June 2000 - sg16-avd - lists.packetizer.com

H.323 URL - IANA registration
by Orit Levin 22 Jun '00

22 Jun '00

Chip, I agree and taking care of that. Before the decision where to register H323 url (and after the reading of BCP-35) this is my take on it: To register H323 url under a new ITU tree may be a quicker process and more flexible for later changes. The disadvantage is that we (ITU) need to define procedures for ITU tree maintenance/"change control". To register H323 url under IETF would require either RFC standard track document (I don't believe in such a thing for H.323) or Informational RFC carefully inspected by IESG for all possible implications. Your opinions, please! 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: Chip Sharp <chsharp(a)CISCO.COM> To: ITU-SG16(a)MAILBAG.INTEL.COM <ITU-SG16(a)MAILBAG.INTEL.COM> Date: Thursday, June 22, 2000 9:14 AM Subject: Re: H.323 URL >I don't disagree with your proposal; however... :-) > >If it is going to be called a URL, it needs to be registered as per >BCP35. Otherwise, use of the term URL will be confusing to the industry. > >Chip > > >At 01:46 AM 6/22/00 -0400, Paul E. Jones wrote: >>Bob, >> >>Perhaps the simplest solution is for the white paper to contain the agreed >>syntax thus far from TD-40, without any of the other content. I agree >>that it is probably illegal to say that the H.323 URL can be copied into >>the e-mail ID field. However, if the syntax following h323: suggested >>that what follows is some generic identifier and its attributes, an e-mail >>address, or telephone number based on the format, then I believe it would >>be valid to say we could copy the e-mail address into that alias >>field. However, I don't know how to interpret the octets following the h323:. >> >>Could we agree to have a section that defines the shows the URL syntax >>without procedure and agree that the procedural text will be added to >>Annex O? I would even suggest to put the URL definition in Annex O, too, >>but we have a timing problem with respect to Annex K-- it needs that >>definition now. >> >>Thoughts? >> >>Paul >> >>>----- Original Message ----- >>>From: <mailto:Robert.Callaghan@ICN.SIEMENS.COM>Callaghan, Robert >>>To: <mailto:ITU-SG16@mailbag.cps.intel.com>ITU-SG16(a)mailbag.cps.intel.com >>>Sent: Monday, June 19, 2000 2:46 PM >>>Subject: Re: H.323 URL >>> >>>Orit, >>> >>>I am not now sure what was agreed to, other that to let TD-40a to move >>>forward. >>> >>>I do agree with the three points in your note. >>> >>>I do not agree that the proposal was limited to Call Control Messages. I >>>see no difference between the use of H.323-URLs on a Web page and the use >>>of H.3233-URLs in Call Control. The one directly leads to the latter. >>> >>>I am not sure if you are implying that only H.323-URL can be used to >>>direct a call to an H.323 destination. If so, I disagree. All alias >>>formats work equally well. My understanding is that Paul Jones wanted >>>the E.164 format of the H.323-URL in order to access the gateway using >>>the H.323 client as a telephony client. This definitely does not point >>>to an H.323 URL. >>> >>>I am afraid that we may not know what we agreed to, other than to >>>proceed. That is why I objected that the URL be included in v4 instead >>>of and annex or appendix. Now our lack of understanding as to what we >>>understood will jeprodice v4 if it remains as is. But that was the >>>agreement, so we must proceed forward. >>> >>>Bob >>> >>> >>>-----Original Message----- >>>From: Orit Levin [mailto:orit@radvision.com] >>>Sent: Monday, June 19, 2000 10:06 AM >>>To: ITU-SG16(a)mailbag.cps.intel.com >>>Subject: Re: H.323 URL >>> >>>Dear all! >>>There are two faces to H323-URL. The first one is when H.323-URL is used >>>as an alias in H.323 Call Control messages. The second is when H.323-URL >>>is used in Web pages or other hyperlinks. (Although, when both are in >>>place, from procedural point of view their order is vice versa.) >>> >>>In my contribution in Osaka, I chose to address "the first case" first. >>>There are number reasons for this: >>>1. URL concept exists in H.323 since version 2. The procedures, how URLs >>>should be used, haven't been defined. This clearly invites >>>interoperability problems. >>>2. H323-URL hasn't been defined at all. This leads to interpretation of >>>other URLs, to be used INSTEAD, while reaching pure H.323 entities! This >>>clearly invites interoperability problems. >>>3. Standard H323-URL can greatly facilitate address translation >>>procedure, when H.323 runs on Internet. >>> >>>As it can be seen from TD-40a, it has been agreed, that H323-URL should >>>be used to POINT TO H.323 DESTINATION. Other URLs may/should be used in >>>H.323 messages to point to other destinations. Personally, I see this >>>approach as the best. Also Bob and Francoise supported this in their last >>>e-mails. Please, lets try not to open already agreed things before the >>>next meeting, jeopardizing by that H.323v4 decision. Specifically on >>>H323-URL topic, we have to clean things (such as the use of email ID >>>alias) and put the basic version onto H.323v4. Then we will have "Annex >>>O" to expand on additional "complimentary to H.323" procedures. >>> >>>One of these procedures is "the second face" of H323-URL: while used in >>>WEB pages. It is clear that H.323-URL should be expanded with additional >>>parameters to be used as such. It is also mentioned in TD-40a. >>>Contributions are mostly welcome. >>> >>>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 >>><http://www.radvision.com>www.radvision.com >>><mailto:orit@radvision.com>orit(a)radvision.com >>>>-----Original Message----- >>>>From: Paul E. Jones <<mailto:paulej@PACKETIZER.COM>paulej(a)PACKETIZER.COM> >>>>To: <mailto:ITU-SG16@MAILBAG.INTEL.COM>ITU-SG16(a)MAILBAG.INTEL.COM >>>><<mailto:ITU-SG16@MAILBAG.INTEL.COM>ITU-SG16(a)MAILBAG.INTEL.COM> >>>>Date: Monday, June 19, 2000 3:27 AM >>>>Subject: Re: H.323 URL >>>> >>>>Francois, >>>> >>>>If I want to provide a means of allowing somebody to call me by placing >>>>a URL on a web page, I need to provide something that can be resolved >>>>universally by H.323 endpoints. Bob mentioned querying a database-- >>>>that's certainly a possibility, assuming that that database contains all >>>>of the information it needs to resolve an address. >>>> >>>>What I am afraid of here is that we are introducing syntax to reach a >>>>resource without defining any procedure. >>>> >>>>If I see this url: >>>><mailto:h323:paulej@packetizer.com>h323:paulej@packetizer.com >>>> >>>>What does that tell the H.323 entity? Is there a GK that is expecting a >>>>LRQ, AccessRequest, or is it something else entirely? Perhaps the right >>>>solution is to define (in normative text) the procedure for using SRV >>>>DNS records to query the packetizer.com domain. >>>> >>>>As Pete rightfully pointed out, an H.323 URL would be the perfect place >>>>to place conference identifiers for multipoint conferences: >>>> >>>><mailto:h323:conf-server1@packetizer.com;cid:XXXX-XXXX-XXXX-XXXX>h323:co nf-server1@packetizer.com;cid:XXXX-XXXX-XXXX-XXXX >>>> >>>> >>>>I think we need to work on the procedural part of this now. Who is >>>>working on that? >>>> >>>>Paul >>>> >>>>>----- Original Message ----- >>>>>From: <mailto:audet@NORTELNETWORKS.COM>Francois Audet >>>>>To: <mailto:ITU-SG16@mailbag.cps.intel.com>ITU-SG16(a)mailbag.cps.intel.com >>>>>Sent: Friday, June 16, 2000 11:48 AM >>>>>Subject: Re: H.323 URL >>>>> >>>>>I would agree with Bob here. >>>>>Using an H.323 URL for a telephone number would imply that you can only >>>>>be >>>>>reached using H.323. Is this you intention? >>>>> >>>>> > -----Original Message----- >>>>> > From: Callaghan, Robert >>>>> [<mailto:Robert.Callaghan@ICN.SIEMENS.COM>mailto:Robert.Callaghan@ICN.SIEMEN S.COM] >>>>> >>>>> > Sent: Friday, June 16, 2000 5:39 AM >>>>> > To: <mailto:ITU-SG16@MAILBAG.INTEL.COM>ITU-SG16(a)MAILBAG.INTEL.COM >>>>> > Subject: Re: H.323 URL >>>>> > >>>>> > >>>>> > Paul, >>>>> > >>>>> > I think that this is getting complicated. >>>>> > >>>>> > I did not envision the use of the H.323-URL to encompase a >>>>> > telephone number. >>>>> > I only conceede for the purpose of progress. >>>>> > >>>>> > I saw the H.323-URL to be an identifier that would be used to access a >>>>> > database. The DNS portion would identify the database, the >>>>> > userID would be >>>>> > the entry in the database. The database would then return >>>>> > the necessary >>>>> > information to complete the call. It is highly propable that this >>>>> > information would include an E.164 or PNP address. This is >>>>> > especially true >>>>> > when the call must be ompleted over the SCN. >>>>> > >>>>> > I saw telephone numbers being defined in the "Tel:" URL >>>>> > defined in RFC2806. >>>>> > This URL covers many of optional fields needed to make an SCN >>>>> > call which are >>>>> > not presently covered in H.323. >>>>> > >>>>> > If we are to have multiple forms of an H.323 URL, I would >>>>> > prefer to have >>>>> > multi-URL IDs. >>>>> > >>>>> > Bob >>>>> > >>>>> > P.S. (By the way, the complex, cover everything, is where the >>>>> > last try at an >>>>> > H.323 URL diaappeared.) >>>>> > >>>>> > ------------------------------------------------------------------ >>>>> > Robert Callaghan >>>>> > Siemens Enterprise Networks >>>>> > Tel: +1.561.923.1756 Fax: +1.561.923.1403 >>>>> > Email: Robert.Callaghan(a)ICN.Siemens.com >>>>> > ------------------------------------------------------------------ >>>>> > >>>>> > >>>>> > -----Original Message----- >>>>> > From: Paul E. Jones >>>>> [<mailto:paulej@packetizer.com>mailto:paulej@packetizer.com] >>>>> > Sent: Friday, June 16, 2000 3:11 AM >>>>> > To: Callaghan, Robert; 'Orit Levin' >>>>> > Cc: Mailing list for parties associated with ITU-T Study Group 16 >>>>> > (E-mail) >>>>> > Subject: Re: H.323 URL >>>>> > >>>>> > >>>>> > Bob, >>>>> > >>>>> > I'm still surprised that you don't want to see the URL expanded... >>>>> > especially to address party number types. Here is is currently: >>>>> > >>>>> > H323-URL = "H323:" user ["@" hostport] >>>>> > user = username | phone-number >>>>> > username = *( unreserved | escaped | "&" | "=" | "+" >>>>> > | "$" | "," ) >>>>> > hostport = host [ ":" port ] >>>>> > host = hostname | IPv4address >>>>> > hostname = *( domainlabel "." ) toplabel [ "." ] >>>>> > domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum >>>>> > toplabel = alpha | alpha *( alphanum | "-" ) alphanum >>>>> > IPv4address = 1*digit "." 