Subject: SIP session liveliness

From: "Paul Defrain" <[email-masked]>
Date: Thu, 28 Oct 1999 00:09:52 -0500

All,

While we're on the topic of SIP INFO message use, it seems reasonable to
assume that we will need to develop a way to ascertain whether or not a SIP
session is active. Once a SIP session is established there remains no
required "connection" that physically ties the involved parties together. If
one party leaves the session and cannot (or does not) contact the other then
network resources could be lost (depending on the nature of the application
involved in the session). We have identified the need to occasionally "ping"
a SIP call based on its call-id (the only persistent piece of data that
ultimately identifies an established application session). We foresee the
use of the SIP INFO request against the affected call-id along with its 200
response (or other final or non-response in case of error) as an indication
of session liveliness. We will use this technique protect (reclaim) limited
network resources involved in some sessions established using SIP as the
messenger.

Has this type of messaging between established sessions been addressed in
this or some other forum? Has anyone implemented this sort of functionality
in their application(s).

__________________________
Paul D. DeFrain
IP Services SIP Feature Development
ESN 444.7570 (972) 684.7570
[email-masked]

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From: "Donovan, Steven R." <[email-masked]>
Date: Thu, 28 Oct 1999 15:30:53 +0000

Paul,
 
Please see the following draft:
http://www.ietf.org/internet-drafts/draft-ietf-sip-session-timer-00.txt
<http://www.ietf.org/internet-drafts/draft-ietf-sip-session-timer-00.txt> 

This is another method for achieving your goal.  It is more of a keep-alive
mechanism than the ping method you propose.

Regards,

Steve

-----Original Message-----
From: Paul Defrain [mailto:[email-masked]]
Sent: Thursday, October 28, 1999 12:10 AM
To: [email-masked]'
Subject: SIP session liveliness

All,