[asterisk-users] How to check if a SIP phone isforwardedwithout ringing it ?

[Raj Jain]

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: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] 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 <rj2807 at gmail.com >: 

		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: asterisk-users-bounces at lists.digium.com
<mailto:asterisk-users-bounces at lists.digium.com> 
		[mailto:asterisk-users-bounces at lists.digium.com] 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 <kpfleming at digium.com>: 
		
		                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) 
		
		
		
		
		
		
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