1*digit "." 1*digit "." 1*digit >>>>> > port = *digit >>>>> > reserved = ";" | "/" | "?" | ":" | "@" | "&" | "=" | >>>>> > "+" |"$" | "," >>>>> > digits = 1*DIGIT >>>>> > >>>>> > However, to be useful, information that follows the "h323:" should be >>>>> > something in a form that an H.323 Gatekeeper can resolve. >>>>> > Those things >>>>> > include: >>>>> > dialedDigits >>>>> > h323-ID >>>>> > email-ID >>>>> > partyNumber >>>>> > or one of the transportAddress types. >>>>> > >>>>> > This seems to be a reasonable syntax: >>>>> > >>>>> > H323-URL = "H323:" Address >>>>> > Address = AliasAddress / TransportAddress >>>>> > AliasAddress = dialedDigits / h323-ID / email-ID / partyNumber >>>>> > dialedDigits = "dialedDigits=" 1*digit >>>>> > h323-ID = "h323-ID=" 1*OCTET ; UTF-8 string represting the >>>>> > BMPString >>>>> > email-ID = "email-ID=" email-ID-spec >>>>> > partyNumber = e164Number / dataPartyNumber / telexPartyNumber / >>>>> > privateNumber >>>>> > / nationalStandardPartyNumber >>>>> > email-ID-spec = mailbox / group >>>>> > group = phrase ":" [ mailbox ] ";" >>>>> > phrase = 1*word >>>>> > word = atom / quoted-string >>>>> > atom = 1*CHAR ; any CHAR except specials, SPACE and CTLs >>>>> > specials = "(" / ")" / "<" / ">" / "@" ; Must be in quoted- >>>>> > / "," / ";" / ":" / "\" / <"> ; string, to use >>>>> > / "." / "[" / "]" ; within a word. >>>>> > quoted-string = >>>>> > mailbox = addr-spec / phrase route-addr >>>>> > addr-spec = local-part "@" domain >>>>> > local-part = word *("." word) >>>>> > domain = sub-domain *("." sub-domain) >>>>> > sub-domain = domain-ref / domain-literal >>>>> > domain-ref = atom >>>>> > domain-literal = "[" *(dtext / quoted-pair) "]" >>>>> > dtext = 1*CHAR ; Any CHAR excluding "[", "]", "\" & CR, >>>>> > ; & including linear-white-space> >>>>> > linear-white-space = 1*([CRLF] LWSP-char) >>>>> > LWSP-char = SP / HTAB >>>>> > quoted-pair = "\" CHAR >>>>> > phrase = 1*word >>>>> > route-addr = "<" [route] addr-spec ">" >>>>> > route = "@" domain ":" >>>>> > e164Number = "e164Number=" publicTypeOfNumber "," digits >>>>> > digits = 1*(DIGIT / "#" / "*" / ",") >>>>> > publicTypeOfNumber = "unknown" / "internationalStandard" / >>>>> > "nationalNumber" >>>>> > / "networkSpecificNumber" / "subscriberNumber" / >>>>> > / "abbreviatedNumber" >>>>> > dataPartyNumber = "dataPartyNumber=" digits >>>>> > telexPartyNumber= "telexPartyNumber=" digits >>>>> > privatePartyNumber = "privatePartyNumber=" >>>>> > privateTypeOfNumber "," digits >>>>> > privateTypeOfNumber = "unknown" / "level2RegionalNumber" / >>>>> > "level1RegionalNumber" >>>>> > / "pISNSpecificNumber" / "localNumber" / >>>>> > "abbreviatedNumber" >>>>> > TransportAddress = ipAddress / ipSourceRoute / ipxAddress / ip6Address >>>>> > / netBios / nsap / nonStandardAddress >>>>> > ipAddress = ip ":" port >>>>> > ip = 1*DIGIT "." 1*DIGIT "." 1*DIGIT "." 1*DIGIT >>>>> > port = 1*DIGIT >>>>> > ipSourceRoute = ip ":" port "," ip *1("," ip) ";" ("strict" >>>>> > / "loose") >>>>> > ipxAddress = 1*DIGIT ":" 1*DIGIT ":" 1*DIGIT >>>>> > ip6Address = 1*HEXDIGIT 14*(":" [1*HEXDIGIT]) 1*HEXDIGIT >>>>> > HEXDIGIT = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" >>>>> > netBios = ;; and so forth >>>>> > nsap = >>>>> > nonStandardAddress = >>>>> > >>>>> > Now, there may be an error or two in there, but at least it >>>>> > is more complete >>>>> > and an H.323 system knows how to work with these. (Note I >>>>> > did not address >>>>> > the new V4 alias "mobileIUM") >>>>> > >>>>> > If we used this grammar, I don't think we would need a lot of >>>>> > strange rules >>>>> > about what you do with the URL. Basically, you take it apart >>>>> > according to >>>>> > its internal parts to form an alias address that a Gatekeeper >>>>> > can resolve. >>>>> > >>>>> > Paul >>>>> > >>>>> > ----- Original Message ----- >>>>> > From: "Callaghan, Robert" <Robert.Callaghan(a)icn.siemens.com> >>>>> > To: "'Orit Levin'" <orit(a)radvision.com>; "'Paul E. Jones'" >>>>> > <paulej(a)PACKETIZER.COM> >>>>> > Cc: "Mailing list for parties associated with ITU-T Study >>>>> > Group 16 (E-mail)" >>>>> > <ITU-SG16(a)mailbag.cps.intel.com> >>>>> > Sent: Wednesday, June 14, 2000 3:50 PM >>>>> > Subject: RE: H.323 URL >>>>> > >>>>> > >>>>> > > Orit, >>>>> > > >>>>> > > In my opinion, an email-ID alias conforms to RFC-822 and is >>>>> > interpreted >>>>> > > according the rules stated in H.225.0. An H.323-URL-ID conforms to >>>>> > > TD-40a/Osaka and is interpreted according to the rules >>>>> > stated in TD-40a. >>>>> > An >>>>> > > H.323-ID is a character string without any rules of >>>>> > interpretation. I see >>>>> > > no need to blend these contexts. All three addressing >>>>> > modes can be use; >>>>> > > each in its own context. >>>>> > > >>>>> > > However, these are my opinion. Maybe more work is needed >>>>> > in Portland. >>>>> > > >>>>> > > Bob >>>>> > > >>>>> > > ------------------------------------------------------------------ >>>>> > > Robert Callaghan >>>>> > > Siemens Enterprise Networks >>>>> > > Tel: +1.561.923.1756 Fax: +1.561.923.1403 >>>>> > > Email: Robert.Callaghan(a)ICN.Siemens.com >>>>> > > ------------------------------------------------------------------ >>>>> > > >>>>> > > >>>>> > > -----Original Message----- >>>>> > > From: Orit Levin >>>>> [<mailto:orit@radvision.com>mailto:orit@radvision.com] >>>>> > > Sent: Wednesday, June 14, 2000 11:45 AM >>>>> > > To: Callaghan, Robert; 'Paul E. Jones' >>>>> > > Cc: Mailing list for parties associated with ITU-T Study Group 16 >>>>> > > (E-mail) >>>>> > > Subject: Re: H.323 URL >>>>> > > >>>>> > > >>>>> > > Hello Bob and Paul! >>>>> > > I don't see backwards compatibility problem, when the URL >>>>> > says explicitly >>>>> > > H323-URL. An appropriate change may be to state, that the >>>>> > default meaning >>>>> > of >>>>> > > url, encoded into email-ID alias, is according to RFC-822. >>>>> > > Now, I feel a need to put a chapter explaining what is the >>>>> > meaning of >>>>> > email >>>>> > > URL (apart from its syntax) when used in H.323 Network. >>>>> > There is some >>>>> > > explanation in H.225.0 Appendix IV. Do you find it clear >>>>> > and sufficient? >>>>> > > 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: Callaghan, Robert <Robert.Callaghan(a)icn.siemens.com> >>>>> > > To: 'Paul E. Jones' <paulej(a)PACKETIZER.COM>; 'Orit Levin' >>>>> > > <orit(a)radvision.com> >>>>> > > Cc: Mailing list for parties associated with ITU-T Study >>>>> > Group 16 (E-mail) >>>>> > > <ITU-SG16(a)mailbag.cps.intel.com> >>>>> > > Date: Wednesday, June 14, 2000 9:56 AM >>>>> > > Subject: H.323 URL >>>>> > > >>>>> > > >>>>> > > >Paul, >>>>> > > > >>>>> > > >I have a backward compatibility item for you to think about. >>>>> > > > >>>>> > > >TD-40/Osaka states that the H323-URL may be coded into the >>>>> > email-ID for >>>>> > > >alias address. However, H.225.0 states that the email-ID >>>>> > shall conform >>>>> > to >>>>> > > >RFC822. This is an exclusionary requirement in that other >>>>> > standards may >>>>> > > not >>>>> > > >be used. Also, Note 4 of the BNF definition of the >>>>> > H323-URL clearly >>>>> > states >>>>> > > >that that the H323-URL is *not* compatible with RFC822. >>>>> > > > >>>>> > > >Therefor, I propose that the H323-URL cannot be coded into >>>>> > the email-ID >>>>> > for >>>>> > > >alias address because of compatibility problems. >>>>> > > > >>>>> > > >Bob >>>>> > > > >>>>> > > >------------------------------------------------------------------ >>>>> > > >Robert Callaghan >>>>> > > >Siemens Enterprise Networks >>>>> > > >Tel: +1.561.923.1756 Fax: +1.561.923.1403 >>>>> > > >Email: Robert.Callaghan(a)ICN.Siemens.com >>>>> > > >------------------------------------------------------------------ >>>>> > > > >>>>> > > >>>>> > >>>>> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>>> > For help on this mail list, send "HELP ITU-SG16" in a message to >>>>> > listserv(a)mailbag.intel.com >>>>> > > > >------------------------------------------------------------------- >Chip Sharp CTO Consulting Engineering >Cisco Systems >Reality - Love it or Change it. >http://www.netaid.org >------------------------------------------------------------------- > >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >For help on this mail list, send "HELP ITU-SG16" in a message to >listserv(a)mailbag.intel.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

