[H.323 Mobility:] questions on MTD-016

Jaakko Sundquist jaakko.sundquist at NOKIA.COM
Thu Apr 13 08:19:51 EDT 2000


Hi Stephen,

I have a couple more questions.

First, what exactly is the BG in your contribution? I know that there is
such an element in GPRS and it is used in cases, when the visited PLMN
always routes the packets of the visiting user to the user's home PLMN. I
assume that this BG is supposed to serve a similar purpose, am I right?

Second, based on the above mentioned purpose of the BGs and to the fact that
in your contribution you state that the HLF selects a gatekeeper in the home
network of the user to which the terminal/user will be registered, I assume
that this model that you are proposing is only applicable for the "Virtual
Home Environment" model (i.e. service execution in the home network). Am I
right in this assumption, and if not, could you explain how this model could
be used in the "Service Execution in the Visited Network" model?

Furthermore, I would not use the terms home/visited network, because there
are evidently differing views on what a network means. I suggest that we use
the already defined terms Home/Visited Administrative Domain instead for the
meaning of home/visited network that I think you're thinking of.

-Jaakko

> -----Original Message-----
> From: EXT Stephen Terrill [mailto:stephen.terrill at ERICSSON.COM]
> Sent: 13. April 2000 14:42
> To: ITU-SG16 at mailbag.cps.intel.com
> Subject: Re: [H.323 Mobility:] questions on MTD-016
>
>
> Hi,
>
> I shall try to answer some of these questions below.
>
> Regards,
>
> ..//steve
>
>
>
> "Kumar, Vineet" wrote:
>
> > Stephen,
> >
> > I have a couple of questions on your contribution MTD-016.
> These are:
> >
> > 1. H.323 already has mechanisms for discovering the
> gatekeeper. Are you suggesting in your contribution that the
> terminal should discover the VLF instead of the visiting
> gatekeeper ? Or, are you assuming that the VLF is integrated
> in the visiting gatekeeper ?
>
> This can be discussed - I was of the opionion that we should
> discover the VLF and send the registration to the home
> environment after that.  However, we haven´t agreed on the
> role of the VLF, and visited gatekeeper, home gatekeerp and
> HLF - when we come to agree on what these are, my proposal may change.
>
> >
> >
> > 2. In H.323, authentication of the terminal and the
> gatekeeper is done at the time of discovery. In fact, in
> H.323 all messages between the terminal and the gatekeeper
> can be authenticated and the message integrity preserved. In
> your contribution, authentication is done at the time of
> registration. Why is this preferable to what is already in H.323 ?
>
> I would be interested to understand which gatekeeper you were
> considering should do the authentication.  I would assume
> that the real authentication would have to be done at home -
> as such it would be necessary to find the visited network
> services, and then register/authenticate at home.
>
> >
> >
> > 3. What is the reason for the information flow from the HLF
> to the home gatekeeper, and from the home gatekeeperr to the
> HLF ? I don't think we can assume that there is only one home
> gatekeeper that the terminal may be using. In fact, the home
> gatekeeper may not have any information about the user.
>
> I certainly don´t assume that there is only one home
> gatekeeper.  I assume that there will be a number of home
> gatekeepers, but perhaps only one (or few) HLFs.  In this
> case, we need an function to select the gatekeeper that the
> user is going to camp on - and this may depend on load,
> subscriber profile, policy - or a lot of things.
>
> >
> >
> > Regards,
> > vineet
>



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