Hi, All:
Let me add a little.
An H.323 entity needs to have the capability to support RAS messages. However, whether the RAS messages will be used or not before the call setup is up to that entity.
Best regards, Radhika
-----Original Message----- From: Chris Wayman Purvis [mailto:cwp@ISDN-COMMS.CO.UK] Sent: Thursday, November 30, 2000 8:56 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: Third party registration/group registration
Charles,
This comes up on this list every now and again, and the answer doesn't change. The gatekeeper is an optional entity: TRUE. RAS is optional: FALSE. Endpoints (including gateways, IWFs, whatever you want to call them) have a responsibility of trying to find one, registering with one if it can and SHUTTING ITSELF DOWN if it manages to find one or more gatekeepers but fails to register. Only if all reasonable attempts to find a gatekeeper fail should an H.323 endpoint operate without an active registration.
Let me give you the first couple of quotations from H.323 (I'm looking at v4 determined, but I don't believe this has ever changed) I find on the subject. They're in section 7.2.2: "As part of their configuration process, all endpoints shall register..." "Registration shall occur before any calls are attempted and may occur periodically as necessary (for example, at endpoint power-up)."
Oh, and I suggest reading H.225.0 section 7.7 "Required Support of RAS messages" as well.
How else could things work? Consider the case where an endpoint (A) is trying to make a call to another endpoint (B). A issues an ARQ to its gatekeeper, asking permission to try a call; the gatekeeper rejects the call (ARJ) on some reasonable grounds (possibly a conceptual "do not disturb" notice B has set up with its gatekeeper). A thinks "stuff this", unregisters from its gatekeeper ("we don't want to worry about all that boring RAS stuff if it's going to be inconvenient to us") and sends the Setup message to B anyway - resulting (at best) in an disgruntled B. In other words, as soon as you allow endpoints to operate in the presence of a gatekeeper without registering with it and abiding by its decisions, you might as well write all xRJ messages out of the protocol entirely!
If an endpoint is going to ignore RAS (and hence the standard) then why should it bother having anyone else register on its behalf? I refer you to "Besides,..." in my last mail (which point you still haven't addressed).
Regards, Chris
"Agboh, Charles" wrote:
Chris,
RAS IS OPTIONAL!!!! The GK is an OPTIONAL H.323 entity.
charles
-----Original Message----- From: Chris Wayman Purvis [mailto:cwp@ISDN-COMMS.CO.UK] Sent: Thursday, November 30, 2000 12:49 PM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: Third party registration/group registration
Charles,
The answer to your first question depends on the capabilities of D. RAS is OPTIONAL so I could have a D device that does not implement RAS. In my last email, the "third-party" would be a C device and
"first-party"
would be a D device (second-party is the A device) .
RUBBISH! RAS is NOT optional. See Table 18/H.225.0. Besides, how would your crippled H.323 endpoint tell its RAS handler to
send
the various RAS messages (like for instance ARQ to ask permission to make
a
call...)?
Regards, Chris
Regards,
charles
-----Original Message----- From: Chris Wayman Purvis [mailto:cwp@ISDN-COMMS.CO.UK] Sent: Thursday, November 30, 2000 10:43 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: Third party registration/group registration
Charles,
In your definition of "third-party" registration, consider a scenario involving four entities: an H.323 endpoint (A), an H.323 gatekeeper (B), a gateway/IWF/registering-entity (C) and an entity of some sort on whose behalf C is registering (which we'll call D). Assuming that B is not routing call-signalling, to which entity would A send its "Setup" message in
order
to contact D?
If the answer to this question is "C", this is well-covered in the
standard
it is simply that the term "third-party registration" is not used for
it.
It is simply viewed as C registering (potentially) lots of aliases. This parallels Tom's second case. If the answer is "D" (parallelling Tom's first case), then D is a very
odd
device (it can't be a full H.323 implementation or it would register for itself). Why have a device implementing all of H.323 except gatekeeper registration? After all, D would have to handle all the rest of RAS for itself
- what would it be gaining by not registering on its own behalf?
In the same scenario, to what entities are you referring, respectively,
as
the "third-party" in your latest contribution?
PLEASE clarify your definitions of "first-party" and "third-party" in
cases
where you use these terms. I am certain that the ends you are trying to achieve are perfectly possible - and not even that hard. Either will result, I believe, in a brief discussion with early consensus emerging. I believe
the
problems, and the large amount of mail this is generating on this list,
come
about entirely from the use of these terms without anyone understanding exactly what is meant by them.
I agree with Tom that once we can agree on terminology we can move on
quite
easily, and thank him for his usual high-quality clear-sighted input.
Regards, Chris
The registration feature allows endpoints to bind their identities to transport address(es) at the GK. This is well described in H.323. When an
endpoint
delegates another endpoint to perform this fearture on its behalf the definition in H.323 is not there. The signaling that follows the registration whether, its first or third-party may interrogate this binding. The third-party registration feature can enhance the user experience much more than a
normal
first-party registration. I don't believe that the third-party has to be in the signaling flow that may follow the third-registration. I agree with Tom-PTs
view.
Best regards,
charles
-----Original Message----- From: Tom-PT Taylor [mailto:taylor@NORTELNETWORKS.COM] Sent: Wednesday, November 29, 2000 7:39 PM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: Third party registration/group registration Accurate terminology is obviously useful, but in this case, at
least,
it
looks like something people can agree on and then move on. The more important point seems to be the underlying distinction in
requirements:
-- register on behalf of H.323 endpoints -- register on behalf of other endpoints where I use "other" in the sense that the contact address isassociated
with a non-H.323 signalling protocol. Purity is beside the point here
--
it's the intention of the contact address that matters. Stating therequirement in this way makes it obvious that the second requirement includes the need to state which protocol the endpoints expects to receive.
There is another possibility, of course: use the same mechanism tosatisfy all requirements, and allow for the possibility that the endpoint supports multiple protocols. I think the design would be cleaner if
we
took the approach: one contact point, one protocol -- even if it meant repeating the contact information for each protocol a multiprotocol endpoint supports.
-- Dr Chris Purvis -- Development Manager ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road Winkfield Row, Berkshire. RG42 6LY ENGLAND Phone: +44 1344 899 007 Fax: +44 1344 899 001
For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.comFor help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com
-- Dr Chris Purvis -- Development Manager ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road Winkfield Row, Berkshire. RG42 6LY ENGLAND Phone: +44 1344 899 007 Fax: +44 1344 899 001
For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com
-- Dr Chris Purvis -- Development Manager ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road Winkfield Row, Berkshire. RG42 6LY ENGLAND Phone: +44 1344 899 007 Fax: +44 1344 899 001
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com