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Re: H.323 URL
by Callaghan, Robert 22 Jun '00

22 Jun '00

Orit, I am not now sure what was agreed to, other that to let TD-40a to move forward. I do agree with the three points in your note. I do not agree that the proposal was limited to Call Control Messages. I see no difference between the use of H.323-URLs on a Web page and the use of H.3233-URLs in Call Control. The one directly leads to the latter. I am not sure if you are implying that only H.323-URL can be used to direct a call to an H.323 destination. If so, I disagree. All alias formats work equally well. My understanding is that Paul Jones wanted the E.164 format of the H.323-URL in order to access the gateway using the H.323 client as a telephony client. This definitely does not point to an H.323 URL. I am afraid that we may not know what we agreed to, other than to proceed. That is why I objected that the URL be included in v4 instead of and annex or appendix. Now our lack of understanding as to what we understood will jeprodice v4 if it remains as is. But that was the agreement, so we must proceed forward. Bob -----Original Message----- From: Orit Levin [mailto:orit@radvision.com] Sent: Monday, June 19, 2000 10:06 AM To: ITU-SG16(a)mailbag.cps.intel.com Subject: Re: H.323 URL Dear all! There are two faces to H323-URL. The first one is when H.323-URL is used as an alias in H.323 Call Control messages. The second is when H.323-URL is used in Web pages or other hyperlinks. (Although, when both are in place, from procedural point of view their order is vice versa.) In my contribution in Osaka, I chose to address "the first case" first. There are number reasons for this: 1. URL concept exists in H.323 since version 2. The procedures, how URLs should be used, haven't been defined. This clearly invites interoperability problems. 2. H323-URL hasn't been defined at all. This leads to interpretation of other URLs, to be used INSTEAD, while reaching pure H.323 entities! This clearly invites interoperability problems. 3. Standard H323-URL can greatly facilitate address translation procedure, when H.323 runs on Internet. As it can be seen from TD-40a, it has been agreed, that H323-URL should be used to POINT TO H.323 DESTINATION. Other URLs may/should be used in H.323 messages to point to other destinations. Personally, I see this approach as the best. Also Bob and Francoise supported this in their last e-mails. Please, lets try not to open already agreed things before the next meeting, jeopardizing by that H.323v4 decision. Specifically on H323-URL topic, we have to clean things (such as the use of email ID alias) and put the basic version onto H.323v4. Then we will have "Annex O" to expand on additional "complimentary to H.323" procedures. One of these procedures is "the second face" of H323-URL: while used in WEB pages. It is clear that H.323-URL should be expanded with additional parameters to be used as such. It is also mentioned in TD-40a. Contributions are mostly welcome. 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 <http://www.radvision.com> orit(a)radvision.com <mailto:orit@radvision.com> -----Original Message----- From: Paul E. Jones < paulej(a)PACKETIZER.COM <mailto:paulej@PACKETIZER.COM> > To: ITU-SG16(a)MAILBAG.INTEL.COM <mailto:ITU-SG16@MAILBAG.INTEL.COM> < ITU-SG16(a)MAILBAG.INTEL.COM <mailto:ITU-SG16@MAILBAG.INTEL.COM> > Date: Monday, June 19, 2000 3:27 AM Subject: Re: H.323 URL Francois, If I want to provide a means of allowing somebody to call me by placing a URL on a web page, I need to provide something that can be resolved universally by H.323 endpoints. Bob mentioned querying a database-- that's certainly a possibility, assuming that that database contains all of the information it needs to resolve an address. What I am afraid of here is that we are introducing syntax to reach a resource without defining any procedure. If I see this url: h323:paulej@packetizer.com <mailto:h323:paulej@packetizer.com> What does that tell the H.323 entity? Is there a GK that is expecting a LRQ, AccessRequest, or is it something else entirely? Perhaps the right solution is to define (in normative text) the procedure for using SRV DNS records to query the packetizer.com domain. As Pete rightfully pointed out, an H.323 URL would be the perfect place to place conference identifiers for multipoint conferences: h323:conf-server1@packetizer.com;cid:XXXX-XXXX-XXXX-XXXX <mailto:h323:conf-server1@packetizer.com;cid:XXXX-XXXX-XXXX-XXXX> I think we need to work on the procedural part of this now. Who is working on that? 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: Friday, June 16, 2000 11:48 AM Subject: Re: H.323 URL I would agree with Bob here. Using an H.323 URL for a telephone number would imply that you can only be reached using H.323. Is this you intention? > -----Original Message----- > From: Callaghan, Robert [ mailto:Robert.Callaghan@ICN.SIEMENS.COM <mailto:Robert.Callaghan@ICN.SIEMENS.COM> ] > Sent: Friday, June 16, 2000 5:39 AM > To: ITU-SG16(a)MAILBAG.INTEL.COM <mailto:ITU-SG16@MAILBAG.INTEL.COM> > Subject: Re: H.323 URL > > > Paul, > > I think that this is getting complicated. > > I did not envision the use of the H.323-URL to encompase a > telephone number. > I only conceede for the purpose of progress. > > I saw the H.323-URL to be an identifier that would be used to access a > database. The DNS portion would identify the database, the > userID would be > the entry in the database. The database would then return > the necessary > information to complete the call. It is highly propable that this > information would include an E.164 or PNP address. This is > especially true > when the call must be ompleted over the SCN. > > I saw telephone numbers being defined in the "Tel:" URL > defined in RFC2806. > This URL covers many of optional fields needed to make an SCN > call which are > not presently covered in H.323. > > If we are to have multiple forms of an H.323 URL, I would > prefer to have > multi-URL IDs. > > Bob > > P.S. (By the way, the complex, cover everything, is where the > last try at an > H.323 URL diaappeared.) > > ------------------------------------------------------------------ > Robert Callaghan > Siemens Enterprise Networks > Tel: +1.561.923.1756 Fax: +1.561.923.1403 > Email: Robert.Callaghan(a)ICN.Siemens.com > ------------------------------------------------------------------ > > > -----Original Message----- > From: Paul E. Jones [ mailto:paulej@packetizer.com <mailto:paulej@packetizer.com> ] > Sent: Friday, June 16, 2000 3:11 AM > To: Callaghan, Robert; 'Orit Levin' > Cc: Mailing list for parties associated with ITU-T Study Group 16 > (E-mail) > Subject: Re: H.323 URL > > > Bob, > > I'm still surprised that you don't want to see the URL expanded... > especially to address party number types. Here is is currently: > > H323-URL = "H323:" user ["@" hostport] > user = username | phone-number > username = *( unreserved | escaped | "&" | "=" | "+" > | "$" | "," ) > hostport = host [ ":" port ] > host = hostname | IPv4address > hostname = *( domainlabel "." ) toplabel [ "." ] > domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum > toplabel = alpha | alpha *( alphanum | "-" ) alphanum > IPv4address = 1*digit "." 1*digit "." 1*digit "." 1*digit > port = *digit > reserved = ";" | "/" | "?" | ":" | "@" | "&" | "=" | > "+" |"$" | "," > digits = 1*DIGIT > > However, to be useful, information that follows the "h323:" should be > something in a form that an H.323 Gatekeeper can resolve. > Those things > include: > dialedDigits > h323-ID > email-ID > partyNumber > or one of the transportAddress types. > > This seems to be a reasonable syntax: > > H323-URL = "H323:" Address > Address = AliasAddress / TransportAddress > AliasAddress = dialedDigits / h323-ID / email-ID / partyNumber > dialedDigits = "dialedDigits=" 1*digit > h323-ID = "h323-ID=" 1*OCTET ; UTF-8 string represting the > BMPString > email-ID = "email-ID=" email-ID-spec > partyNumber = e164Number / dataPartyNumber / telexPartyNumber / > privateNumber > / nationalStandardPartyNumber > email-ID-spec = mailbox / group > group = phrase ":" [ mailbox ] ";" > phrase = 1*word > word = atom / quoted-string > atom = 1*CHAR ; any CHAR except specials, SPACE and CTLs > specials = "(" / ")" / "<" / ">" / "@" ; Must be in quoted- > / "," / ";" / ":" / "\" / <"> ; string, to use > / "." / "[" / "]" ; within a word. > quoted-string = > mailbox = addr-spec / phrase route-addr > addr-spec = local-part "@" domain > local-part = word *("." word) > domain = sub-domain *("." sub-domain) > sub-domain = domain-ref / domain-literal > domain-ref = atom > domain-literal = "[" *(dtext / quoted-pair) "]" > dtext = 1*CHAR ; Any CHAR excluding "[", "]", "\" & CR, > ; & including linear-white-space> > linear-white-space = 1*([CRLF] LWSP-char) > LWSP-char = SP / HTAB > quoted-pair = "\" CHAR > phrase = 1*word > route-addr = "<" [route] addr-spec ">" > route = "@" domain ":" > e164Number = "e164Number=" publicTypeOfNumber "," digits > digits = 1*(DIGIT / "#" / "*" / ",") > publicTypeOfNumber = "unknown" / "internationalStandard" / > "nationalNumber" > / "networkSpecificNumber" / "subscriberNumber" / > / "abbreviatedNumber" > dataPartyNumber = "dataPartyNumber=" digits > telexPartyNumber= "telexPartyNumber=" digits > privatePartyNumber = "privatePartyNumber=" > privateTypeOfNumber "," digits > privateTypeOfNumber = "unknown" / "level2RegionalNumber" / > "level1RegionalNumber" > / "pISNSpecificNumber" / "localNumber" / > "abbreviatedNumber" > TransportAddress = ipAddress / ipSourceRoute / ipxAddress / ip6Address > / netBios / nsap / nonStandardAddress > ipAddress = ip ":" port > ip = 1*DIGIT "." 1*DIGIT "." 1*DIGIT "." 1*DIGIT > port = 1*DIGIT > ipSourceRoute = ip ":" port "," ip *1("," ip) ";" ("strict" > / "loose") > ipxAddress = 1*DIGIT ":" 1*DIGIT ":" 1*DIGIT > ip6Address = 1*HEXDIGIT 14*(":" [1*HEXDIGIT]) 1*HEXDIGIT > HEXDIGIT = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" > netBios = ;; and so forth > nsap = > nonStandardAddress = > > Now, there may be an error or two in there, but at least it > is more complete > and an H.323 system knows how to work with these. (Note I > did not address > the new V4 alias "mobileIUM") > > If we used this grammar, I don't think we would need a lot of > strange rules > about what you do with the URL. Basically, you take it apart > according to > its internal parts to form an alias address that a Gatekeeper > can resolve. > > Paul > > ----- Original Message ----- > From: "Callaghan, Robert" <Robert.Callaghan(a)icn.siemens.com> > To: "'Orit Levin'" <orit(a)radvision.com>; "'Paul E. Jones'" > <paulej(a)PACKETIZER.COM> > Cc: "Mailing list for parties associated with ITU-T Study > Group 16 (E-mail)" > <ITU-SG16(a)mailbag.cps.intel.com> > Sent: Wednesday, June 14, 2000 3:50 PM > Subject: RE: H.323 URL > > > > Orit, > > > > In my opinion, an email-ID alias conforms to RFC-822 and is > interpreted > > according the rules stated in H.225.0. An H.323-URL-ID conforms to > > TD-40a/Osaka and is interpreted according to the rules > stated in TD-40a. > An > > H.323-ID is a character string without any rules of > interpretation. I see > > no need to blend these contexts. All three addressing > modes can be use; > > each in its own context. > > > > However, these are my opinion. Maybe more work is needed > in Portland. > > > > Bob > > > > ------------------------------------------------------------------ > > Robert Callaghan > > Siemens Enterprise Networks > > Tel: +1.561.923.1756 Fax: +1.561.923.1403 > > Email: Robert.Callaghan(a)ICN.Siemens.com > > ------------------------------------------------------------------ > > > > > > -----Original Message----- > > From: Orit Levin [ mailto:orit@radvision.com <mailto:orit@radvision.com> ] > > Sent: Wednesday, June 14, 2000 11:45 AM > > To: Callaghan, Robert; 'Paul E. Jones' > > Cc: Mailing list for parties associated with ITU-T Study Group 16 > > (E-mail) > > Subject: Re: H.323 URL > > > > > > Hello Bob and Paul! > > I don't see backwards compatibility problem, when the URL > says explicitly > > H323-URL. An appropriate change may be to state, that the > default meaning > of > > url, encoded into email-ID alias, is according to RFC-822. > > Now, I feel a need to put a chapter explaining what is the > meaning of > email > > URL (apart from its syntax) when used in H.323 Network. > There is some > > explanation in H.225.0 Appendix IV. Do you find it clear > and sufficient? > > 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: Callaghan, Robert <Robert.Callaghan(a)icn.siemens.com> > > To: 'Paul E. Jones' <paulej(a)PACKETIZER.COM>; 'Orit Levin' > > <orit(a)radvision.com> > > Cc: Mailing list for parties associated with ITU-T Study > Group 16 (E-mail) > > <ITU-SG16(a)mailbag.cps.intel.com> > > Date: Wednesday, June 14, 2000 9:56 AM > > Subject: H.323 URL > > > > > > >Paul, > > > > > >I have a backward compatibility item for you to think about. > > > > > >TD-40/Osaka states that the H323-URL may be coded into the > email-ID for > > >alias address. However, H.225.0 states that the email-ID > shall conform > to > > >RFC822. This is an exclusionary requirement in that other > standards may > > not > > >be used. Also, Note 4 of the BNF definition of the > H323-URL clearly > states > > >that that the H323-URL is *not* compatible with RFC822. > > > > > >Therefor, I propose that the H323-URL cannot be coded into > the email-ID > for > > >alias address because of compatibility problems. > > > > > >Bob > > > > > >------------------------------------------------------------------ > > >Robert Callaghan > > >Siemens Enterprise Networks > > >Tel: +1.561.923.1756 Fax: +1.561.923.1403 > > >Email: Robert.Callaghan(a)ICN.Siemens.com > > >------------------------------------------------------------------ > > > > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > For help on this mail list, send "HELP ITU-SG16" in a message to > listserv(a)mailbag.intel.com >

3 2

Re: TD-50/Osaka - Changes to the conferenceGoal field
by Callaghan, Robert 22 Jun '00

