Mob ad hoc group progress

Jaakko Sundquist jaakko.sundquist at NOKIA.COM
Thu Apr 6 03:40:12 EDT 2000


Hi all,

Comments to Radhika's posting below...

Hi, Everyone:

We are again not in sink what is going on with respect to progress of our
work. Let me try again.

That is just what I was trying to say...


We have talked about Nokia's contribution MD-011. We have taught that this
provides a reference to start with. In that contribution, we have Figure 1:
Intra-zone all H.323 scenario. We have decided that we will go one step at a
time.
First of all the scenario is called all-H.323 scenario. The figures just try
to explain what kind of call models that scenario involves. What we have
decided is to go one scenario at a time (not one "call model" at a time).
Furthermore, it was evident in the last teleconference that the cases
illustrated in the figures were not adequate and they need to be enhanced.


Now what does this Figure 1 provides us? We are NOT sure unless we explain
in detail what this scenario means to us. We cannot go to the next step
unless we analyze what the scenario of Figure 1 provides us. It may or may
not provide new insights from H.323 mobility point of view, but it is our
starting point. We have to complete it first before we go for the next step.
In this simple case, a mobile entity will move from its home network to a
foreign network. This also requires mobility management: Change in network
point of attachment and its possible impact in H.323 system.

This is just what I mean. What do you mean by the above text? First of all I
don't know what you mean by home and foreign network. Are you saying that
inside one zone there are multiple networks (so that moving from the home
network to a visited network is possible while all the time being located
inside the same zone)? You are right in saying that we need to analyze this
call model also, but first we need to identify the different cases for the
user's location, i.e. both users at home domain, user-A at home domain &
user-B in a visited domain, etc.
Related to the above, we have already defined the terms Home Administrative
Domain, Visited Administrative Domain and Serving Administrative Domain in
the draft H.323 Annex H. I think that these definitions are very good
(thanks to Milo, you see that we do agree on some things once in a while ;-)
and they clearly bind the subscription of a user (or a subscriber) to a
Domain. My opinion is that this means that the Administrative Domains are
the areas that divide the H.323 system into home and visited areas from the
point of view of the user. In other words, I wouldn't necessarily even
define terms, such as, Home Zone or Home Gatekeeper, because the above
definitions already bind the home of a user to the whole domain, not a
particular zone. If we want to define the term Home Zone, I think it should
mean ANY zone inside the Home Administrative Domain, similarly a definition
for the Home Gatekeeper could be made.
Based on the above, we can assume that when a user is in his/her Home
Administrative Domain, the HLF that contains his/her information is also
inside that Domain and inter-domain communications are not needed for the
Mobility Management of that user. Similarly, if the user is in a Visited
Administrative Domain, inter-domain communications are needed for the
Serving Administrative Domain to contact the user's HLF. This will also lead
to different location management cases for e.g. the intra-zone all-H.323
call model.


Once we complete Figure 1, we will go for the next one: Figure 2 Inter-Zone
all H.323 scenario. Of course, this is a complicated one to provide better
scenario for mobility management: Change in network point attachment +
Change in zone (logical) point of attachment as well.

I think that this is a good way for an individual to work, but personally I
would like to see contributions that address more of these call models at a
time. We can, of course, deal with the contributions in the order that
Radhika is proposing, I have nothing against that.

A side note: We have defined VLF and HLF. VLF may be assumed to be
co-located within the GK. But let people explain the interactions including
VLF and HLF the way they prefer in their contributions. The contributions
themselves will justify how VLF and HLF should perform their functions. Let
us not mandate anything beforehand unless things are explained in the
contributions.

One thing I would like to ask the ad hoc group members, is that should we
assume at this point that the VLF is co-located with the gatekeeper (as a
"composite network element" illustrated in Figure 3 of the draft H.323 Annex
H). I think this could be a good assumption in the first version of Annex H,
because it seems that most of us are thinking that way already. It would
only mean that we wouldn't have to specify anything for the reference point
E, but leave it open in the first version of the annex, similarly as was
done with reference point B in the H.225.0 Annex G. Other composite network
elements could also be identified for the first version of the annex. I
think that this kind of grouping could conciderably simplify our work for
the first version by reducing the number of interfaces that we need to
specify. We should probably encourage contributions proposing the composite
network elements and perhaps discuss these contributions in a teleconference
(maybe not the next, but the one after that).

- Jaakko



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