[H.323 Mobility:] MD-110 uploaded (new messages to H.225 Anne x G)

Jaakko Sundquist jaakko.sundquist at NOKIA.COM
Tue Oct 31 03:11:48 EST 2000

Hi Martin,

See my comments embedded.

> Hi Jaakko,
> I'm not certain, whether I really understand the purpose of
> the EncryptionToken.
> If I look at Annex G v1, H.235 Clear and CryptoTokens are
> always present in each Annex G message; they are conveyed
> within AnnexGCommonInfo and thus are already part of each
> annex G message. Thus, I would say, that EncryptionToken is
> somewhat redundant and we do not need that this way.

You're quite right, the encryptionToken certainly seems unnecessary, thus
I'll take it away from the contribution.

> The other question I have concerns AuthenticationRejection:
> Why do you reverse tunnel - that is, feed back - the tunneled
> message in the reject?

Well, this was just a thought that maybe it would be beneficial, if the
originating gatekeeper would receive the (presumably) same message it has
tunneled, so that it can make sure that the message indeed is the one it has
sent. On the other hand, since we are talking about communications taking
place through a route of trusted parties (also secured with H.235 methods),
maybe this kind of integrity check is unnecessary. What do you think?

> Finally a general question:
> Once there was a discussion that Annex G not only be used
> among Border elements as currently defined in the H.225 Annex
> Gv1 scope, but to extend its usage for mobility purposes. If
> this were true, then Annex G could be applied also between
> the GK-VLF/BE and between HLF/BE-AuF. What is the current
> status of that discussion?

I guess this issue hasn't been throughly discussed yet. My personal opinion
is that we should extend the usability of the H.225 Annex G protocol also to
other functional entities besides the BE. On the other hand, I would be
quite happy also, if we would limit the first version of H.323 Annex H by
not handling all the interfaces in the architecture diagram and concentrate
on the VLF - HLF -interface (with or without BEs) instead. The reason for
the latter argument is that I would assume that implementors might be quite
happy with co-located functional entities so that they would have a
GK/VLF/BE and HLF/AuF/BE elements, thus necessitating only the mentioned
VLF/BE - HLF/BE network interface.

Thanks for the mail, it was very useful.


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