22 Jun '00

Pete, As you well know, for H.323 mandatory is in the eyes of the implementors. If an implementor does not think that they are useful for him then it won't be implemented. I think that Packages can be a useful service, but not mandatory. (I have yet to see a specific service to use Packages; but theoretically they are useful.) The problem is service that are mandatory, but have optional coding. Annex L has two coding formats in order to use v2 clients. I can seen some Packages services using the same technique - v4 uses Packages, v2 uses nonStandardControl. I would prefer a negotiation process like that for RAS negotiation - the originators asks for what is wanted, the response is what is available. Then the originators chooses what to do. If this is done, there is no need to mess with conferenceGoals. Bob ------------------------------------------------------------------ Robert Callaghan Siemens Enterprise Networks Tel: +1.561.923.1756 Fax: +1.561.923.1403 Email: Robert.Callaghan(a)ICN.Siemens.com ------------------------------------------------------------------ -----Original Message----- From: Pete Cordell [mailto:pete@TECH-KNOW-WARE.COM] Sent: Tuesday, June 20, 2000 2:01 PM To: ITU-SG16(a)mailbag.cps.intel.com Subject: Re: TD-50/Osaka - Changes to the conferenceGoal field Bob, You have made the perfect argument for leaving neededFeatures in the conferenceGoal! Previously we could say that support for packages was optional because we were relying on the conferenceGoal backwards compatibility method to work for V4 endpoints. This is because all the support packages need is to reject a call if neededFeatures is signalled. If we have to move neededFeatures to some other position, then packages MUST become MANDATORY, at least in terms of recognising that neededFeatures are present. I would imagine that you wouldn't like this. Pete. P.S. I believe you have expressed some concern that calls should be able to continue even if certain features are not supported which may be causing you to be worried about packages. This can be easily achieved with packages. Simply DON'T signal the features that you desire as neededFeatures, signal them as desiredFeatures. You then have the behaviour that you are looking for. The important thing here is that it gives the network architect the choice of the behaviour that should happen. Or should Siemens customers take what they're given and lump it :) ============================================= Pete Cordell Tech-Know-Ware pete(a)tech-know-ware.com +44 1473 635863 ============================================= ----- Original Message ----- From: Callaghan, Robert <Robert.Callaghan(a)ICN.SIEMENS.COM> To: <ITU-SG16(a)mailbag.cps.intel.com> Sent: 20 June 2000 14:53 Subject: Re: TD-50/Osaka - Changes to the conferenceGoal field > Rich, > > I agree that a v4 client that supports packages and further supports a > specific feature will respond. My comment is in regard to the generation of > a negative message indicating that the feature is not support. If a v4 > client supports packages but not a feature, it will resond with a negative > message. However if the v4 client does not support packages, it will not > respond at all. This is worse that the v2 or v3 clients if the change in > conferceGoals is made. Therefor, my idea is that the change in > conferenceGoal is not needed because than the v2, v3, and some v4 clients > will work the same. This allows the addition of coding of package > information to be anywhere other than conferenceGoal. > > Bob > > -----Original Message----- > From: Rich Bowen [mailto:rkbowen@cisco.com] > Sent: Tuesday, June 20, 2000 3:20 AM > To: Callaghan, Robert > Cc: 'Mailing list for parties associated with ITU-T Study Group 16' > Subject: Re: TD-50/Osaka - Changes to the conferenceGoal field > > > > Bob, > > If the v4 client supports the features listed in the needFeatures field, > then it will respond with those same features listed in a > supportedFeatures field, as an acknowledgement. Presumably if it > acknowledges features in this way, then it will not ignore packages > related to those features. > > Rich > > "Callaghan, Robert" wrote: > > > > Rich, > > > > I question that the concept for forcing conferenceGoal to fail will even > > work. > > > > The use of conferenceGoal will detect a v2 or v3 client through a failure. > > But the version number will also detect the older versions. A v4 client > can > > properly detect and decode the new structure. However, support of > packages > > is optional, so the client can ignore the requirement to evaluate the > > packages. > > > > Then what? > > > > Bob > > > > -----Original Message----- > > From: Rich Bowen [mailto:rkbowen@CISCO.COM] > > Sent: Sunday, June 18, 2000 5:14 PM > > To: ITU-SG16(a)mailbag.cps.intel.com > > Subject: TD-50/Osaka - Changes to the conferenceGoal field > > > > All, > > > > In Osaka we agreed to add support for packages to H.225.0 along the > > lines of TD-50 (ftp://standard.pictel.com/avc-site/0005_Osa/TD-50.zip). > > There was some concern raised about the proposed modifications to the > > conferenceGoal field in the Setup message. The meeting report states: > > > > "Some issues were raised about conflicts in the usage of the conference > > goal field between this new method and H.450.x. A possible solution is > > to create a new field in the ASN.1 to avoid conflicts. The editors are > > empowered to work with interested parties to resolve these conflicts in > > the ASN.1 before the white paper is issued." > > > > The modification proposed in TD-50 was the addition of the > > "neededFeatures" field to the confereceGoal field of the Setup-UUIE: > > > > conferenceGoal CHOICE > > { > > create NULL, > > join NULL, > > invite NULL, > > ..., > > capability-negotiation NULL, > > callIndependentSupplementaryService NULL, > > --> neededFeatures NeededFeatureGoal > > }, > > > > where the NeededFeatureGoal structure is defined as: > > > > NeededFeatureGoal ::= SEQUENCE > > { > > basicGoal CHOICE > > { > > create NULL, > > join NULL, > > invite NULL, > > capability-negotiation NULL, > > callIndependentSupplementaryService NULL, > > ... > > } OPTIONAL, > > features SEQUENCE OF SupportedFeatures, > > ... > > } > > > > An alternative approach would be to add a neededFeatures field at the > > highest level of the Setup-UUIE ASN.1 instead of inside the > > conferenceGoal structure, similar to the way the desirededFeatures and > > supportedFeatures fields will be added (see TD-50), like this: > > > > Setup-UUIE ::= SEQUENCE > > { > > [snip] > > --> neededFeatures SEQUENCE OF SupportedFeatures OPTIONAL, > > desiredFeatures SEQUENCE OF SupportedFeatures OPTIONAL, > > supportedFeatures SEQUENCE OF SupportedFeatures OPTIONAL > > } > > > > The motivation for adding neededFeatures to the conferenceGoal field was > > to force a call failure when trying to setup a call to pre-v4 endpoint > > and there is some v4 or later feature that is *required* for the call. > > The mechanism is intended to work like this: > > > > o The v4 EP sends Setup to the pre-v4 endpoint, and specifies some > > required feature in the neededFeatures field of the conferenceGoal. > > o The pre-v4 EP doesn't recognize the neededFeatures field as a > > supported CHOICE for a conferenceGoal, so it sends Release Complete. > > > > There would not be any conflicts with H.450, as suggested in the meeting > > report, because if the callIndependentSupplementaryService was needed, > > it would still be specified. The difference is that, if a neededFeature > > was also required, the H.450 goals would be specified inside the > > NeededFeatureGoal structure, which v4 and later endpoints would be aware > > of. > > > > These are the pros and cons of adding neededFeatures to the > > conferenceGoal vs. adding it to Setup-UUIE, IMO: > > o Advantages: > > - *May* force an early call release if a required feature is > > not supported by a pre-v4 endpoint. > > o Disadvantages: > > - ASN.1 and thus implementation would be more complex. > > Potentially have to check the conferenceGoal in two structures > > instead of one. > > - If pre-v4 EP sends Release Complete, there is no way to > > know whether it was sent because of an unrecognized > > conferenceGoal, because there is no ReleaseCompleteReason > > defined for that purpose. > > - H.323 does not require failing a call if the conferenceGoal > > is unrecognized, so the mechanism may not work at all. > > > > Although I think this mechanism is a good idea (and I supported it in > > Osaka), at this point I don't think it would work reliably enough to > > justify the added complexity. So I would prefer the alternative > > approach described above, adding the neededFeatures field directly to > > the Setup-UUIE. > > > > Okay, fire away. :-) > > > > Regards, > > Rich > > -------------------------------------------------------------------- > > Richard K. Bowen Cisco Systems, Inc. > > VoIP Session Protocols Research Triangle Park, NC, USA > > -------------------------------------------------------------------- > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > For help on this mail list, send "HELP ITU-SG16" in a message to > > listserv(a)mailbag.intel.com > > -- > -------------------------------------------------------------------- > Richard K. Bowen Cisco Systems, Inc. > VoIP Session Protocols Research Triangle Park, NC, USA > -------------------------------------------------------------------- > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > For help on this mail list, send "HELP ITU-SG16" in a message to > listserv(a)mailbag.intel.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

3 6

next revision of H.323 Annex H ?
by Kumar, Vineet 21 Jun '00

21 Jun '00

Jaakko, When is the next revision of H.323 Annex H draft scheduled to be out ? Regards, vineet ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

1 0

[robustness]Comments on TD-42/Osaka
by Rich Bowen 21 Jun '00

21 Jun '00

Robustness folks, A couple of comments on TD-42/Osaka - 1) While adding the ASN.1 from TD-42 to the draft H.225.0 v4, I noticed the following paragraph about using StatusInquiry as a keepalive mechanism: "The element closer to the called party shall send StatusInquiry periodically (this is the direction of least traffic during established calls). The period should be configurable. Two seconds is the recommended default, in order to allow detection of failure before other messages timeout. The selected value must be added to StatusInquiry so that the recipient can also monitor failure without an additional StatusInquiry/Status exchange in the opposite direction. The recipient system needs only to maintain a timer using the indicated value as a timeout." This clause indicates that the period at which StatusInquiry is sent is also the amount of time that the receiving system should use as a timeToLive timer. This arrangement would result in a race condition since the next StatusInquiry would be expected at the exact moment that the timeToLive timer was due to expire. IMHO, the StatusInquiry period and the timeToLive should be separately configurable, both having default values defined in Annex R, with the obvious restriction that timeToLive shall be greater than the StatusInquiry period. 2) Has consideration been given to adding the ability for the endpoint to indicate to the GK via the ARQ that a particular call requires robustness, or to allowing the GK to indicate to the EP that the EP must use the robustness procedure for a particular call? Several other features added in v4 use this model and it seems to be a useful framework. - Rich ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

2 4

[Fwd: Final Corrections to H.225.0v3]
by Rich Bowen 21 Jun '00

21 Jun '00

All, Paul Jones is having trouble with email access from home, where he does his standards work, and asked me if I could resend the attached email that he sent earlier. A couple of people have told him they did not see this on the itu-sg16 list. Rich -------------------------------------------------------------------- Richard K. Bowen Cisco Systems, Inc. VoIP Session Protocols Research Triangle Park, NC, USA --------------------------------------------------------------------

1 0

Re: TD-50/Osaka - Changes to the conferenceGoal field
by Callaghan, Robert 20 Jun '00

