Subject: [Sip] Event Based Heart Beat in SIP

From: "Samir Srivastava" <[email-masked]>
Date: Tue, 7 Oct 2003 17:12:44 -0700

Hi,

The current standard provides OPTIONS to find the liveness of remote SIP
endpoint.
If remote SIP server is not able to response back for the OPTIONS for a
long time,
it results in bunch of OPTIONS requests in the network. There is no
standard
event defined which tells the availability of remote SIP endpoint. 

Consider SIP endpoints A (local) wants to find out the availabilty of
B(remote).
A subsribes event "READY_TO_PROCESS"  to B, when B is ready to process 
SIP reqs.  The subscribers of event needs to stored persistenly. As soon
as SIP 
server is ready for signal processing, it will send the NOTIFY
indicating its
availability. This eliminates the OPTIONS REQs when remote endpoint is
not
available for checking liveness ? 

Other events can be also added, like update the availability when there
is
no SIP traffic.

Whether checking liveness based on the events was considered earlier ?

Thx
Samir

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From: Srikanth Sundaragopalan <[email-masked]>
Date: Tue, 7 Oct 2003 20:48:18 -0400 (EDT)

Refer draft-ietf-simple-presence-10.txt,which talks about essentially
what you have described.

If you want liveliness within a dialog,meaning you want to know whether
the remote end is still active,you might want to look into session timer
features.

regds
Srikanth Sundaragopalan
Graduate Student
College of Computing
Georgia Tech