Orit,
Based on this email, we have not agreement at all.
1) I am not
interest at all in developing an addressing scheme for the sole reason that it
mimics the addressing schemes used by SIP. SIP is very oriented towards the concept of domains defined
by DNS and a user in that domain.
H.323 is oriented towards administration domains defined by one or more
gatekeepers and users attached to those gatekeepers. The only commonality is that a gatekeeper can be a server
with a name defined by DNS. These distinctions
must remain.
2) It is
unacceptable to force the implementation of annex G on any endpoint, gatekeeper
or administrative domain. Therefore
the differentiation between the use of Annex G or the use of LRQ should not
known to the originating endpoint.
The differentiation should be that this address defines the destination endpoint
(direct relationship) or it defines a source for resolving the destination
endpoint address (indirect).
In my view, in the direct relation a SETUP message is
routed towards the entity defined by the DNS where the user portion is
resolved. This may be direct
routed or gatekeeper routed, it does not matter. The endpoint defined by the DNS may be a gatekeeper or the
endpoint itself where the user portion defines one of multiple users on that
endpoint.
For the indirect relationship, the endpoint must
resolve the address of the destination address before sending the SETUP
message. Based on
H.323 procedures, the endpoint sends ARQ to its GK. How the GK resolves the address is within the capabilities
of the GK. It may use Annex G, it
this is possible. Or, it may fall
back to LRQ to the entity specified by the DNS name.
3) The
definition of an H.323 URL cannot be the vehicle to implicitly define new
procedures for address resolution.
If a new procedure for address resolution is to be defined, it must be
explicit, and it must be clear. These requirements have not been realized. I have seen no procedural text that has
full agreement. I have seen Annex
O as a working document, but this is a year from closure. I expect to have many discussions on
this subject in future meetings (note the plural). The H.323 URL we have for November must support the existing
H.323 procedures without any implicit extension or modification.
I think that Paul’s proposal meets the requirements that I have stated.
Where does this leave us now?
Bob
------------------------------------------------------------------
Robert
Callaghan
Siemens
Enterprise Networks
Tel:
+1.561.923.1756 Fax:
+1.561.923.1403
Email: Robert.Callaghan@ICN.Siemens.com
------------------------------------------------------------------
-----Original
Message-----
From: Orit Levin
[mailto:orit@radvision.com]
Sent: Friday, September 08, 2000
3:57 PM
To: Paul E. Jones; Robert (Bob)
Callaghan
Subject: Re: Re: Revised H.323 URL
document
Hello Paul
and Bob!
I prepared
the following "speech" for the mailing list, but it is
definitely better to try to understand each other first...
---------------------------------------
I hate to
disappoint you, but I would strongly disagree with the proposed
"mode" terminology.
I will try to
explain below, why it does not fit the URL concept.
1. The MAIN
purpose of URL is to use the Internet DNS Infrastructure
for SERVICE+ADDRESS resolution ACROSS the DOMAINS.
(The use of
the "user-only" URL is [just] a possible additional feature.)
2. The H.323
"direct vs. routed" concept specifies the relations
between an End Point and ITS Gatekeeper. It is an local
policy issue WITHIN their zone.
Today,
according to H.323 specification, the real flavor of the operational mode
in the DESTINATION zone is UNKNOWN (and irrelevant) to the originator
of the call.
Not
mentioning the future possible GK decomposition!...
3. Following
the proposed "mode" terminology, I guess, "routed" would
mean "LRQ" or "Access Request" and "direct" would
mean "Setup". In reality, the LRQ would lead to the "direct
call" and the Setup would lead to the "routed call". And how to
distinguish between the all three?
4.
The INTER-ZONE communication haven't been solidly defined so
far. (LRQ ? Annex G?)
The INTER-DOMAIN
communication is the subject of H.225.0 Annex G.
The URL
approach is an OPTION for all of the "intra" and
"inter" H.323 Zone and H.323 Domain cases.
It may
be used as a first lookup, before the LRQ or Annex G are performed.
It may
also have an overlapping functionality with LRQ and with very specific PARTS of
Annex G.
The relations
between the H.323 URL and H.225.0 "Annex G" are very close to
those of the SIP-URL and TRIP in a "SIP system". Both have
their uses and complement each other.
5. The
proposal is to have a possibility to "publish", using the URL, the
first procedure, to be issued towards the destination "domain".
By its
nature, it is not an issue for standardization. It is a policy of the
destination domain, which also is responsible for the URL itself.
The first
procedure (i.e. the "method") required for establishing of a specific
call across domains/zones can be either of the following:
-
H.225.0 Annex G/AccessRequest
-
H.225.0/LRQ
-
H.225.0/CALL SETUP
Once, the
first message is issued towards the destination (which is a result of DNS
lookup using the URL), the rest of the procedures are, indeed, very
well defined by H.323 and H.225.0 Annex G all together.
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@radvision.com
-----Original Message-----
From: Callaghan, Robert <Robert.Callaghan@ICN.SIEMENS.COM>
To: ITU-SG16@MAILBAG.INTEL.COM <ITU-SG16@MAILBAG.INTEL.COM>
Date: Thursday, September 07, 2000
8:17 AM
Subject: Re: Revised H.323 URL
document
Paul,
I definitely like
"mode" as a replacement for "protocol." It clearly represents the required
procedure without over doing details.
I think that we got it.
Bob
------------------------------------------------------------------
Robert Callaghan
Siemens Enterprise Networks
Tel: +1.561.923.1756 Fax:
+1.561.923.1403
Email: Robert.Callaghan@ICN.Siemens.com
------------------------------------------------------------------
-----Original Message-----
From: Paul E. Jones
[mailto:paulej@acm.org]
Sent: Wednesday, September 06,
2000 11:20 PM
To: Robert Callaghan; Orit Levin;
ITU-SG16@mailbag.cps.intel.com
Subject: Revised H.323 URL
document
Orit, Bob, et al,
Attached is the revised section covering the syntax of the H.323
URL. This (I hope) includes all of the changes we have discussed so
far. I am not sure that we settled on the "mode" parameter, but
I made the change here in this document-- feedback is welcome.
Best Regards,
Paul