20 Jun '00

Rich, I agree that a v4 client that supports packages and further supports a specific feature will respond. My comment is in regard to the generation of a negative message indicating that the feature is not support. If a v4 client supports packages but not a feature, it will resond with a negative message. However if the v4 client does not support packages, it will not respond at all. This is worse that the v2 or v3 clients if the change in conferceGoals is made. Therefor, my idea is that the change in conferenceGoal is not needed because than the v2, v3, and some v4 clients will work the same. This allows the addition of coding of package information to be anywhere other than conferenceGoal. Bob -----Original Message----- From: Rich Bowen [mailto:rkbowen@cisco.com] Sent: Tuesday, June 20, 2000 3:20 AM To: Callaghan, Robert Cc: 'Mailing list for parties associated with ITU-T Study Group 16' Subject: Re: TD-50/Osaka - Changes to the conferenceGoal field Bob, If the v4 client supports the features listed in the needFeatures field, then it will respond with those same features listed in a supportedFeatures field, as an acknowledgement. Presumably if it acknowledges features in this way, then it will not ignore packages related to those features. Rich "Callaghan, Robert" wrote: > > Rich, > > I question that the concept for forcing conferenceGoal to fail will even > work. > > The use of conferenceGoal will detect a v2 or v3 client through a failure. > But the version number will also detect the older versions. A v4 client can > properly detect and decode the new structure. However, support of packages > is optional, so the client can ignore the requirement to evaluate the > packages. > > Then what? > > Bob > > -----Original Message----- > From: Rich Bowen [mailto:rkbowen@CISCO.COM] > Sent: Sunday, June 18, 2000 5:14 PM > To: ITU-SG16(a)mailbag.cps.intel.com > Subject: TD-50/Osaka - Changes to the conferenceGoal field > > All, > > In Osaka we agreed to add support for packages to H.225.0 along the > lines of TD-50 (ftp://standard.pictel.com/avc-site/0005_Osa/TD-50.zip). > There was some concern raised about the proposed modifications to the > conferenceGoal field in the Setup message. The meeting report states: > > "Some issues were raised about conflicts in the usage of the conference > goal field between this new method and H.450.x. A possible solution is > to create a new field in the ASN.1 to avoid conflicts. The editors are > empowered to work with interested parties to resolve these conflicts in > the ASN.1 before the white paper is issued." > > The modification proposed in TD-50 was the addition of the > "neededFeatures" field to the confereceGoal field of the Setup-UUIE: > > conferenceGoal CHOICE > { > create NULL, > join NULL, > invite NULL, > ..., > capability-negotiation NULL, > callIndependentSupplementaryService NULL, > --> neededFeatures NeededFeatureGoal > }, > > where the NeededFeatureGoal structure is defined as: > > NeededFeatureGoal ::= SEQUENCE > { > basicGoal CHOICE > { > create NULL, > join NULL, > invite NULL, > capability-negotiation NULL, > callIndependentSupplementaryService NULL, > ... > } OPTIONAL, > features SEQUENCE OF SupportedFeatures, > ... > } > > An alternative approach would be to add a neededFeatures field at the > highest level of the Setup-UUIE ASN.1 instead of inside the > conferenceGoal structure, similar to the way the desirededFeatures and > supportedFeatures fields will be added (see TD-50), like this: > > Setup-UUIE ::= SEQUENCE > { > [snip] > --> neededFeatures SEQUENCE OF SupportedFeatures OPTIONAL, > desiredFeatures SEQUENCE OF SupportedFeatures OPTIONAL, > supportedFeatures SEQUENCE OF SupportedFeatures OPTIONAL > } > > The motivation for adding neededFeatures to the conferenceGoal field was > to force a call failure when trying to setup a call to pre-v4 endpoint > and there is some v4 or later feature that is *required* for the call. > The mechanism is intended to work like this: > > o The v4 EP sends Setup to the pre-v4 endpoint, and specifies some > required feature in the neededFeatures field of the conferenceGoal. > o The pre-v4 EP doesn't recognize the neededFeatures field as a > supported CHOICE for a conferenceGoal, so it sends Release Complete. > > There would not be any conflicts with H.450, as suggested in the meeting > report, because if the callIndependentSupplementaryService was needed, > it would still be specified. The difference is that, if a neededFeature > was also required, the H.450 goals would be specified inside the > NeededFeatureGoal structure, which v4 and later endpoints would be aware > of. > > These are the pros and cons of adding neededFeatures to the > conferenceGoal vs. adding it to Setup-UUIE, IMO: > o Advantages: > - *May* force an early call release if a required feature is > not supported by a pre-v4 endpoint. > o Disadvantages: > - ASN.1 and thus implementation would be more complex. > Potentially have to check the conferenceGoal in two structures > instead of one. > - If pre-v4 EP sends Release Complete, there is no way to > know whether it was sent because of an unrecognized > conferenceGoal, because there is no ReleaseCompleteReason > defined for that purpose. > - H.323 does not require failing a call if the conferenceGoal > is unrecognized, so the mechanism may not work at all. > > Although I think this mechanism is a good idea (and I supported it in > Osaka), at this point I don't think it would work reliably enough to > justify the added complexity. So I would prefer the alternative > approach described above, adding the neededFeatures field directly to > the Setup-UUIE. > > Okay, fire away. :-) > > Regards, > Rich > -------------------------------------------------------------------- > Richard K. Bowen Cisco Systems, Inc. > VoIP Session Protocols Research Triangle Park, NC, USA > -------------------------------------------------------------------- > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > For help on this mail list, send "HELP ITU-SG16" in a message to > listserv(a)mailbag.intel.com -- -------------------------------------------------------------------- Richard K. Bowen Cisco Systems, Inc. VoIP Session Protocols Research Triangle Park, NC, USA -------------------------------------------------------------------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

