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[H.323-SIP/Internet] Re: H323/SIP Interworking - way forward
by Orit Levin 02 Mar '00

02 Mar '00

Hello guys! I have exactly same point of view on this path. I would like to be sure that we are talking about the same path. In my understanding (1) and (3) are the same combined (GK and SIP Server) entity (2) is a GK++ being able to talk to SIP Server using SIP only(?) (4) is a SIP Server++ being able to talk to GK using RAS (?) using Annex G/H.225.0 (?) Based on this I would vote for (1) and (3) only (which are the same). "Now, to thin it some more..." Considerations in regards to GK Routed/Direct modes and SIP Proxy flavors ... I vote for - GK Routed mode only - SIP Server having a logic of Statefull Proxy, Registrar and Redirect Server Regards, Orit Levin RADVision Inc. 575 Corporate Drive Suite 420 Mahwah, NJ 07430 Tel: 1 201 529 4300 (230) Fax: 1 201 529 3516 www.radvision.com orit(a)radvision.com -----Original Message----- From: Paul E. Jones <paul.jones(a)ties.itu.int> To: sip-h323(a)egroups.com <sip-h323(a)egroups.com> Date: Thursday, March 02, 2000 2:44 AM Subject: [sip-h323] Re: H323/SIP Interworking - way forward >David, > >Dave Walker suggested removing the first 5 scenarios. I'd agree with that >recommendation. > >Now, to thin it some more... > >Would it not be a reasonable thing to state that interworking between H.323 >networks/devices and SIP networks/devices should be performed by either a GK >or proxy that contains the interworking functions. If folks agree with >that, then we could just have these scenarios: > >HT-----GK/IWF---------------------------ST >HT-----GK/IWF--------------------SR-----ST >HT-----------------------------SR/IWF---ST >HT-----GK----------------------SR/IWF---ST > >Of course, the first two and the last two above are virtually identical. If >the IWF is designed appropriately, there should be no need to make a special >case for #2 and #4 above. > >The reason I would propose this is that it makes sense to collocate the >interworking function within such a device. Additionally, it removes burden >(both new signaling procedures and complexity) from the endpoints, which I >think should be a goal. > >Paul > >----- Original Message ----- >From: "Wang, Dave" <dwang(a)nuera.com> >To: <sip-h323(a)egroups.com> >Sent: Wednesday, March 01, 2000 9:53 AM >Subject: [sip-h323] Re: H323/SIP Interworking - way forward > > >> I 2nd Christian's 4 things and their ordering. >> >> We have started working on the 1st 3 things in IMTC aHIT and ETSI TIPHON, >> but would definitely use more input. >> >> Therefore, could we start having some suggestion and discussion here on >the >> 1st thing : "Architecture and Call Scenarios" ? >> >> There was a very short discussion in this thread about "combination" in >> January started by Joon Maeng, and Kundan Singh. Here is a set of >> combinations that I've expanded from that discussion. I don't mean to make >> the scenarios more comprehensive and complicated. I'm just trying to show >> the various combinations and ask whether we can explicity decided to >ignore >> some of them : >> >> HT-------(H.323)----------------------------------HT >> >> ST------------------------------------(SIP)-------ST >> >> HT---GK--(H.323)----------------------------------HT >> >> ST------------------------------------(SIP)--SR---ST >> >> HT-------(H.323)--IWF-----------------(SIP)-------HT >> >> HT-------(H.323)--IWF-----------------(SIP)-------ST >> >> HT---GK--(H.323)--IWF-----------------(SIP)-------ST >> >> HT---GK--(H.323)--IWF-----------------(SIP)--SR---ST >> >> HT-------(H.323)--IWF-----------------(SIP)--SR---ST >> >> HT-------(H.323)--IWF---(SIP)---IWF--(H.323)------HT >> >> ST--------(SIP)---IWF--(H.323)--IWF---(SIP)-------ST >> >> HT == H.323 Terminal >> ST == SIP Terminal >> GK == H.323 Gate Keeper >> SR == SIP Server >> IWF == SIP/H.323 Inter-working Function >> >> Its has already been pointed out that we should also include Clearing >House >> in the scenarios, however, may be we should have some more discussion and >> possibly some thinning down before thickening it up yet. >> >> >> > -----Original Message----- >> > From: Christian Groves [mailto:Christian.Groves@ericsson.com] >> > Sent: Wednesday, March 01, 2000 2:43 AM >> > To: SG16; sip-h323 >> > Subject: [sip-h323] H323/SIP Interworking - way forward >> > >> > >> > G'Day all, >> > >> > The [H.323-SIP/Internet] thread has lead to some interesting >> > discussion. >> > Being personally involved in the H248 "success" and having actually >> > having had to fight through the process of having to work between SG16 >> > and IETF I think there's a few steps that need to be taken >> > before we go >> > into mapping information elements. >> > >> > I believe the first thing we need to do is define what >> > architecture and >> > call scenarios we are working with. H323 has several architectural >> > elements, SIP is not so strong on architecture so we need to show what >> > elements