Subject: Re: Clarification of Expires header in an Invite

From: John Hearty <[email-masked]>
Date: Thu, 22 Apr 1999 11:21 -0500 (CDT)

>That is the intended application. The UAS wouldn't continue alerting
>past the Expires time. However, the spec doesn't *mandate* that the
>called party not send a final response after the Expires time ends.
>Thus, its really up to the UAC to decide how long its going to wait
>around. Nothing prevents if from waiting more or less than this time.
>Expires is really more of a hint.

Thanks.  That is what I thought and they way I was intending to use it.
We don't even have to send it, but wanted to provide the hint, and
would send a BYE upon timeout in the UAC.

John Hearty
MCI Worldcom

Date: Thu, 22 Apr 1999 11:03 -0500 (CDT)
From: Jonathan Rosenberg <[email-masked]>
To: John Hearty <[email-masked]>
CC: [email-masked]
Subject: Re: Clarification of Expires header in an Invite

John Hearty wrote:
> 
>  I need clarification of the Expires header in the Invite method.
> The RFC gives examples that it can limit the validity of an invitation
> if a client wants to limit the duration of a search or a conference
> invitation.  I take this to mean only the time in which the client
> is waiting for a final response, not the duration of the session.

Yes. Session duration is indicated in SDP, if you want.

> Is this correct?  If this is the case, a clarified description would
> be appreciated explicitly stating the client is waiting for a _final
> response_.  One scenario I plan on using this for is to give the callee
> a clue how long the caller will ring the device before giving up and
> moving on to another address in a serial search.

That is the intended application. The UAS wouldn't continue alerting
past the Expires time. However, the spec doesn't *mandate* that the
called party not send a final response after the Expires time ends.
Thus, its really up to the UAC to decide how long its going to wait
around. Nothing prevents if from waiting more or less than this time.
Expires is really more of a hint.

-Jonathan R. 

-- 
Jonathan D. Rosenberg                       Lucent Technologies
Member of Technical Staff                   101 Crawfords Corner Rd.
High Speed Networks Research                Holmdel, NJ 07733
FAX:   (732) 834-5379                       Rm. 4C-526
EMAIL: [email-masked]
URL: http://www.cs.columbia.edu/~jdrosen