2 1

Re: H.323 URL
by Orit Levin 20 Jun '00

20 Jun '00

RE: H.323 URLBob, sorry for being unclear. This is why face-to-face discussions are, after all, more efficient. I agree with all (?) your points. What I wanted to say is, that H323-URL, in its current format, provides sufficient means for - originator's local application to activate H.323 application, while configured consistently within its zone policies - zone's server (most probably a GK.) to invoke DNS based address resolution procedure, based on the received H323-URL The current H323-URL definition and the proposed text are NOT sufficient (but BOTH are expandable) to provide more functionality to that, we have today, such as: - meaning of non-H323 URLs in H.323 messages and the corresponding procedures - H323-URL used in WEB pages when extensive configuration means are not available and/or not sufficient Now, to Chip's remarks. It seems to me helpful to add this kind of "url tutorial" to Annex O. After all, what may be seen obvious to the authors, is not necessarily obvious to the readers/implementers of H.323. Chip, I have a question to you. I send a request to IANA, as to the procedures to add the new H323-URL identifier. No answer so far. Any help/guidance would be appreciated. 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: Callaghan, Robert <Robert.Callaghan(a)ICN.SIEMENS.COM> To: ITU-SG16(a)MAILBAG.INTEL.COM <ITU-SG16(a)MAILBAG.INTEL.COM> Date: Monday, June 19, 2000 2:51 PM Subject: Re: H.323 URL Orit, I am not now sure what was agreed to, other that to let TD-40a to move forward. I do agree with the three points in your note. I do not agree that the proposal was limited to Call Control Messages. I see no difference between the use of H.323-URLs on a Web page and the use of H.3233-URLs in Call Control. The one directly leads to the latter. I am not sure if you are implying that only H.323-URL can be used to direct a call to an H.323 destination. If so, I disagree. All alias formats work equally well. My understanding is that Paul Jones wanted the E.164 format of the H.323-URL in order to access the gateway using the H.323 client as a telephony client. This definitely does not point to an H.323 URL. I am afraid that we may not know what we agreed to, other than to proceed. That is why I objected that the URL be included in v4 instead of and annex or appendix. Now our lack of understanding as to what we understood will jeprodice v4 if it remains as is. But that was the agreement, so we must proceed forward. Bob -----Original Message----- From: Orit Levin [mailto:orit@radvision.com] Sent: Monday, June 19, 2000 10:06 AM To: ITU-SG16(a)mailbag.cps.intel.com Subject: Re: H.323 URL Dear all! There are two faces to H323-URL. The first one is when H.323-URL is used as an alias in H.323 Call Control messages. The second is when H.323-URL is used in Web pages or other hyperlinks. (Although, when both are in place, from procedural point of view their order is vice versa.) In my contribution in Osaka, I chose to address "the first case" first. There are number reasons for this: 1. URL concept exists in H.323 since version 2. The procedures, how URLs should be used, haven't been defined. This clearly invites interoperability problems. 2. H323-URL hasn't been defined at all. This leads to interpretation of other URLs, to be used INSTEAD, while reaching pure H.323 entities! This clearly invites interoperability problems. 3. Standard H323-URL can greatly facilitate address translation procedure, when H.323 runs on Internet. As it can be seen from TD-40a, it has been agreed, that H323-URL should be used to POINT TO H.323 DESTINATION. Other URLs may/should be used in H.323 messages to point to other destinations. Personally, I see this approach as the best. Also Bob and Francoise supported this in their last e-mails. Please, lets try not to open already agreed things before the next meeting, jeopardizing by that H.323v4 decision. Specifically on H323-URL topic, we have to clean things (such as the use of email ID alias) and put the basic version onto H.323v4. Then we will have "Annex O" to expand on additional "complimentary to H.323" procedures. One of these procedures is "the second face" of H323-URL: while used in WEB pages. It is clear that H.323-URL should be expanded with additional parameters to be used as such. It is also mentioned in TD-40a. Contributions are mostly welcome. 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: Paul E. Jones <paulej(a)PACKETIZER.COM> To: ITU-SG16(a)MAILBAG.INTEL.COM <ITU-SG16(a)MAILBAG.INTEL.COM> Date: Monday, June 19, 2000 3:27 AM Subject: Re: H.323 URL Francois, If I want to provide a means of allowing somebody to call me by placing a URL on a web page, I need to provide something that can be resolved universally by H.323 endpoints. Bob mentioned querying a database-- that's certainly a possibility, assuming that that database contains all of the information it needs to resolve an address. What I am afraid of here is that we are introducing syntax to reach a resource without defining any procedure. If I see this url: h323:paulej@packetizer.com What does that tell the H.323 entity? Is there a GK that is expecting a LRQ, AccessRequest, or is it something else entirely? Perhaps the right solution is to define (in normative text) the procedure for using SRV DNS records to query the packetizer.com domain. As Pete rightfully pointed out, an H.323 URL would be the perfect place to place conference identifiers for multipoint conferences: h323:conf-server1@packetizer.com;cid:XXXX-XXXX-XXXX-XXXX I think we need to work on the procedural part of this now. Who is working on that? Paul ----- Original Message ----- From: Francois Audet To: ITU-SG16(a)mailbag.cps.intel.com Sent: Friday, June 16, 2000 11:48 AM Subject: Re: H.323 URL I would agree with Bob here. Using an H.323 URL for a telephone number would imply that you can only be reached using H.323. Is this you intention? > -----Original Message----- > From: Callaghan, Robert [mailto:Robert.Callaghan@ICN.SIEMENS.COM] > Sent: Friday, June 16, 2000 5:39 AM > To: ITU-SG16(a)MAILBAG.INTEL.COM > Subject: Re: H.323 URL > > > Paul, > > I think that this is getting complicated. > > I did not envision the use of the H.323-URL to encompase a > telephone number. > I only conceede for the purpose of progress. > > I saw the H.323-URL to be an identifier that would be used to access a > database. The DNS portion would identify the database, the > userID would be > the entry in the database. The database would then return > the necessary > information to complete the call. It is highly propable that this > information would include an E.164 or PNP address. This is > especially true > when the call must be ompleted over the SCN. > > I saw telephone numbers being defined in the "Tel:" URL > defined in RFC2806. > This URL covers many of optional fields needed to make an SCN > call which are > not presently covered in H.323. > > If we are to have multiple forms of an H.323 URL, I would > prefer to have > multi-URL IDs. > > Bob > > P.S. (By the way, the complex, cover everything, is where the > last try at an > H.323 URL diaappeared.) > > ------------------------------------------------------------------ > Robert Callaghan > Siemens Enterprise Networks > Tel: +1.561.923.1756 Fax: +1.561.923.1403 > Email: Robert.Callaghan(a)ICN.Siemens.com > ------------------------------------------------------------------ > > > -----Original Message----- > From: Paul E. Jones [mailto:paulej@packetizer.com] > Sent: Friday, June 16, 2000 3:11 AM > To: Callaghan, Robert; 'Orit Levin' > Cc: Mailing list for parties associated with ITU-T Study Group 16 > (E-mail) > Subject: Re: H.323 URL > > > Bob, > > I'm still surprised that you don't want to see the URL expanded... > especially to address party number types. Here is is currently: > > H323-URL = "H323:" user ["@" hostport] > user = username | phone-number > username = *( unreserved | escaped | "&" | "=" | "+" > | "$" | "," ) > hostport = host [ ":" port ] > host = hostname | IPv4address > hostname = *( domainlabel "." ) toplabel [ "." ] > domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum > toplabel = alpha | alpha *( alphanum | "-" ) alphanum > IPv4address = 1*digit "." 