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 is associated with a non-H.323 signalling protocol. Purity is beside the point here -- it's the intention of the contact address that matters. Stating the requirement 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 to satisfy 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.
-----Original Message----- From: Chris Wayman Purvis [ mailto:cwp@ISDN-COMMS.CO.UK
Sent: Wednesday, November 29, 2000 4:45 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: Third party registration/group registration
Charles,
The IWF (SIP-H.323 gateway) may terminate data (voice,
video, data) if it
determines that the call cannot go from end-to-end. An
entity outside of
the IWF may perform this function on behalf of the IWF. In
this case, this
entity would be under the influence of the IWF.
Right. But my point is that for a registration is to be called "third-party", the IWF would have NO part in the proceedings other than the registration stage. You appear to be ignoring my point about what entity is handling H.225.0/Q.931 and/or H.245 signalling, which I feel is the crucial part of what would make a registration "third-party".
By *true* H.323 entities, I meant an entity that *speaks*
ONLY H.323. The
IWF represents non-H.323 entities on the H.323 network.
Your "*true*" H.323 entity is an unusual beast indeed, given that the majority of H.323 devices around are either gateways (speaking another protocol) or PC-based (in which they generally "*speak*" large varieties of protocols for different purposes. In fact you restrict your definition of "*true*" H.323 entities to standalone IP phones. The fact that a device supports protocols other than H.323 does NOT make it any the less a "*true*" H.323 device in any reasonable definition of the word "true".
You are right, additive registration is NOT third-party
registration. Can
it be used as a means to achieve scalable third-party registration?
Additive registrations can, I believe, be used to achieve what you are trying to achieve. I don't believe it can be used to achieve what _I_ understand as third-party registration. Our disagreement is around the definition of the term "third-party registration", the difference in our definitions causing confusion.
I'll stick my neck out here and say that so far I believe consensus is with my definition (third-party registration as one H.323 entity registering on behalf of other entities which are H.323 except in their inability or unwillingness to register themselves with a gatekeeper) rather than yours (a gateway registering any device using any protocol with an H.323 gatekeeper). I will then promptly duck as I wait for the flack to fly!
Regards, Chris
-----Original Message----- From: Chris Wayman Purvis [ mailto:cwp@isdn-comms.co.uk
Sent: Tuesday, November 28, 2000 10:36 AM To: Agboh, Charles; 'ITU-SG16@mailbag.cps.intel.com' Subject: Re: Third party registration/group registration
All,
Please please PLEASE can we have some more opinions on this
important
definition, though. Charles and I simply disagree, and a
wider pool of
opinion is needed in order for consensus to be reached. Although I
disagree with
Charles's view I am willing to espouse it if that's the way
the majority of
experts see things. Without further input we'll simply go
round in circles.
Charles, All,
I believe the fundamental question about "third-partyness"
in this context
is what entity or entities will handle the H.225.0/Q.931 and or H.245 signalling. My understanding of the type of IWF you are talking about
(at least, the way
I would implement such a thing!) is that the IWF terminates
all signalling,
with RTP data going direct end to end. So it is the entity that
is performing
the registration that will handle all signalling (namely what
you in your
SIP-centred way call and IWF and I in my H.323-centred way
call a gateway!).
To me this is a fair definition of first-party. The only
thing the IWF is
not terminating is (voice, video and application) data. This
does not make the
registration third-party in my opinion. There is no
assumption (as far as I
can remember, anyway) that H.323 entities have to handle
their own RTP
sessions
- they are required only to exchange addresses to terminate
these sessions.
Simple question: What is your definition of a "*true* H.323
entity"? In
what sense is your gateway/IWF not a "*true* H.323 entity"?
Additive registration is NOT third-party registration by my
definition.
Regards, Chris
"Agboh, Charles" wrote:
Hi Chris,
I see what you mean. I think you are working under the
assumption that
the
"..other H.323 entities" are *true* H.323 entites. The
IWF may give the
impression that they are H.323 entities but it doesn't
mean they are.
In this model, I am assuming that the "third-party" is
receving all
signalling from the GK whether it (the GK) is in DRC or GRC mode.
Q: Do I really care if the "..other H.323 entities" are
*true* H.323
entities or not? A GK probably couldn't say if the
"first-party"
being
registered (the entitry being registered as apposed to
the entity
receiving the registration) is a *true* H.323 entity or not. A: It may be usefull. A GK can invoke a special feature
if it can
differentiate.
H.323v4 defines the additive registration feature, which by your
definition
is a third-party registration, right? So how does the GK
know that the
"first-party" is a *true* H.323 entitry?
Best Regards, charles
-----Original Message----- From: Chris Wayman Purvis [ mailto:cwp@isdn-comms.co.uk
Sent: Monday, November 27, 2000 6:19 PM To: Agboh, Charles Cc: 'ITU-SG16@mailbag.cps.intel.com' Subject: Re: Third party registration/group registration
Charles,
My undstanding of "third-party" registration is the
same as yours.
But,
in
some applications a registration by the IWF may not be
on its own
behalf.
These two sentences contradict each other. Please reread
my explanation
of
my understanding, as it is impossible for you to agree with
it and believe
what
you have written in the second sentence above. Unless I misunderstand your definition of an "IWF", which
I take to be
synonymous with a "gateway" as defined in the H.323
series of standards.
H.323v4 provides this feature (a way to bypass the UDP
packet size
limitation) for this same reason.
Does it make sense to have this?, If no, then why not?
SupportedProtocols ::= CHOICE { nonStandardData NonStandardParameter, h310 H310Caps, h320 H320Caps, h321 H321Caps, h322 H322Caps, h323 H323Caps, h324 H324Caps, voice ......., SIP SIPCaps }
This may make sense (and is what I meant when I referred to "supportedPrefixes"). If this is a way forward that you
believe would be
useful for SIP gateways I would encourage you to write a
formal proposal
to
an ITU SG16 experts meeting on this basis.
Regards, Chris
-----Original Message----- From: Chris Wayman Purvis [ mailto:cwp@isdn-comms.co.uk
Sent: Monday, November 27, 2000 10:41 AM To: Agboh, Charles Cc: ITU-SG16@mailbag.cps.intel.com Subject: Re: Third party registration/group registration
Charles,
Wrong in my opinion, but I would hope other experts
would express their
opinions too! The problem is I'm not sure whether this
is a question of
understanding or of detailed definition of the phrase
"third party" in
this
context. My understanding of the phrase "third party
registration" would be one
H.323
entity registering at a gatekeeper on behalf of other
H.323 entities.
My
understanding of the word "registration" of this
context is that it can
only
apply to H.323 entities. In this context the IWF can
be considered to
be
at
the extreme edge of the H.323 network, so any
"registration" it does is
on
its own behalf. Maybe what you actually want is some equivalent to the
supportedPrefixes
that arrived in version 2, for SIP gateways. Whatever we agree you want, though, I think it is worth
trying to reach
some
consensus among experts in this group as to what the
phrase "third
party"
means in this context - as your understanding and mine are clearly in disagreement.
Regards, Chris
"Agboh, Charles" wrote:
Chris,
There are applications where an IWF can register an
EP from one domain
into
another. This allows automatic visibility of EP
from one domain from
another. In this case the IWF is registering not
only itself but
other
EPs.
For this scenario, the third-party entity is the IWF, right?
regards,
charles
-- 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
-- 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
-- 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 001For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com