How to check if a SIP phone isforwardedwithout ringing it ? As using OPTIONS requests main benefit is to non-phone specific, what shall we do when most vendors do not comply with RFC ? 2008/1/9, Raj Jain <[EMAIL PROTECTED] >: This issue of phone vendors not supporting OPTIONS according to RFC 3261 often comes up on this list. Like Kevin Fleming said, an OPTIONS request is supposed to be responded in the same way as an INVITE. Almost all SIP phone vendors have construed OPTIONS as some kind of a keep-alive request, which is wrong. Can we ask the phone vendors to play by the book? -- Raj ________________________________ From: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> [mailto:[EMAIL PROTECTED] On Behalf Of Olivier Sent: Tuesday, January 08, 2008 7:50 AM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: Re: [asterisk-users] How to check if a SIP phone is forwardedwithout ringing it ? 2008/1/7, Kevin P. Fleming <[EMAIL PROTECTED]>: Olivier wrote: > Is there way for an Asterisk server to check if a sip phone is forwarded > without bothering phone's user ? No. > I was thinking of some Alert-Info option that would let the phone reply > with a 302 Moved Temporarily or 182 Queued message and not let the phone > ring or display anything on its screen. According to the SIP RFC, a SIP endpoint is supposed to respond to an OPTIONS message the same way that it would respond to an INVITE message with the identical destination, but I've never seen a phone respond to an OPTIONS message with anything but '200 OK', even when a redirect (forward) is in place. So, the alternative option is to play with html and use phone embedded html server to get this redirection data. Cheers -- Kevin P. Fleming Director of Software Technologies Digium, Inc. - "The Genuine Asterisk Experience" (TM) _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
