H.323 URL

Orit Levin orit at radvision.com
Mon Jun 19 10:05:53 EDT 2000


RE: H.323 URLDear 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 at radvision.com
  -----Original Message-----
  From: Paul E. Jones <paulej at PACKETIZER.COM>
  To: ITU-SG16 at MAILBAG.INTEL.COM <ITU-SG16 at 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 at 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 at 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 at 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 at ICN.SIEMENS.COM] 
    > Sent: Friday, June 16, 2000 5:39 AM 
    > To: ITU-SG16 at 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 at ICN.Siemens.com 
    > ------------------------------------------------------------------ 
    > 
    > 
    > -----Original Message----- 
    > From: Paul E. Jones [mailto:paulej at 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 at icn.siemens.com> 
    > To: "'Orit Levin'" <orit at radvision.com>; "'Paul E. Jones'" 
    > <paulej at PACKETIZER.COM> 
    > Cc: "Mailing list for parties associated with ITU-T Study 
    > Group 16 (E-mail)" 
    > <ITU-SG16 at 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 at ICN.Siemens.com 
    > > ------------------------------------------------------------------ 
    > > 
    > > 
    > > -----Original Message----- 
    > > From: Orit Levin [mailto:orit at 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 at radvision.com 
    > > -----Original Message----- 
    > > From: Callaghan, Robert <Robert.Callaghan at icn.siemens.com> 
    > > To: 'Paul E. Jones' <paulej at PACKETIZER.COM>; 'Orit Levin' 
    > > <orit at radvision.com> 
    > > Cc: Mailing list for parties associated with ITU-T Study 
    > Group 16 (E-mail) 
    > > <ITU-SG16 at 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 at ICN.Siemens.com 
    > > >------------------------------------------------------------------ 
    > > > 
    > > 
    > 
    > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
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