Francois,
I do not take your arguments personally. But my statements are statements of fact, nothing more.
Allow me to comment on your statements.
Paul wrote:
It's not an impossible task, but one that may lead to tremendous debate.
It
is quite obvious that some members of the ITU and some members of the
IETF
have very basic philosophical differences. I can tell you that some
members
of the IETF will quickly reject anything the ITU does to standardize interoperability. I can also tell you that some of those members will
also
reject anything ETSI does, as well.
Couldn't you think that this may actually have something to do with the fact that 3-4 years of interoperability trials for H.323 in Etsi/ITU/IMTC have lead to an amount of interoperability that was acheived in 1 or 2 bake-offs for SIP.
First of all, I should probably make it very clear that I have worked on both H.323 and SIP projects. I am aware of the stengths and weaknesses of each. There is a generally feeling that SIP is so easy and H.323 is much harder. In some ways, that's true-- in particular, the ASN.1 PER requires work. However OSS provides an excellent set of tools for that, so that's really a non-issue.
H.323 supports multipoint, multimedia conferences. With H.323, there is the concept of a "conference" in which voice, video, and audio may be used. SIP, on the other hand, is a "session initiation protocol". It is not a conferencing protocol. In fact, since the BYE message is optional, SIP doesn't even exist after the remote party accepts the INVITE message and the ACK is returned. From that point forward, the "session" is nothing more than RTP streams flowing.
There have been many H.323 interoperability events. Yes, there have been more problems than at SIP bake-offs, but that's because H.323 is a more complete system with a little more complexity to support multipoint voice, video, and data. But those interop events continue, because the standard continues to grow and evolve-- not because all of the previous events were total failures.
Presently, there are literally millions of H.323 devices out there in the world in production networks. There are major carriers using H.323 to provide VoIP-- it's real. As far as I know, there is not one single production network running on SIP. Perhaps Level 3 might be using it between MGCs, but that deserves no special bragging rights. Perhaps I am wrong, but whatever SIP networks exist pales in the shadow of H.323.
That going to a SIP backeoff is cheap and attending the ITU-T is outrageously expensive. You can try to depict otherwize, but the basics underlying reasons why the ITU-T is doomed to perpetuously deceive IETF participants are still there ... no rough concencus, no running code, membership fees which lock-out small players, closed-policy on publication of standards, closed mailing lists, shall I go on ?
The ITU does require concensus and that often leads to a larger protocol. Essentially, some folks want one set of features and another group wants another set. The solution-- if they don't conflict, we add both. However, those additions are almost always optional. Essentially, manufacturers get to introduce into the standard what their customers want or need.
As for the price of the ITU... it is a bit expensive, but we do not exclude the public from all meetings. The ITU meetings in Geneva are only for sector members or represetatives of a delegation. If any company wanted to attend the ITU meeting and they were not a sector member, the could most likely contact their government agency (U.S. State department in the US) and ask permission to attend. Most likely, permission would be granted.
During the year, we also have "Rapporteur meetings". Those are completely open to the public and we have had IETFers at those meetings. The mailing list is certainly not closed: Intel runs the mailing list!
As for the cost of the ITU: I have no control over that. The ITU, being part of the United Nations, has a responsibility to make documents available in multiple languages and provide meetings with interpreters. There are costs associated with that. I suppose the fees charges are necessary in order to maintain their facilities and employee the personel necessary in order to produce the various translations.
The interest in interoperability with SIP is presently a one way relationship which comes from the H.323 people. Thus, it is the same H.323 people whi should consider coming to an industry-open, SIP bake-off. You can try talking Henning Schulzrinne into lettin you in. I'm sorry, but we just dont need the ITU-T, ETSI nor the IMTC slowing us down at the IETF ;-)
Actually, the first H.323/SIP interworking effort was started on the IETF side. I'm not sure who started the list, but I know that Henning publicized the mailing list sip-h323@eGroups.com. I believe it's his list.
Your last comment is precisely the kind of attitude I was talking about when I said that "I can also tell you that some of those members will also reject anything ETSI does, as well." It's interesting that members of the ITU will adopt specifications from the IETF or other organizations-- whatever is necessary to meet the requirements-- but that so many IETF people maintain a "holier-than-thou" attitude and are so unwilling to work with other standards bodies.
I think that all of your analysis is rubbish. You could simply bring your stuff at one of the SIP bake-offs and get the feedback you need to go on and experiment a little more with H.323 ... You can try all you want to turn a Gatekeeper into a Proxy server/Redirect server, but it'll probably not happen in the marketplace.
I believe that you have reconfirmed my analysis. Honestly, though, it's not "analysis". It's experience. I have attended IETF meeting and would continue if I had the time. I work with people who do attend the meetings. I know a lot of folks within the IETF and the ITU and I can tell you that there are very basic philosophical differences between the two organizations.
As for turning a GK into a proxy server, it's more the other way around: a proxy server is looking more and more like a Gatekeeper these days. And will you see them converge? Quite possibly-- certainly, they are converging functionally.
This said, I'm sorry for flaming you.
I take no offense. But I do believe this exchange (and the recent H.248/MEGACO fiasco) and demonstrated that it is very difficult for the two organizations to work cooperatively. I am still open to a cooperative effort, because I think that is the best thing for our customers.
Best Regards, Paul E. Jones Editor, H.323 Cisco Systems, Inc.