[asterisk-users] Sending INVITE to an unavailable phone - Bug?

[Joshua Colp]

----- Original Message -----
From: Douglas Garstang
[mailto:dgarstang at oneeighty.com]
To: Asterisk Users Mailing List -
Non-Commercial Discussion [mailto:asterisk-users at lists.digium.com]
Sent:
Mon, 14 Aug 2006 19:28:11 -0300
Subject: [asterisk-users] Sending INVITE to
an unavailable phone - Bug?


> I thought I'd bounce this around here before I opened a bug.
>  
> Phone A makes a call to phone B. Phone B is still registered, but is
> physically turned off.
>  
> Asterisk takes the INVITE message from phone A.
>  
> Now,
>  
> 1) It sends RINGING back to phone A before it has even sent an INVITE to
> phone B. Why does it do that? How does it know phone B is available? If
> phone B is not available, it should never send RINGING back to phone A.

What is your Dial line like? or what is the scenario in question?

> 2) It sends the INVITE to phone B. It then re-transmits the INVITE at least
> 3 times to phone B, all the while sending RINGING back to phone A. It just
> ocurred to me that Asterisk is using UDP for it's SIP messaging. This would
> explain why it doesn't know that phone B is not available. If it was using
> TCP, it would receive an instant connection failure, and would be able to
> stop sending RINGING to phone B. 
>  
> So, now I am wondering if anything can be done about this, given we're using
> UDP?

If you use qualify it will keep tabs on the phone and know when it is unavailable.

> Doug.

Joshua Colp
Digium