are talking to each other. Only then we can define what >> > interfaces need to be interworked. In H248 this was relatively easy as >> > the interface was between an MGC and MG. The H323-SIP >> > interworking would >> > be another degree of difficulty as there are potentially several >> > interfaces. This architecture work would not slow down the work but >> > would lead to a structured way of working were people agree >> > on a problem >> > space. One of the issues with H248 was that the problem space was not >> > agree on and we went back and forth trying to figure out >> > where we were. >> > >> > As I mentioned at the SG16 I invite people to make contributions on >> > this. Anything more detailed at this stage I believe is counter >> > productive. Even Orit's first proposal I think is too detailed at this >> > stage. Look at the early H248 work where we had many detailed >> > protocols. >> > There was an inordinate amount of work spent (and many late nights) >> > trying to get from details to architecture. Then we had to go >> > back again >> > and define the protocol. >> > >> > The 2nd thing to do is to define the set of capabilities we intend to >> > interwork. This needs to be a clear statement of scope. Interworking >> > basic audio with no conferencing and services is >> > significantly different >> > than interworking full audio, video and data conferencing. In H248 the >> > scope was so large that people were working on completely different >> > things without appreciating the other people's requirements. >> > >> > Thirdly, we must choose our base. What H323version will be interwork >> > with what SIP flavour and functionalities? Of course in today's world >> > there needs to be flexibility to address new functionality but we >> > shouldn't add a new work item every time of version 0 of an internet >> > draft from Joe Bloggs comes out. >> > >> > Fourthly, I believe that once the above is done, then we have a very >> > good idea of what functional interworking work needs to be >> > done. Once we >> > have an idea of the work we can also figure out where the >> > responsibilities would lie. >> > >> > Once we know the work and who is responsible for the work then we MUST >> > make sure this is agreed upon and documented in both the ITU >> > and IETF by >> > the people who can make decisions. Too many things were hidden in the >> > H248 work and people that could make decisions were not at the >> > appropriate meetings. >> > >> > Finally we can then produce the detailed documents in a way that >> > everyone understands. >> > >> > I do think that at the end of the day H.248 was a success and that the >> > co-operation between the IETF and ITU was made to work. This >> > was because >> > of the large amount of work and sacrifices made by a few >> > individuals and >> > companies who wanted to make this happen. Many of the individuals >> > working on H248 will probably contribute on H323/SIP interworking so >> > lets learn from the mistakes and have another go at making H323-SIP >> > interworking work without having to kill ourselves to achieve >> > the goal. >> > >> > Cheers, Christian >> > >> > -------------------------------------------------------------- >> > ---------- >> > To Post a message, send it to: sip-h323(a)eGroups.com >> > To Unsubscribe, send a blank message to: >> > sip-h323-unsubscribe(a)eGroups.com >> > >> > -------------------------------------------------------------- >> > ---------- >> > Shabang!com is the place to get your FREE eStore, Absolutely FREE >> > Forever. If you have any desires to sell your products or services >> > online, or you want to expand your customer base for FREE, Come check >> > out Shabang!com FREE eStores! >> > http://click.egroups.com/1/1299/2/_/302437/_/951907402/ >> > >> > -- Easily schedule meetings and events using the group calendar! >> > -- http://www.egroups.com/cal?listname=sip-h323&m=1 >> > >> > >> >> ------------------------------------------------------------------------ >> To Post a message, send it to: sip-h323(a)eGroups.com >> To Unsubscribe, send a blank message to: sip-h323-unsubscribe(a)eGroups.com >> >> ------------------------------------------------------------------------ >> GET A NEXTCARD VISA, in 30 seconds! Get rates >> as low as 0.0% Intro APR and no hidden fees. >> Apply NOW! >> http://click.egroups.com/1/969/2/_/302437/_/951922564/ >> >> -- 20 megs of disk space in your group's Document Vault >> -- http://www.egroups.com/docvault/sip-h323/?m=1 >> >> > > >------------------------------------------------------------------------ >To Post a message, send it to: sip-h323(a)eGroups.com >To Unsubscribe, send a blank message to: sip-h323-unsubscribe(a)eGroups.com > >------------------------------------------------------------------------ >You have a voice mail message waiting for you at iHello.com: >http://click.egroups.com/1/2130/2/_/302437/_/951983045/ > >-- Create a poll/survey for your group! >-- http://www.egroups.com/vote?listname=sip-h323&m=1 > >

