Re: [Sip] Impossible to use real persistent connection with sip

[Sean Olson <seancolson@yahoo.com>]

I'm looking forward to reading the draft.
I think this is a common problem that deserves
greater scrutiny. I don't think there is any 
lack of potential solutions. I would like to see
some clean (informational) recommendations on
how this should be done. In addition to connection
persistence, I think connection re-use is an
interesting problem that could potentially be 
solved with a common design. This is similar
to recommendations on how best to use SCTP
in a SIP environment.

Regards,
Sean Olson
Microsoft


--- "Vijay K. Gurbani" <vkg@lucent.com> wrote:
> Christian Jansson wrote:
> >>Section 18 of rfc3261 correctly instructs
> implementors to 
> >>close connections after a certain time (64*T1).  
> > 
> > No, it does not. Section 18 does not say when to
> close sockets, 
> 
> That's your interpretation.  When I read the
> following sentence from
> section 18:
> 
>     "It is RECOMMENDED that connections be kept open
> for some
>     implementation-defined duration..."
> 
> It implies to me that after the duration has passed,
> the entity is
> free to close the socket.
> 
> > but
> > rather that you should not close the socket to
> soon. So if you feel like
> > it, you could leave the connection open forever.
> 
> I am afraid I don't read it that way; i.e. leave the
> connection open
> forever.
> 
> > Not needed. Close the socket when you have to, and
> probably it will be
> > more effective to keep it open for a while in case
> you need it again (as
> > Cullen Jennings wrote).
> 
> Exactly how long is the question.  For some peering
> arrangements between
> service providers and for UACs always using a
> default outbound proxy,
> does it make sense to leave TCP/TLS sockets open for
> a longer time than
> a transaction.  That is the crux of the problem.
> 
> Cullen Jennings writes:
> > Hmm - I did not read 3261 quite that way.
> > 
> > I thought it was more along the lines of what you
> want to get too where 
> > it is up to the proxy and UA to make intelligent
> decision about when to 
> > close a connection. I think it would be good to
> provide some information 
> > level advice about schemes UA and Proxies might
> want to use to do a good 
> > job of this.
> 
> Right; or schemes between proxies.
> 
> > If this required more information to be passed
> between them to do a
> > good job of it that would be interesting but
> without seeing the 
> > scheme it is hard to see that they need any more
> information than 
> > they have today.
> 
> Fair enough.  Folks on the CC list (except
> sip@ietf.org :-)) are working
> on an I-D and it'll be available as soon as they are
> done.
> 
> Thanks,
> 
> - vijay
> -- 
> Vijay K. Gurbani 
> vkg@{lucent.com,research.bell-labs.com,acm.org}
> Wireless Networks Group/Internet Software and
> Services
> Lucent Technologies/Bell Labs Innovations, 2000
> Lucent Lane, Rm 6G-440
> Naperville, Illinois 60566     Voice: +1 630 224
> 0216
> 
> _______________________________________________
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> This list is for NEW development of the core SIP
> Protocol
> Use sip-implementors@cs.columbia.edu for questions
> on current sip
> Use sipping@ietf.org for new developments on the
> application of sip


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