Subject: RE: [Sip] PING/PONG

From: "Chris Boulton" <[email-masked]>
Date: Wed, 10 Nov 2004 13:45:18 -0000

Yes - this has nothing to do with dialog's.  The requirement is to keep
bindings alive regardless.

Chris.

-----Original Message-----
From: Christian Stredicke [mailto:[email-masked]] 
Sent: 10 November 2004 10:36
To: Steve Langstaff; Chris Boulton; Christer Holmberg (JO/LMF);
[email-masked]
Cc: [email-masked]
Subject: RE: [Sip] PING/PONG

True. For that purpose, use e.g. INFO messages with no body. These
messages keep the dialog "alive". 

However, the goal of the PING/PONG keep-alive messages is to keep the
NAT-binding alive. So that you are able to receive the first INVITE!

CS

  _____  

	From: [email-masked] [mailto:[email-masked]] On
Behalf Of Steve Langstaff
	Sent: Wednesday, November 10, 2004 5:16 AM
	To: Christian Stredicke; Chris Boulton; Christer Holmberg
(JO/LMF); [email-masked]
	Cc: [email-masked]
	Subject: RE: [Sip] PING/PONG

	(CS) OPTIONS has the problem that it is relatively expensive
(size and CPU) and might result in responses that exceed the UDP
fragmentation limit (there are many DSL routers that treat UDP
fragmentation as security problem including the one that I have at
home). Therefore I think it would not hurt to have a specific message
that is designed only for the keep-alive job.

	...but if you want your keep alive message to be routed over the
same path and transports as your original INVITE (and hence keep them
alive), don't you need most of the "expensive" content of (say) the
OPTIONS message - e.g. the vias.

	-- 
	Steve Langstaff. 

This email and any attached files are confidential and copyright protected.  If you are not the addressee, any dissemination, distribution or copying of this communication is strictly prohibited.  Unless otherwise expressly agreed in writing, nothing stated in this communication shall be legally binding.
_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip