Subject: RE: [Sip] PING/PONG

From: "Steve Langstaff" <[email-masked]>
Date: Wed, 10 Nov 2004 09:39:07 -0000

(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. 

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