[Serusers] Re: [Sip-implementors] RE: [Serdev] Rmoving to-tags - sr-users

3 Apr 2004

Jason Penton wrote:
...

>>>>Yes - I have. BUT I was under the impression that the 180 RINGING 
>>>>response is not REQUIRED to have a to-tag i.e. to set up an
>>>early dialog.
>>>
>>>>Is this understanding correct?
>>>
>>>indeed, to-tags serve the purpose if establishing a dialog. 
>>>180 does not establish any, only 183 does. 
I disagree. The only difference between 180 and 183 is that 180 
signifies that the callee is being alerted. Either may establish a 
dialog, or not.

...
 >>So then to fix the problem I am having - I
could 
>theoretically remove 
>>the to-tags from all incoming 180 RINGING responses before 
>forwarding 
>>them to the UAC and my problem should be solved. 
You could also remove the call-id header too, but I wouldn't recommend 
it. The to-tag can validly be there. You can start playing games to work 
around bugs in devices you encounter, but that will be dangerous.

	Paul