Hi Ranga
Since the stateful proxy maintains state of every transacion,
retransmission is one function that it could perform.. It may not be used if
UAC takes care of that.
Also if proxy is stateful, then UAC will perform retransmissions till proxy
(next hop) and beyond that proxy will take care.
Regards
Ranjit
----- Original Message -----
From: M. Ranganathan <[EMAIL PROTECTED]>
To: Ranjit Avasarala <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Thursday, June 14, 2001 1:09 PM
Subject: RE: [Sip-implementors] Stateful vs Stateless vs something in
between?
Hi Ranjit:
As I stated in my first message in this thread,
( Clearly, there are instances where proxies need to be
> stateful to support certain kinds of funcitonality whereas
> for things such
> as re-transmission, I see these as being performance
> enhancements in the
> proxy. )
Here I am specifically referring to re-transmission as a requirement for
stateful proxies and I just wanted to know why this is a requirement.
Thanks
Regards,
Ranga.
--
M. Ranganathan
National Institute of Standards and Technology
Advanced Networking Technologies Division
100 Bureau Drive, Stop 8920,
Gaithersburg, MD 20899, U.S.A.
Tel:(301)975-3664 Fax:(301)590-0932
Advanced Networking Technologies For the People!
-----Original Message-----
From: Ranjit Avasarala [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 14, 2001 12:51 PM
To: M. Ranganathan
Cc: [EMAIL PROTECTED]
Subject: Re: [Sip-implementors] Stateful vs Stateless vs something in
between?
Hi Ranga
you are limiting the functionality of stateful proxy to just
retransmissions.Stateful proxy can do many other things,
Like by maintaining the states you can generate reports, billing info, etc.
So all these functionalities can be implemented using a
stateful proxy ( which u cannot in a stateless proxy).
Regards
Ranjit
Mascon Communication Technologies
http://www.masconit.com
----- Original Message -----
From: M. Ranganathan <[EMAIL PROTECTED]>
To: Ranjit Avasarala <[EMAIL PROTECTED]>
Sent: Thursday, June 14, 2001 11:29 AM
Subject: RE: [Sip-implementors] Stateful vs Stateless vs something in
between?
Ranjit:
The UAC does not know if it is talking to a stateful or stateless proxy so
it must retransmit anyway so what is the point (other than efficiency) of
expecting the stateful proxy to retransmit? If there is a necessary reason
(affecting correctness rather than efficiency), I am not clear about it or I
have mis-understood something.
Ranga.
--
M. Ranganathan
National Institute of Standards and Technology
Advanced Networking Technologies Division
100 Bureau Drive, Stop 8920,
Gaithersburg, MD 20899, U.S.A.
Tel:(301)975-3664 Fax:(301)590-0932
Advanced Networking Technologies For the People!
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Ranjit
Avasarala
Sent: Thursday, June 14, 2001 12:32 PM
To: M. Ranganathan; [EMAIL PROTECTED]
Subject: Re: [Sip-implementors] Stateful vs Stateless vs something in
between?
Hi
Ranganathan,
what I understand from stateful and stateles proxies is :
If you r using a stateful proxy then the proxy will take care of
retransmissions. But if UAC is taking care of retransmissions then
they will be w.r.t the proxy.
correct me if I am wrong.
Regards
Ranjit
----- Original Message -----
From: M. Ranganathan <[EMAIL PROTECTED]>
To: Jonathan Rosenberg <[EMAIL PROTECTED]>;
<[EMAIL PROTECTED]>
Sent: Thursday, June 14, 2001 10:58 AM
Subject: RE: [Sip-implementors] Stateful vs Stateless vs something in
between?
Jonathan:
Thanks for your answer. Perhaps I have this figured out wrong but I am still
confused:
For end-to-end reliability, the UAC does not know about whether it is
talking to a stateful or stateless proxy therefore it must retransmit
requests so why does a stateful proxy need to worry about re-transmissions
at all (other than for reasons of efficient operation and improved
performance)?
Regards
Ranga.
--
M. Ranganathan
National Institute of Standards and Technology
Advanced Networking Technologies Division
100 Bureau Drive, Stop 8920,
Gaithersburg, MD 20899, U.S.A.
Tel:(301)975-3664 Fax:(301)590-0932
Advanced Networking Technologies For the People!
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Jonathan
Rosenberg
Sent: Thursday, June 14, 2001 3:21 AM
To: 'M. Ranganathan'; [EMAIL PROTECTED]
Subject: RE: [Sip-implementors] Stateful vs Stateless vs something in
between?
> -----Original Message-----
> From: M. Ranganathan [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, June 13, 2001 5:14 PM
> To: [EMAIL PROTECTED]
> Subject: [Sip-implementors] Stateful vs Stateless vs something in
> between?
>
>
> Hello!
>
> There is a distinction made in the RFC between stateful and stateless
> proxies. For example, stateful proxies are supposed to keep
> transaction
> state and are responsible for re-transmission of requests.
>
> Given that a user agent is oblivious to whether it is talking
> to a stateful
> or stateless proxy at least some of these functions (such as
> re-transmission
> of requests) have to be supported by the user agent anyway leading to
> redundancy. ( Clearly, there are instances where proxies need to be
> stateful to support certain kinds of funcitonality whereas
> for things such
> as re-transmission, I see these as being performance
> enhancements in the
> proxy. )
>
> Is it required that proxies choose one mode versus the other
> (i.e. stateful
> versus Stateless) or can they adopt an intermediate strategy?
I'm not sure what you mean by an "intermediate strategy". A proxy can choose
to be stateful or stateless for each transaction on a case by case basis.
However, if you want to implement some kind of new level of state (for
example, where you retransmit the request in a proxy twice, and then become
stateless), you really can't do that. In most cases, it will effect end to
end reliability. Correct operation is guaranteed by compliance to the
defined FSMs. If you deviate from them, bets are off.
-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PHONE: (973) 952-5000
http://www.dynamicsoft.com
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