Subject: RE: [Sipping] Details on SBC

From: "Christian Stredicke" <[email-masked]>
Date: Wed, 11 May 2005 12:17:53 +0200

Hi Samir, also take a look at http://snom.com/download/natf_211.pdf.
There is some explanations of what we are going. At least.
 
We did ICE ("local media path optimization") in the beginning, but
because of the latest changes in the draft we decided not to do any more
changes until this is in a stable state. We don't like moving targets.
And practically it does not seem to play the role that we thought it
would do. Today I would say it is more important to locate the nearest
SBC for the UA (for a globally operating ITSP).
 
CS

________________________________

	From: [email-masked] [mailto:[email-masked]]
On Behalf Of Samir Chatterjee
	Sent: Saturday, May 07, 2005 12:46 AM
	To: [email-masked]
	Subject: [Sipping] Details on SBC

	Hi:

	We are looking for some details on SBC and how they work in
terms of call flows etc. Any pointers?

	Also, does someone know of an actual implementation of ICE for
NAT/FW traversal. It could be either commercial or open-source.
Something that we could test for performance. Any help would be
appreciated.

	Dr. Samir Chatterjee

	Founding Director, NCL http://ncl.cgu.edu

	School of Information Science

	Claremont Graduate University

	130 East 9th Street

	Claremont, CA 91711

	(P) 909-607-4651

	(F) 909-621-8564

	http://fac.cgu.edu/~chatters

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: [email-masked]
Date: Wed, 11 May 2005 10:06:40 -0500

Samir,

SIP is specified in a collection of standards documents and the SBC is not
part of SIP.

The requirements for NAT are quite stable and formulated in

http://www.ietf.org/internet-drafts/draft-ietf-behave-nat-udp-01.txt 

The NAT traversal scenarios with detailed messages are given in

http://www.ietf.org/internet-drafts/draft-ietf-sipping-nat-scenarios-02.txt 

This should give you enough to implement ICE and avoid SBC products for all
the reasons discussed on this list, if one can actually specify what an SBC
is. 100's of attendees at the IETF BOFs on SBC could not. See the report in
the attached. No doubt there are many SBC vendors who will assert to meet
your needs, so you can make the decision for yourself if you want to go with
the SIP standard or use SBC.

See the attached for more details.

Thanks, Henry

Henry Sinnreich
pulver.com
115 Broadhollow Rd
Suite 225
Melville, NY 11747
USA

  _____  

From: Christian Stredicke [mailto:[email-masked]] 
Sent: Wednesday, May 11, 2005 5:18 AM
To: Samir Chatterjee
Cc: [email-masked]
Subject: RE: [Sipping] Details on SBC

Hi Samir, also take a look at http://snom.com/download/natf_211.pdf. There
is some explanations of what we are going. At least.

We did ICE ("local media path optimization") in the beginning, but because
of the latest changes in the draft we decided not to do any more changes
until this is in a stable state. We don't like moving targets. And
practically it does not seem to play the role that we thought it would do.
Today I would say it is more important to locate the nearest SBC for the UA
(for a globally operating ITSP).

CS

  _____  

From: [email-masked] [mailto:[email-masked]] On Behalf
Of Samir Chatterjee
Sent: Saturday, May 07, 2005 12:46 AM
To: [email-masked]
Subject: [Sipping] Details on SBC

Hi:

We are looking for some details on SBC and how they work in terms of call
flows etc. Any pointers?

Also, does someone know of an actual implementation of ICE for NAT/FW
traversal. It could be either commercial or open-source. Something that we
could test for performance. Any help would be appreciated.

Dr. Samir Chatterjee

130 East 9th Street

Claremont, CA 91711

(P) 909-607-4651

(F) 909-621-8564

Subject: Re: [Sipping] Details on SBC
From: "James M. Polk" <[email-masked]>
To: "Samir Chatterjee" <[email-masked]>, <[email-masked]>
Date: Fri, 6 May 2005 18:45:20 -0500

At 03:37 PM 5/6/2005 -0700, Samir Chatterjee wrote:
>Hi:
>
>We are looking for some details on SBC and how they work in terms of call 
>flows etc. Any pointers?

SIP is a peer-to-peer protocol with defined elements (UA, UAC, UAS, Proxy, 
Registrar, etc); an "SBC" is not one of them.

SBC - as in "Session Border Controller" - is a marketing term.

There was a ADHOC BoF at the November (2004) IETF to discuss the 
requirements for SBC - to see if there were sufficient interest and 
sufficiently different requirements on the SIP protocol that energy ought 
to be spent doing a proper gap analysis for those requirements and openly 
discuss in the SIPPING WG what should be done about those gaps. There are 
two individual IDs discussing the requirements for SBCs in SIP as a result 
of this BoF:

draft-camarillo-sipping-sbc-funcs-00.txt
draft-bhatia-sipping-sbc-00

Both IDs were discussed at the last IETF meeting (March 05) in Minneapolis 
for a total of 10 minutes. I don't remember anything especially important 
coming out of those discussions. The notes of the meeting state the two IDs 
will be merged into one for the next meeting.

One of the problems I see (from my point of view) is the current plethora 
of definitions for what an SBC is and what an SBC should do/accomplish. It 
appeared to me in the BoF that nearly everyone in the room had a differing 
opinion on this one question - so there was not much progress that night.

An SBC can be as simple as a SIP Proxy (RFC 3261) with various levels of 
state maintained per session and/or per dialog. These various levels are 
attributed to the differing definitions for what an SBC is to do.

- Some wanted NAT traversal to be solved by SBCs..
- Some wanted IPv4 to IPv6 conversion to be solved by SBCs...
- Some wanted SBCs to be what some of us thought was defined as a Middlebox 
from the MIDCOM WG efforts (that weren't too successful)...
- Some wanted SBCs to terminate media streams and regenerate those streams 
out the other side of the SBC for control and privacy purposes...
- Some wanted SBCs to terminate encrypted media flows on one side of the 
SBC and initiate new encrypted corresponding ones on the other side of the 
SBC for control and privacy purposes...
- Some thought an SBC could solve an administrative domain's QoS issues for 
voice and video traffic...

The message types in the messages flows you seek will be highly dependent 
on what you want an SBC to accomplish from the list above (and other items 
not on this list).

Question to you - what combination of functions do you want an SBC to 
accomplish?

 From that or from those functions - you ought to be able to build the 
flows if you know SIP.

>http://fac.cgu.edu/~chatters

cheers,
James

                                 *******************
                 Truth is not to be argued... it is to be presented.

                      Alas, few *truths* exist without the math.

                             ...all else is a matter of perspective