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Errors / ambiguities / problems found in specs at last week's int erop
by Reinhard Scholl 02 Mar '00

02 Mar '00

The following errors / ambiguities / problems were reported at last week's ETSI-TIPHON/IMTC interop event at ETSI: - Terminal capabilities for G.729 and G.729 Annex A. Though mutually compatible, TCS often fails if vendors only specify support for one or the other. E.g. 729 <--> 729a should work but TCS fails. - H323: GK cannot increase TTL in RCF. Mandatory parameters of type SEQUENCE OF ... can have empty list. - H.225 says that call reference value should be same in ARQ and SETUP. H.323 says that call reference value should be different in ARQ and SETUP. - In H.323, the destination address in UUIE in SETUP is mandatory, in H.225.0 it is not. - H.245: if a capability being sent includes G.711 "20 msec", the other side may think that the sender supports both "20 msec" and "10 msec" rates. But it can be that the originator supports only 20 msec. Ambiguity. - MCU should probably also have "prefix", not just the gateway. - Need BE message formats so that packet dumps can be quickly interpreted. - When using a GK, should the CRV in the admission and setup be the same? Reinhard Scholl ETSI

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Progress syntax changed v2 to v3?
by Paul Long 02 Mar '00

02 Mar '00

It looks like the syntax for Progress changed between H.225.0v2 and v3. Seems like this would present some rather basic interoperability problems. Do I simply have the wrong syntax for v3? This is the syntax for Progress in the published H.225.0v2 Recommendation from the ITU: Progress-UUIE ::= SEQUENCE { protocolIdentifier ProtocolIdentifier, destinationInfo EndpointType, h245Address TransportAddress OPTIONAL, callIdentifier CallIdentifier, h245SecurityMode H245Security OPTIONAL, ..., tokens SEQUENCE OF ClearToken OPTIONAL, cryptoTokens SEQUENCE OF CryptoH323Token OPTIONAL, fastStart SEQUENCE OF OCTET STRING OPTIONAL, } ...and this is the syntax for the same type in v3: Progress-UUIE ::= SEQUENCE { protocolIdentifier ProtocolIdentifier, destinationInfo EndpointType, h245Address TransportAddress OPTIONAL, callIdentifier CallIdentifier, h245SecurityMode H245Security OPTIONAL, tokens SEQUENCE OF ClearToken OPTIONAL, cryptoTokens SEQUENCE OF CryptoH323Token OPTIONAL, fastStart SEQUENCE OF OCTET STRING OPTIONAL, ..., multipleCalls BOOLEAN, maintainConnection BOOLEAN } Paul Long Smith Micro Software, Inc.

