Subject: [Sip] Open Issue #126: ACK never received for 2xx to re-INVITE

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 5 Dec 2001 21:37:34 -0500

Issue:

What to do if you never get an ACK for a 2xx you sent to a re-INVITE?
Currently, it says to re-INVITE to restablish state. However, thats going to
get complicated. An alternative is to just BYE the call.

Discussion points:

If a 2xx response to an initial INVITE never generates an ACK, you are
supposed to BYE. I think it makes sense, in the interests of uniformity of
INVITE/re-INVITE, and KISS, to simply BYE in odd cases like this.

Proposal:

Send a BYE

---
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From: "Brett Tate" <[email-masked]>
Date: Thu, 6 Dec 2001 16:11:47 -0500

> INVITE/re-INVITE, and KISS, to simply BYE in odd cases like this.

How about "MUST send reINVITE or BYE"?

This wording allows the UAS to either
release or recover the call.  It also 
discourages devices from dropping the 
call without sending BYE as a means to
avoid sending BYE 11 times.

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From: Gonzalo Camarillo <[email-masked]>
Date: Fri, 07 Dec 2001 01:17:04 +0200

Hi,

> INVITE/re-INVITE, and KISS, to simply BYE in odd cases like this.

I go all the way for uniformity, but I do not think that we need
uniformity between INVITE and re-INVITE. We rather need it between
requests sent within a dialog.

Section 12.2.1.2 says that if a request within a dialog is responded
with 481 or 408 the dialog SHOULD be terminated.

Since not receiving an ACK is effectively the same as a 408 response I
agree with your proposal: If no ACK is received the UAS SHOULD send a
BYE.

Regards,

Gonzalo

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