1*digit "." 1*digit "." 1*digit > port = *digit > reserved = ";" | "/" | "?" | ":" | "@" | "&" | "=" | > "+" |"$" | "," > digits = 1*DIGIT > > However, to be useful, information that follows the "h323:" should be > something in a form that an H.323 Gatekeeper can resolve. > Those things > include: > dialedDigits > h323-ID > email-ID > partyNumber > or one of the transportAddress types. > > This seems to be a reasonable syntax: > > H323-URL = "H323:" Address > Address = AliasAddress / TransportAddress > AliasAddress = dialedDigits / h323-ID / email-ID / partyNumber > dialedDigits = "dialedDigits=" 1*digit > h323-ID = "h323-ID=" 1*OCTET ; UTF-8 string represting the > BMPString > email-ID = "email-ID=" email-ID-spec > partyNumber = e164Number / dataPartyNumber / telexPartyNumber / > privateNumber > / nationalStandardPartyNumber > email-ID-spec = mailbox / group > group = phrase ":" [ mailbox ] ";" > phrase = 1*word > word = atom / quoted-string > atom = 1*CHAR ; any CHAR except specials, SPACE and CTLs > specials = "(" / ")" / "<" / ">" / "@" ; Must be in quoted- > / "," / ";" / ":" / "\" / <"> ; string, to use > / "." / "[" / "]" ; within a word. > quoted-string = > mailbox = addr-spec / phrase route-addr > addr-spec = local-part "@" domain > local-part = word *("." word) > domain = sub-domain *("." sub-domain) > sub-domain = domain-ref / domain-literal > domain-ref = atom > domain-literal = "[" *(dtext / quoted-pair) "]" > dtext = 1*CHAR ; Any CHAR excluding "[", "]", "\" & CR, > ; & including linear-white-space> > linear-white-space = 1*([CRLF] LWSP-char) > LWSP-char = SP / HTAB > quoted-pair = "\" CHAR > phrase = 1*word > route-addr = "<" [route] addr-spec ">" > route = "@" domain ":" > e164Number = "e164Number=" publicTypeOfNumber "," digits > digits = 1*(DIGIT / "#" / "*" / ",") > publicTypeOfNumber = "unknown" / "internationalStandard" / > "nationalNumber" > / "networkSpecificNumber" / "subscriberNumber" / > / "abbreviatedNumber" > dataPartyNumber = "dataPartyNumber=" digits > telexPartyNumber= "telexPartyNumber=" digits > privatePartyNumber = "privatePartyNumber=" > privateTypeOfNumber "," digits > privateTypeOfNumber = "unknown" / "level2RegionalNumber" / > "level1RegionalNumber" > / "pISNSpecificNumber" / "localNumber" / > "abbreviatedNumber" > TransportAddress = ipAddress / ipSourceRoute / ipxAddress / ip6Address > / netBios / nsap / nonStandardAddress > ipAddress = ip ":" port > ip = 1*DIGIT "." 1*DIGIT "." 1*DIGIT "." 1*DIGIT > port = 1*DIGIT > ipSourceRoute = ip ":" port "," ip *1("," ip) ";" ("strict" > / "loose") > ipxAddress = 1*DIGIT ":" 1*DIGIT ":" 1*DIGIT > ip6Address = 1*HEXDIGIT 14*(":" [1*HEXDIGIT]) 1*HEXDIGIT > HEXDIGIT = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" > netBios = ;; and so forth > nsap = > nonStandardAddress = > > Now, there may be an error or two in there, but at least it > is more complete > and an H.323 system knows how to work with these. (Note I > did not address > the new V4 alias "mobileIUM") > > If we used this grammar, I don't think we would need a lot of > strange rules > about what you do with the URL. Basically, you take it apart > according to > its internal parts to form an alias address that a Gatekeeper > can resolve. > > Paul > > ----- Original Message ----- > From: "Callaghan, Robert" <Robert.Callaghan(a)icn.siemens.com> > To: "'Orit Levin'" <orit(a)radvision.com>; "'Paul E. Jones'" > <paulej(a)PACKETIZER.COM> > Cc: "Mailing list for parties associated with ITU-T Study > Group 16 (E-mail)" > <ITU-SG16(a)mailbag.cps.intel.com> > Sent: Wednesday, June 14, 2000 3:50 PM > Subject: RE: H.323 URL > > > > Orit, > > > > In my opinion, an email-ID alias conforms to RFC-822 and is > interpreted > > according the rules stated in H.225.0. An H.323-URL-ID conforms to > > TD-40a/Osaka and is interpreted according to the rules > stated in TD-40a. > An > > H.323-ID is a character string without any rules of > interpretation. I see > > no need to blend these contexts. All three addressing > modes can be use; > > each in its own context. > > > > However, these are my opinion. Maybe more work is needed > in Portland. > > > > Bob > > > > ------------------------------------------------------------------ > > Robert Callaghan > > Siemens Enterprise Networks > > Tel: +1.561.923.1756 Fax: +1.561.923.1403 > > Email: Robert.Callaghan(a)ICN.Siemens.com > > ------------------------------------------------------------------ > > > > > > -----Original Message----- > > From: Orit Levin [mailto:orit@radvision.com] > > Sent: Wednesday, June 14, 2000 11:45 AM > > To: Callaghan, Robert; 'Paul E. Jones' > > Cc: Mailing list for parties associated with ITU-T Study Group 16 > > (E-mail) > > Subject: Re: H.323 URL > > > > > > Hello Bob and Paul! > > I don't see backwards compatibility problem, when the URL > says explicitly > > H323-URL. An appropriate change may be to state, that the > default meaning > of > > url, encoded into email-ID alias, is according to RFC-822. > > Now, I feel a need to put a chapter explaining what is the > meaning of > email > > URL (apart from its syntax) when used in H.323 Network. > There is some > > explanation in H.225.0 Appendix IV. Do you find it clear > and sufficient? > > 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: Callaghan, Robert <Robert.Callaghan(a)icn.siemens.com> > > To: 'Paul E. Jones' <paulej(a)PACKETIZER.COM>; 'Orit Levin' > > <orit(a)radvision.com> > > Cc: Mailing list for parties associated with ITU-T Study > Group 16 (E-mail) > > <ITU-SG16(a)mailbag.cps.intel.com> > > Date: Wednesday, June 14, 2000 9:56 AM > > Subject: H.323 URL > > > > > > >Paul, > > > > > >I have a backward compatibility item for you to think about. > > > > > >TD-40/Osaka states that the H323-URL may be coded into the > email-ID for > > >alias address. However, H.225.0 states that the email-ID > shall conform > to > > >RFC822. This is an exclusionary requirement in that other > standards may > > not > > >be used. Also, Note 4 of the BNF definition of the > H323-URL clearly > states > > >that that the H323-URL is *not* compatible with RFC822. > > > > > >Therefor, I propose that the H323-URL cannot be coded into > the email-ID > for > > >alias address because of compatibility problems. > > > > > >Bob > > > > > >------------------------------------------------------------------ > > >Robert Callaghan > > >Siemens Enterprise Networks > > >Tel: +1.561.923.1756 Fax: +1.561.923.1403 > > >Email: Robert.Callaghan(a)ICN.Siemens.com > > >------------------------------------------------------------------ > > > > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > For help on this mail list, send "HELP ITU-SG16" in a message to > listserv(a)mailbag.intel.com >