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Re: H.323 Annex D
by Francois Audet 02 Mar '00

02 Mar '00

I will seriously consider pulling Annex D into the main document. It makes my life a bit easier, too. However, I suppose it's worth noting which version of H.323 an Annex will work with in general. I have had similar inquiries about Annex E and Annex F. Perhaps a new section in the Implementers Guide is in order to address those issues? I think that it should be in the summary of the Recommendation, if we pusblish it separatly. Not everybody reads the implementor's guide (although they should). That is what we have done for H.323 to relate it to different versions of H.225.0 and H.245.

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Re: Errors / ambiguities / problems found in specs at last week's int erop
by Hutton, Charles 01 Mar '00

01 Mar '00

Paul: 729 and 729A do indeed use the same encoder. Only the decoder is different. Performance of 729A is poorer, particularly with respect to tandeming. I can see that it may sometimes be beneficial to control whether the 729 or 729A algorithm (if a choice is available) is used by the decoder in order to prevent significant degradation of audio quality. If that is a real scenario, then it becomes more than "a local issue". Perhaps others can comment on the "realness" of this possibility. Charles (Chuck) Hutton Strategic Architecture Engineering Wireless Local Technology Group AT&T Wireless Services PO Box 97059 Redmond, WA 98073 (USPS only) 9461 Willows Road Redmond, WA 98052 (FEDEX/UPS) 425-702-2938 Voice 425-702-2518 FAX charles.hutton(a)attws.com > ---------- > From: Paul Long[SMTP:plong@SMITHMICRO.COM] > Reply To: Mailing list for parties associated with ITU-T Study Group > 16 > Sent: Wednesday, March 01, 2000 10:00 AM > To: ITU-SG16(a)mailbag.cps.intel.com > Subject: Re: Errors / ambiguities / problems found in specs at last > week's int erop > > Reinhard, > > I have responded to each of the items you listed. > > - I've wondered myself why there is a separate codepoint for G.729a. From > my > understanding, the use of G.729 or G.729a is a local issue and does not > change the bits on the wire. Maybe we need to state in a future version of > H.323 that they are equivalent with respect to signaling. > > - Are you saying that a GK cannot return a TTL in RCF that is larger than > the TTL in the corresponding RRQ or that it cannot subsequently increase > the > TTL without first having received a lightweight RRQ? I believe that a GK > could return a larger value, but you are correct that there is no way for > it > to update this value without responding to a lightweight RRQ. > > I don't see how the mandatory-parameters issue is related to TTL. > Regardless, this points out a general weakness in semantics for later > additions to H.245 (since H.245v2) and especially H.225.0. IMO, the > description of all SEQUENCE OF and SET OF components should include the > semantics for these situations, even if it is "obvious" to the author what > the semantics should be: > - OPTIONAL component whose encoding is absent > - zero components (empty) > - exactly one component > - more than one component > - component order (we should also use SEQUENCE OF and SET OF where > appropriate) > > We continue to have interoperability problems due to the differing > interpretations as to what these mean. > > - Regarding call reference value, since H.323 is the top-level > Recommendation that references H.225.0, if there is a conflict, H.323 is > always normative. This is true in all referencing relationships between > Recommendations, e.g., between H.225.0 and Q.931. > > - I can't find in H.323 where destinationAddress is required. H.225.0v2 > does > require it, though, "if available" (whatever that means). > > - The audio framing expressed in H.245 is _not_ ambiguous. It is clearly > stated that this is the maximum framing. B.2.2.6/H.245v5: "When an H.225.0 > multiplex is used, these numbers indicate the maximum number of audio > frames > per packet." The problem is that some _implementations_ do not support > variable framing, e.g., some DSPs used in GWs can only process 30ms > frames. > Possible solutions: "fix" decoders so that they support variable framing, > reframe into fixed-size frames before passing along to decoder, add > ability > to express fixed framing in H.245. > > - MCU prefix. I surprisingly have nothing to say about this one. :-) > > - What is a "BE message format?" > > - CRV. Wasn't this already described in a previous item? > > Paul Long > Smith Micro Software, Inc. > > -----Original Message----- > From: Reinhard Scholl [mailto:Reinhard.Scholl@etsi.fr] > Sent: Wednesday, March 01, 2000 10:34 AM > To: 'h323implementors(a)imtc.org'; 'ITU-SG16(a)MAILBAG.INTEL.COM'; > TIPHON_WG6 > Subject: Errors / ambiguities / problems found in specs at last week's > int erop > > > > The following errors / ambiguities / problems were reported at last > week's > ETSI-TIPHON/IMTC interop event at ETSI: > > > - Terminal capabilities for G.729 and G.729 Annex A. Though mutually > compatible, TCS often fails if vendors only specify support for one or > the other. E.g. 729 <--> 729a should work but TCS fails. > > - H323: GK cannot increase TTL in RCF. Mandatory parameters of type > SEQUENCE OF ... can have empty list. > > - H.225 says that call reference value should be same in ARQ and SETUP. > H.323 says that call reference value should be different in ARQ and > SETUP. > > - In H.323, the destination address in UUIE in SETUP is mandatory, in > H.225.0 it is not. > > - H.245: if a capability being sent includes G.711 "20 msec", the other > side may think that the sender supports both "20 msec" and "10 msec" > rates. But it can be that the originator supports only 20 msec. > Ambiguity. > > - MCU should probably also have "prefix", not just the gateway. > > - Need BE message formats so that packet dumps can be quickly > interpreted. > > - When using a GK, should the CRV in the admission and setup be the > same? > > > Reinhard Scholl > ETSI >

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[Robustness] telecon today! March 1, 2000 at 11AM EST USA
by Maureen Stillman 01 Mar '00

01 Mar '00

This is a reminder that the robustness teleconference will be held today at 11AM EST USA. Please join us. The dial in number is: (613)688-2795 The passcode is: 1235# (you must put in the pound sign) Agenda: 1) Discussion of the Robutness Framework document outline (attached) and 2) Solicit volunteers to fill in text for the outlined sections <<Robustness Framework 01.ZIP>> -- maureen Maureen Stillman Member of Scientific Staff Voice: (607)273-0724 x62 Nokia IP Telephony Fax: (607)275-3610 127 W. State Street Mobile: (607)227-2933 Ithaca, NY 14850 e-mail: maureen.stillman(a)nokia.com www.nokia.com

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[sip-h323] H323/SIP Interworking - way forward
by Christian Groves 01 Mar '00

01 Mar '00

G'Day all, The [H.323-SIP/Internet] thread has lead to some interesting discussion. Being personally involved in the H248 "success" and having actually having had to fight through the process of having to work between SG16 and IETF I think there's a few steps that need to be taken before we go into mapping information elements. I believe the first thing we need to do is define what architecture and call scenarios we are working with. H323 has several architectural elements, SIP is not so strong on architecture so we need to show what elements are talking to each other. Only then we can define what interfaces need to be interworked. In H248 this was relatively easy as the interface was between an MGC and MG. The H323-SIP interworking would be another degree of difficulty as there are potentially several interfaces. This architecture work would not slow down the work but would lead to a structured way of working were people agree on a problem space. One of the issues with H248 was that the problem space was not agree on and we went back and forth trying to figure out where we were. As I mentioned at the SG16 I invite people to make contributions on this. Anything more detailed at this stage I believe is counter productive. Even Orit's first proposal I think is too detailed at this stage. Look at the early H248 work where we had many detailed protocols. There was an inordinate amount of work spent (and many late nights) trying to get from details to architecture. Then we had to go back again and define the protocol. The 2nd thing to do is to define the set of capabilities we intend to interwork. This needs to be a clear statement of scope. Interworking basic audio with no conferencing and services is significantly different than interworking full audio, video and data conferencing. In H248 the scope was so large that people were working on completely different things without appreciating the other people's requirements. Thirdly, we must choose our base. What H323version will be interwork with what SIP flavour and functionalities? Of course in today's world there needs to be flexibility to address new functionality but we shouldn't add a new work item every time of version 0 of an internet draft from Joe Bloggs comes out. Fourthly, I believe that once the above is done, then we have a very good idea of what functional interworking work needs to be done. Once we have an idea of the work we can also figure out where the responsibilities would lie. Once we know the work and who is responsible for the work then we MUST make sure this is agreed upon and documented in both the ITU and IETF by the people who can make decisions. Too many things were hidden in the H248 work and people that could make decisions were not at the appropriate meetings. Finally we can then produce the detailed documents in a way that everyone understands. I do think that at the end of the day H.248 was a success and that the co-operation between the IETF and ITU was made to work. This was because of the large amount of work and sacrifices made by a few individuals and companies who wanted to make this happen. Many of the individuals working on H248 will probably contribute on H323/SIP interworking so lets learn from the mistakes and have another go at making H323-SIP interworking work without having to kill ourselves to achieve the goal. Cheers, Christian ------------------------------------------------------------------------ To Post a message, send it to: sip-h323(a)eGroups.com To Unsubscribe, send a blank message to: sip-h323-unsubscribe(a)eGroups.com ------------------------------------------------------------------------ Shabang!com is the place to get your FREE eStore, Absolutely FREE Forever. If you have any desires to sell your products or services online, or you want to expand your customer base for FREE, Come check out Shabang!com FREE eStores! http://click.egroups.com/1/1299/2/_/302437/_/951907402/ -- Easily schedule meetings and events using the group calendar! -- http://www.egroups.com/cal?listname=sip-h323&m=1

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MAC21 Art Fair 2000
by feria＠MAC21.COM 29 Feb '00

29 Feb '00

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Re: [H.323-SIP/Internet] The reason.
by Roy, Radhika R, ALARC 29 Feb '00

29 Feb '00

Hi, Bahman and Orit, I agree with Bahman. Orit, would you please clarify more what do you expect with respect to your proposals 1 and 2? Best regards, Radhika > -----Original Message----- > From: Bahman Mobasser [SMTP:bahman.mobasser@ALCATEL.FR] > Sent: Tuesday, February 29, 2000 11:23 AM > To: ITU-SG16(a)MAILBAG.INTEL.COM > Subject: Re: [H.323-SIP/Internet] The reason. > > Orit- > > In my opinion what would most useful would a restrictive interpretation of > 1, and I will explain: what is needed is the specification of an H.323-SIP > call. Depending on the network configuration assumptions (i.e., what > equipment is between the two end-points), the mapping needs will become > clear. > > On this option I share your point of view- while this may be politically > incorrect, I think inviting everybody to the Picnic does not necessarily > advance things. If one organisation (IETF) has taken the lead in doing > this, > then the best thing to do is to encourage them by taking proposals there. > > 2 confuses me too much and sends, in my opinion, completely the wrong > signals and should be avoided. > > Bahman > > ----------------------------------------------------- > Bahman Mobasser Tel: +33 1 30771608 > Alcatel Mobile: +33 6 12091822 > 10 rue Latécoère Fax: +33 1 30779914 > 78140 Vélizy Voice & Fax Mail: +33 1 5301 0789 > France Roaming email: Bahman(a)Bahman.org > ----------------------------------------------------- > > [[ MAPI 1.0 storage : 4140 in winmail.dat ]] > > -----Original Message----- > From: Mailing list for parties associated with ITU-T Study Group 16 > [mailto:ITU-SG16@mailbag.cps.intel.com] On Behalf Of Orit Levin > Sent: lundi 28 février 2000 17:25 > To: ITU-SG16(a)mailbag.cps.intel.com > Subject: Re: [H.323-SIP/Internet] The reason. > > Hello! > I can see two (hardly overlapping) directions to move forward: > (1) H.323 - SIP interworking by mapping/translation > (2) Definition of how H.323 takes use of Internet services being defined > by > IETF > > In the regards to (1), my personal preference would be to leave this work > under the IETF process. I suspect they had a perfect reason being the > first > to start this work. It doesn't mean SG16 shouldn't prevent them from > making > mistakes on H.323 side. > > In regards to (2), I think it has to be addressed by H.323 as a part of > H.323. I would love to see more comments on this (less political) part of > the work. > > In the meanwhile I am putting all the suggestions and alternatives in the > updated paper (which is not attached yet). > Best Regards, > Orit Levin > RADVision Inc. > 575 Corporate Drive Suite 420 > Mahwah, NJ 07430 > Tel: 1 201 529 4300 (230) > Fax: 1 201 529 3516 > www.radvision.com > orit(a)radvision.com > -----Original Message----- > From: Henning Schulzrinne <hgs(a)CS.COLUMBIA.EDU> > To: ITU-SG16(a)MAILBAG.INTEL.COM <ITU-SG16(a)MAILBAG.INTEL.COM> > Date: Sunday, February 27, 2000 10:57 PM > Subject: Re: [H.323-SIP/Internet] The reason. > > > >Since my name popped up in a recent email discussion, a few remarks: > > > >1) Yes, the SIP-H.323 list was created by myself; it is open to anybody. > >While its creation was triggered by the interest generated by a proposal > >(Internet draft) written by Kundan Singh (a student of mine) and myself, > >it is open to any discussion related to the topic of interworking. > >(Discussions about the relative merits of protocols are decidedly less > >appreciated.) Whether people use this mailing list or create something > >new and different is obviously beyond my control. > > > >The creation of the mailing list was done without any implied IETF > >endorsement or even endorsement of other SIP authors. (I hope they don't > >mind too much...) > > > >2) In this context, there is one important difference between the ITU > >and IETF standardization process which particularly affects this > >discussion. While all ITU recommendations are "standards", most IETF > >RFCs are not. For the case at hand, it would probably be considered > >inappropriate for a standards-track RFC except, with lots of stretch of > >the imagination, a BCP (best current practice). If an interoperability > >document does get published within the IETF, it is likely to appear as > >an Informational or possibly Experimental RFC. In this particular case, > >as long as the signaling gateway looks like a valid SIP or H.323 entity, > >the other SIP and H.323 entities won't know that it is talking to the > >"other side" (you can insert "dark side" or "the enemy" if you are so > >inclined). > > > >As our initial document points out, there is probably a range of > >solutions that satisfy this basic criterion, depending on (for example) > >to what extent X entities are visible in Y land. > > > >In my view, publishing any such interoperability document has the > >primary benefit of saving implementors of such devices, should they > >become popular, a bit of thinking time and maybe avoid some pitfalls. > >They are not strictly *necessary* - anybody could derive one of the > >modes that we described or something different, as long as it satisfies > >the basic "in Rome, do as the Romans" criterion mentioned earlier. > > > >Thus, given that a standards-track document is not really called for on > >the IETF side, this effort could be significantly simpler than, say, the > >Megaco/H.248 effort. My rough perception is that the IESG will basically > >ask at publication time whether the document suggested as an > >Informational RFC violates IETF protocols (SIP and SDP, in this case). > >If not, and it does no other harm (e.g., broadcasting a RAS-like query > >to all SIP nodes in the Internet or something similarly stupid), the > >IETF process should be relatively straightforward, even without a lot of > >cooperation machinery, liaison agreements and the like. I realize that > >this assessment is probably hopelessly naive, but I am concerned that > >the collective effort expended on meta-discussions is rapidly > >approaching the effort that seems to be necessary to write an > >interoperability document for basic services, including the time to > >implement it. > > > >We'd be happy to provide the infrastructure for meetings, allowing the > >ITU participants to use their H.323 phones to call our SIP phones using > >our gateway implementation :-) No, we won't charge the ITU for these > >translation services :-) > > > >Regards, > > > >Henning

