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.
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