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static vs dynamic configuration
by Agboh, Charles 20 Jun '00

20 Jun '00

I am not sure if this is the place to ask this question but I would like some comments on the following. in a static configuration I have H.323 gateways deployed with no gatekeeper in a dynamic configuration I have the static configuation with a gatekeeper. What are the advantages of the dynamic configuration over the static configuration. regards, charles ---------------------------- Charles Keli Agboh Data and Access R&D - GTS Network Services Terhulpsesteenweg 6A 1560 Hoeilaart (Brussels) Belgium Direct: +32 2 658 4243 Mobile: +32 479 28 97 35 Fax: +32 2 700 43 66 Email: charles.agboh(a)gtsgroup.com http://www.gtsgroup.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

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AW: TD-50/Osaka - Changes to the conferenceGoal field
by Klaghofer Karl ICN EN HC SE 81 20 Jun '00

20 Jun '00

H.323 procedures and H.450.1 procedures reference H.225.0 on how to set the conferenceGoal for certain cases (e.g. for conference invitations, 450 call independent signalling connections, ...). So far there is exactly one field to be used for setting the appropriate value. With the original BT proposal, we would suddenly in v4 have two ways on how to set the conferenceGoal (depending on whether I send the new v4 optional neededFeatures package or not). Again, we should go with the alternative proposal provided by Rich keeping the optional neededFeatures package out of the conferenceGoal construct. It does not belong there. The guideline has always been that new optional features shall not impact existing behaviour. Karl Klaghofer Siemens karl.klaghofer(a)icn.siemens.de > -----Ursprüngliche Nachricht----- > Von: Rich Bowen [SMTP:rkbowen@CISCO.COM] > Gesendet am: Tuesday, June 20, 2000 09:20 > An: ITU-SG16(a)mailbag.cps.intel.com > Betreff: Re: TD-50/Osaka - Changes to the conferenceGoal field > > Bob, > > If the v4 client supports the features listed in the needFeatures field, > then it will respond with those same features listed in a > supportedFeatures field, as an acknowledgement. Presumably if it > acknowledges features in this way, then it will not ignore packages > related to those features. > > Rich > > "Callaghan, Robert" wrote: > > > > Rich, > > > > I question that the concept for forcing conferenceGoal to fail will even > > work. > > > > The use of conferenceGoal will detect a v2 or v3 client through a > failure. > > But the version number will also detect the older versions. A v4 client > can > > properly detect and decode the new structure. However, support of > packages > > is optional, so the client can ignore the requirement to evaluate the > > packages. > > > > Then what? > > > > Bob > > > > -----Original Message----- > > From: Rich Bowen [mailto:rkbowen@CISCO.COM] > > Sent: Sunday, June 18, 2000 5:14 PM > > To: ITU-SG16(a)mailbag.cps.intel.com > > Subject: TD-50/Osaka - Changes to the conferenceGoal field > > > > All, > > > > In Osaka we agreed to add support for packages to H.225.0 along the > > lines of TD-50 (ftp://standard.pictel.com/avc-site/0005_Osa/TD-50.zip). > > There was some concern raised about the proposed modifications to the > > conferenceGoal field in the Setup message. The meeting report states: > > > > "Some issues were raised about conflicts in the usage of the conference > > goal field between this new method and H.450.x. A possible solution is > > to create a new field in the ASN.1 to avoid conflicts. The editors are > > empowered to work with interested parties to resolve these conflicts in > > the ASN.1 before the white paper is issued." > > > > The modification proposed in TD-50 was the addition of the > > "neededFeatures" field to the confereceGoal field of the Setup-UUIE: > > > > conferenceGoal CHOICE > > { > > create NULL, > > join NULL, > > invite NULL, > > ..., > > capability-negotiation NULL, > > callIndependentSupplementaryService NULL, > > --> neededFeatures NeededFeatureGoal > > }, > > > > where the NeededFeatureGoal structure is defined as: > > > > NeededFeatureGoal ::= SEQUENCE > > { > > basicGoal CHOICE > > { > > create NULL, > > join NULL, > > invite NULL, > > capability-negotiation NULL, > > callIndependentSupplementaryService NULL, > > ... > > } OPTIONAL, > > features SEQUENCE OF SupportedFeatures, > > ... > > } > > > > An alternative approach would be to add a neededFeatures field at the > > highest level of the Setup-UUIE ASN.1 instead of inside the > > conferenceGoal structure, similar to the way the desirededFeatures and > > supportedFeatures fields will be added (see TD-50), like this: > > > > Setup-UUIE ::= SEQUENCE > > { > > [snip] > > --> neededFeatures SEQUENCE OF SupportedFeatures OPTIONAL, > > desiredFeatures SEQUENCE OF SupportedFeatures OPTIONAL, > > supportedFeatures SEQUENCE OF SupportedFeatures OPTIONAL > > } > > > > The motivation for adding neededFeatures to the conferenceGoal field was > > to force a call failure when trying to setup a call to pre-v4 endpoint > > and there is some v4 or later feature that is *required* for the call. > > The mechanism is intended to work like this: > > > > o The v4 EP sends Setup to the pre-v4 endpoint, and specifies some > > required feature in the neededFeatures field of the conferenceGoal. > > o The pre-v4 EP doesn't recognize the neededFeatures field as a > > supported CHOICE for a conferenceGoal, so it sends Release Complete. > > > > There would not be any conflicts with H.450, as suggested in the meeting > > report, because if the callIndependentSupplementaryService was needed, > > it would still be specified. The difference is that, if a neededFeature > > was also required, the H.450 goals would be specified inside the > > NeededFeatureGoal structure, which v4 and later endpoints would be aware > > of. > > > > These are the pros and cons of adding neededFeatures to the > > conferenceGoal vs. adding it to Setup-UUIE, IMO: > > o Advantages: > > - *May* force an early call release if a required feature is > > not supported by a pre-v4 endpoint. > > o Disadvantages: > > - ASN.1 and thus implementation would be more complex. > > Potentially have to check the conferenceGoal in two structures > > instead of one. > > - If pre-v4 EP sends Release Complete, there is no way to > > know whether it was sent because of an unrecognized > > conferenceGoal, because there is no ReleaseCompleteReason > > defined for that purpose. > > - H.323 does not require failing a call if the conferenceGoal > > is unrecognized, so the mechanism may not work at all. > > > > Although I think this mechanism is a good idea (and I supported it in > > Osaka), at this point I don't think it would work reliably enough to > > justify the added complexity. So I would prefer the alternative > > approach described above, adding the neededFeatures field directly to > > the Setup-UUIE. > > > > Okay, fire away. :-) > > > > Regards, > > Rich > > -------------------------------------------------------------------- > > Richard K. Bowen Cisco Systems, Inc. > > VoIP Session Protocols Research Triangle Park, NC, USA > > -------------------------------------------------------------------- > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > For help on this mail list, send "HELP ITU-SG16" in a message to > > listserv(a)mailbag.intel.com > > -- > -------------------------------------------------------------------- > Richard K. Bowen Cisco Systems, Inc. > VoIP Session Protocols Research Triangle Park, NC, USA > -------------------------------------------------------------------- > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > For help on this mail list, send "HELP ITU-SG16" in a message to > listserv(a)mailbag.intel.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv(a)mailbag.intel.com

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