Third party registration/group registration

Chris Wayman Purvis cwp at ISDN-COMMS.CO.UK
Fri Dec 1 09:41:00 EST 2000


> Gettin' closer.
I think (and hope!) so!

> Re Q2: I simply can't justify making the user wait several seconds for a
> discovery that will always fail in a system without a gatekeeper before he
> or she can place or answer each and every call. Can you? Therefore, the user
> should be able to turn off RAS.
So you'll agree on answer c then?
What about regular reattempts to find a gatekeeper (excluding my suggestion of
when a call is attempted).

> Re Q3: I agree with you, except that with some endpoints the user may then
> turn off RAS and place or answer calls without RAS. Note that the typical
> user will most likely not do this, since at least placing a call without a
> gatekeeper would require more knowledge than the average user posseses,
> e.g., the IP address of the called party.
This is where I disagree, on the grounds that if we allow calls in systems with
gatekeepers from endpoints that are not registered, we may as well throw away
the gatekeeper altogether (or at least call it a proxy and start speaking SIP).

> Re Q4: Maybe he has decomposed his endpoint. In the C Standard, there is
> something called the "as if" rule. Applying it here, if the system
> experiences consistent behavior from a possibly decomposed entity that is
> acting "as if" it were a corporate entity, it is compliant IMO. Who cares
> where messages originate as long as the effect is the same? In a different
> way, the "as if" rule is what allows routing gatekeepers to do what they
> do--they can fiddle with messages streams all they want as long as they
> maintain consistency "as if" the message streams were originating from a
> compliant endpoint.
Surely if the "as if" rule applies there can be no requirement for any changes
to the standard - otherwise it isn't "as if"!
I grant the possibility of the decomposed endpoint, although I don't personally
understand why anyone would want to, as the communication between the
decomposed parts would be at least as complicated as RAS itself.

> Note that when I say, "user," I mean either the actual user of the endpoint
> or possibly an administrator of the system. I think it's perfectly
> reasonable to make the use of RAS an administrated setting.


> -----Original Message-----
> From: Chris Wayman Purvis [mailto:cwp at ISDN-COMMS.CO.UK]
> Sent: Friday, December 01, 2000 3:46 AM
> Subject: Re: Third party registration/group registration
> Paul,
> I think we're starting to converge.  Let's separate this out now, into
> separate
> questions:
> Q1. Are endpoint devices (in which term I include gateways etc throughout
> this
> mail) required to implement RAS?
> A1. Yes (agreed between you and me, disagreed by Charles).
> Q2. How does an endpoint device know whether or not a gatekeeper is present
> in
> the system, and hence whether or not to use RAS?
> A2a (Your position as I understand it.)  Configuration, discovery on
> startup,
> give up if you don't find anything then.
> A2b (My suggestion) Configuration, discovery on startup, retry at some
> reasonable frequency (hourly?), take the three seconds to attempt gatekeeper
> discovery when someone makes a call to or from the endpoint in question.
> A2c (What we'll probably end up agreeing!)  Implementation decision.
> Q3. What should an endpoint do if it attempts to register with all
> discovered
> gatekeepers, where there is at least one gatekeeper in the system, and fails
> (RRJ)?
> A3a (My position) Shut itself down.
> A3b (Anybody elses) ???
> Q4. Is Charles's actual application, where one entity is registering and
> hence
> presumably (although he's consistently failed to clarify) handling RAS on
> behalf of another compliant H.323 endpoint a possibility?
> A4a (My position, with which I THINK you agree) No, on the grounds that if
> the
> gateway/IWF can find a gatekeeper and use it, so can the endpoint.
> A4b (Charles) Yes.
> This actually gives rise to a further question, which is (I believe) open,
> and
> probably shouldn't be:
> Q5. Can an endpoint be separated from its gatekeeper by a proxy?
> Regards,
> Chris
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Dr Chris Purvis -- Development Manager
ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road
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