Jean-Francois, Here are a few benefits for using v3: H.323v3 introduces new fields to allow the GK to signal whether Annex E should be used or not. For build large-scale devices, Annex E is definitely worth considering. (Annex E was written for V2, but related RAS fields were added in v3.) It is possible to use the same TCP connection for multiple calls. Text was added to explain the use of Lightweight RRQs (this may have been in the IG, but I can't recall). A number of things are better explained, revisions have been made via the IG that may result in interworking issues if the latest texts (including the IG are not followed). Indeed, things should be backward compatible, but the clarifications are important, as they were obviously points of confusion. Version 4 has even more. Here's a few: * Gateway decomposition section * Support for new services and features * Annex L, Annex K, H.450.x, etc. * Generic Extensibility Framework * Additive Registrations * Alternate Gatekeeper usage fully defined * Usage Information Reporting * Endpoint Capacity Reporting * Desired protocol indication * Reporting call status with multiple IRRs * Call Linkage * Early H.245 * Support for pre-paid calling cards You can definitely see some advantages to v4. Probably the most important introduction in V4 is the Generic Extensibility Framework. With that, we can now add new features to the H.323 protocol specification that the signaling entities in the middle of the call can remain completely ignorant about. This allows us to add new features that work end to end without forcing the intermediate equipment to be updated-- that's one very good reason for moving to v4. It's quite possible that v4 may serve as the minimum specification for some time to come. Of course, this was possible before with "non-standard" mechanisms, but it is hoped that the GEF will introduce fewer ripples in the H.323 standardization effort and the software development cycle. This extensibility framework may also serve well for feature interaction between SIP and H.323. I realize that feature interaction is not an immediate goal, but it's nice to have the foundation in place to try to utilize it. That's why I suggested at the meeting to go with the latest: v4. It's true that the differences between v2 and v3 are small, but a few scalability issues were addressed. Since signaling interworking is not a major CPU consumer, I would think you'd want to take every possible step to increase the number of calls handled on a single box. That could easily go over the number of sockets the box can support. So using Annex E or carrying multiple calls over a call signaling channel is desirable. Of course, I realize that NetMeeting does not support these features, but I think that heavier consideration should be given to other H.323 entities. I cannot recommend trying to offer residential phone service using H.323v2 where SIP interworking is required: it's not nearly as scalable as v3 since SIP interworking forces all calls to be directed to one box or a few boxes. SIP works well there, but one really needs Annex E/H.323 to get comparable scaling ability from H.323. Paul ----- Original Message ----- From: "Jean-Francois Mule" <jfmule@clarent.com> To: <paulej@packetizer.com> Cc: "Wang, Dave" <dwang@nuera.com>; "aHit! IMTC (E-mail)" <ahitag@imtc.org> Sent: Tuesday, August 29, 2000 12:53 PM Subject: RE: [sip-h323] SIP-H.323 IWF protocol requirements

Paul, Based on the current aHit IWF requirements, could help the group identify what particular h323v3 functionality would be mandatory for the IWF. If we can meet the requirements with v2, then we should mandate v2 which means also that v3 implementations will meet the requirements since there is some backward compatibility.

Jean-Francois Mule Clarent Corp.

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-----Original Message----- From: Wang, Dave [mailto:dwang@nuera.com] Sent: Tuesday, August 29, 2000 8:59 AM To: aHit! IMTC (E-mail) Subject: FW: [sip-h323] SIP-H.323 interworking Requirements Draft

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-----Original Message----- From: Paul E. Jones [mailto:paulej@packetizer.com] Sent: Monday, August 28, 2000 11:53 PM To: Roy, Radhika R, ALCOO; sip-h323@egroups.com; ITU-SG16@mailbag.cps.intel.com Subject: Re: [sip-h323] SIP-H.323 interworking Requirements Draft

Radhika,

A few months ago, I published the final set of ASN.1 corrections for H.323v3 to the ITU-T SG16 mailing list and to the IMTC H.323 mailing list. I also contact 11 companies that have H.323v3 products or products in development that I was aware of.

There are certainly plenty of v3 implementations in progress and it's important to be prepared for those implementations. H.323v4 will be approved in November and I expect even quicker adoption of that Recommendation, because it introduces a lot of new functionality.

I think what the group should try to strive for is a specification that will work with the most recent version of H.323-- H.323v4. Of course there will be few implementations, but there are not a large number of new mandatory features. (I don't have a list handy.)

For a "bigger picture" view of what's new in the various versions of H.323, see: http://www.packetizer.com/iptel/h323/

Best Regards, Paul

----- Original Message ----- From: "Roy, Radhika R, ALCOO" <rrroy@att.com> To: "Roy, Radhika R, ALCOO" <rrroy@att.com>; <sip-h323@egroups.com> Sent: Monday, August 28, 2000 10:32 PM Subject: RE: [sip-h323] SIP-H.323 interworking Requirements Draft

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Hi, Everyone:

Here is my view as stated below:

It is very difficult to find any vendor to support H.323 version 3. Many companies are now testing vendor implementations of H.323 version 2, and it is also reported that multivendor interoperability at the version 2 level is still problematic. In many cases, no promise has been obtained from the major vendors when they will support version 3. It may be very nice to have SIP/H.323 v3 interworking, but we think SIP/H.323 v2 interworking should come first.

Considering all factors, I think that we should keep our first interworking requirements to support H.323 version 2 as defined in the present draft (while we may consider for H.323 version 3 in the future).

So, I recommend that we should make any changes in the present draft.

Best regards, Radhika R. Roy AT&T +11 732 420 1580

-----Original Message----- From: Roy, Radhika R, ALCOO [mailto:rrroy@att.com] Sent: Sunday, August 27, 2000 10:32 PM To: sip-h323@egroups.com Subject: [sip-h323] SIP-H.323 interworking Requirements Draft

Hi, Everyone:

I have just returned from the ITU-T SG16 Q.13 (H.323) meeting where our SIP-H.323 Interworking requirement draft was also discussed.

The Q.13 members have strongly recommended that we should consider H.323 version 3 (instead of version 2) for our SIP-H.323 interworking work.

We would appreciate if you would kindly provide your comments on the point.

Best regards, Radhika R. Roy AT&T +1 732 420 1580 rrroy@att.com

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