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Re: H.323 Annex D
by Francois Audet 29 Feb '00

29 Feb '00

Paul, do you have a copy of H.245v3? All I can find are v1, v2, v4, v5, v6... -----Original Message----- From: Paul E. Jones [mailto:paul.jones@TIES.ITU.INT] Sent: Monday, February 28, 2000 9:13 PM To: ITU-SG16(a)MAILBAG.INTEL.COM Subject: Re: H.323 Annex D Francois, Actually, I went back to look and we do allow newer versions of H.245 to be used with H.323v2 systems. It was inserted into the H.323 IG in May 1999 and is also in H.323v3. Unfortunately, the text is not as clear as it should be. That's something I will address. You are correct that new additions were made to H.245v6 (as confirmed by Mike Nilsson) to support T.38. I don't recall now what the specific issue were: whether H.245v4 would not work at all or whether the additions were merely improvements. I do remember that at one point, Annex B/T.38 has ASN.1 that differed from H.245-- that was certainly an issue. As far as I know, though, Annex D/H.323 will work with H.245v4. Can anyone else comment? I will seriously consider pulling Annex D into the main document. It makes my life a bit easier, too. However, I suppose it's worth noting which version of H.323 an Annex will work with in general. I have had similar inquiries about Annex E and Annex F. Perhaps a new section in the Implementers Guide is in order to address those issues? Paul ----- Original Message ----- From: Francois Audet <mailto:audet@NORTELNETWORKS.COM> To: ITU-SG16(a)mailbag.cps.intel.com <mailto:ITU-SG16@mailbag.cps.intel.com> Sent: Monday, February 28, 2000 12:18 PM Subject: Re: H.323 Annex D By default, I believe that editor would be me. This annex was intended to work with H.323v2 systems and later, but you are correct that there was no way to specify T.38 until H.245v4. Of course, H.323v2 systems used H.245v3. H.323v3 systems used H.245v3 or higher (the key element). So, I suppose the question is: is H.323v3 required? Surely not, as there are implementations out there. We have argued about whether H.323v2 systems could use later versions of H.245. The outcome was "no"-- perhaps that needs to be revisited. Interesting: I tought H.323v2 used H.245v2... Side issue anyways. There have been recent changes to H.245 ASN.1 to support T.38. At least there have been some proposed changes. Unfortunately, I missed much of that discussion. The meeting report says that those changes were added to H.245v6. Mike, is it true that the T.38-related changes from H.245v4 to H.245v6 were nothing more than additions to H.245-- not "changes", per se. Also, did the proposed changes (from TD8/WP2, I believe) make it into H.245v6? My understanding would be that the changes were introduced in H.245v4, but had mistakes that were corrected in H.245v6. As for Annex D, I am considering just pulling that into the H.323 document, rather than keeping it as a separately published annex-- does anybody object to that? That would certainly address questions related to references going forward. However, we need to reach a decision about the current publication. I suspect we need something for the IG, but the problem is that H.323v2 is "old news" now. What to do.... I would support including Annex D in the main H.323v4 document (wich would imply H.245v6). The other alternatives would be to mandate H.323v4/H.245v6 in Annex D. But I prefer the first alternative.

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