> -----Original Message-----
> From: Arunachalam Venkatraman [mailto:[EMAIL PROTECTED]]
> Sent: Friday, March 30, 2001 10:53 AM
> To: Jonathan Rosenberg; [EMAIL PROTECTED]
> Subject: RE: [Sip-implementors] Retransmissions in Proxy
>
>
> Jonathan
> I am seeking to clarify that in the statement from your reply
> When a provisional arrives, the interval goes to 4s if
> it is not already at 4s.
> the number of retransmissions for non-INVITE requests is unaffected
> (i.e.remains at 10).
>
> Also, is this mentioned anywhere in the rfc or bis?
Yes, of course. These rules are in plain sight in bis -02, right at the
front of the sections which discuss reliability.
For non-INVITE, section 10.2.1:
A SIP client using an unreliable transport protocol such as UDP SHOULD
retransmit requests other than
INVITE or ACK with an exponential backoff, starting at a T1 second interval,
doubling the interval for
each packet, and capping off at a T2 second interval. This means that after
the first packet is sent, the
second is sent T1 seconds later, the next 2 T1 seconds after that, the
next 4 T1 seconds after that, and
so on, until the interval reaches T2 . Subsequent retransmissions are spaced
by T2 seconds. If the client
receives a provisional response, it continues to retransmit the request, but
with an interval of T2 seconds.
Retransmissions cease when the client has sent a total of eleven packets, or
receives a definitive response.
For INVITE, section 10.3.1:
A SIP client using an unreliable transport protocol SHOULD retransmit a SIP
INVITE request with an interval
that starts at T1 seconds, and doubles after each packet transmission. The
client ceases retransmissions if
it receives a provisional or definitive response, or once it has sent a
total of seven request packets.
-Jonathan R.
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]] On Behalf Of Jonathan
> Rosenberg
> Sent: Thursday, March 29, 2001 12:27 AM
> To: 'Deepak Mohan'; [EMAIL PROTECTED]
> Subject: RE: [Sip-implementors] Retransmissions in Proxy
>
>
>
>
>
> > -----Original Message-----
> > From: Deepak Mohan [mailto:[EMAIL PROTECTED]]
> > Sent: Tuesday, March 27, 2001 11:35 PM
> > To: [EMAIL PROTECTED]
> > Subject: [Sip-implementors] Retransmissions in Proxy
> >
> >
> > Section 12.3.4 of bis-02 states that responses from UAS are
> > cached and retransmitted to a UAC on a stateful proxy.
> > Does a proxy retransmit cached *requests* to UASs on
> > non-arrival of responses?
>
> The behavior for transmissions of requests at a stateful
> proxy is the same
> as a UAC. For invite, they are retransmitted with an
> increasing period until
> a provisional or final response, at which time they stop. For
> non-INVITE,
> they are retransmitted with an increasing period until 4s, and then
> retransmitted at 4s. When a provisional arrives, the interval
> goes to 4s if
> it is not already at 4s. Request retransmissions stop when a
> final response
> arrives.
>
>
> > Or do the retransmissions originate
> > at the UAC?
>
> A stateful proxy re-originates the request.
>
>
> > I beleive that the proxy will retransmit requests if forked,
> > but otherwise?
>
> A forking proxy must be stateful, but a non-forking proxy can also be
> stateful.
>
> -Jonathan R.
> ---
> Jonathan D. Rosenberg 72 Eagle Rock Ave.
> Chief Scientist First Floor
> dynamicsoft East Hanover, NJ 07936
> [EMAIL PROTECTED] FAX: (973) 952-5050
> http://www.cs.columbia.edu/~jdrosen PHONE: (973) 952-5000
> http://www.dynamicsoft.com
> _______________________________________________
> Sip-implementors mailing list
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---
Jonathan D. Rosenberg 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.cs.columbia.edu/~jdrosen PHONE: (973) 952-5000
http://www.dynamicsoft.com
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