Draft Megaco Agenda

Tom-PT Taylor taylor at NORTELNETWORKS.COM
Mon Dec 4 16:34:27 EST 2000


Here are my opinions:

> Q1. Is a device permitted to call itself H.323 if it does not support RAS
> can be configured not to use RAS)?
> A1a (CWP). No, on the grounds that certain RAS messages are mandatory for
> devices to support (H.225.0 section 7.7)
> A1b (CA, PL). Yes, on the grounds that gatekeepers are an optional part of
> H.323 system.

I agree with CWP on this issue.  7.2.2/H.323 states:
  As part of their configuration process, all endpoints shall register
  with the Gatekeeper identified through the discovery process.

This means that they must be pre-configured with a GK or must perform
automatic discover-- i.e., they must support RAS.  It is acceptable for an
endpoint to continue operation of no Gatekeeper is found or if the
Gatekeeper(s) reject the registration requests. The last paragraph of 7.2.2
is there to indicate that an endpoint may continue in such a manner-- it is
just considered "unregistered".

> Assume RAS is being supported in a particular "system" (without prejudging
> answer to Q1), and we come to the other question:
> Q2. If an endpoint has attempted gatekeeper discover and/or registration,
> been rejected (GRJ or RRJ) by all gatekeepers it has found (this being at
> one gatekeeper), is the endpoint permitted to make and receive H.323
> A2a (CWP). No, on the grounds that there is a gatekeeper in control of
> system, and it has denied access.  Also on grounds of common sense (ARJ
> no sense if an endpoint may deregister and then make the call it's been
> refused).
> A2b (PL). Yes, presumably on grounds of restrictiveness.

I asked this question of the original H.323 designers. The correct answer is
PL's interpretation.  As noted above, the last paragraph of 7.2.2 was there
for this reason, but I'll admit it could be clarified a bit.

> Q3. Should third-party registration be standardised?
> A3a (CA). Yes.
> A3b (CWP). Possibly, but before this can be answered a LOT of
clarification is
> required on what is meant by the term "third-party".

I have my idea about what a 3rd party is, but it may differ from others'

A gateway could certainly register an address that could be used to reach
said 3rd party, but it's not really registering on behalf of the 3rd party--
it's acting as a gateway to that entity.

I suppose one could build a device that does register on behalf of H.323
endpoints.  Perhaps the endpoints communicate with this entity in a
proprietary manner and allow it to perform the RAS functions for the
endpoint.  I don't see a lot of value in such a scheme, because the
proprietary protocol would simply be doing what RAS does.

Now, I have seen some endpoints which do not support RAS and Gatekeepers
that allow static entries to be made in order to accommodate them.  I
suppose that's a "3rd party" registration-- but then, it's also done because
the endpoints are not compliant.

What would be the benefit of 3rd party registration?  (Keep in mind that a
GW that can reach the 3rd parties can register the appropriate aliases, but
it's not really "3rd party registration" in my opinion.)


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