Hi, Everyone:

It is an attempt to streamline our discussions for the conference call (April 17) so that we can save time while I am my inputs.

We have seen some contributions in solving the problems for intra-zone (AT&T), inter-zone/intra-domain (Alcatel, AT&T, and Ericsson [?]) and inter-domain (Alcatel and Ericsson) communications.

Here are some high-level comments and proposed combined proposal related to those contributions: 1. Intra-Zone, 2. Inter-Zone/Intra-Doamin, and Inter-Domain.

1. INTRA-ZONE

AT&T contribution (MD-017) deals with the intra-domain communication that describes: a. Mobile communications environments, b. Discovery, c. Registration, and d. Intra-Network Roaming. However, some aspects of Alcatel's contribution (MD-0XX) can be applicable for intra-zone communications as well.

A. Mobile Communications Environment

The highly cellular (wireless)-based mobile environment where 100s and 1000s of users entering and leaving a cell requires that the new discovery message like MGA (AT&T's contribution MD-017) is needed to discover the GK for signaling EFFICIENCY (while GRQ either multicast or non-multicast can be used in complimentary manner if the MGA message is not received within a certain period of time). It may be mentioned that mobile IP also uses the similar mechanism in the network layer for discovery.

B. Discovery

MGA message, which is appropriate in a highly mobile environment as stated in A, will discover the GK. The same discovery mechanism can be used for all cases: Intra-Zone, Inter-Zone, and Inter-Domain.

Proposal to accept the New MGA Message for Discovery:

· Let us accept the new MGA message for discovery (in combination with GRQ/GFC/GRJ message with multicast/non-multicast) that can be used for all cases: Intra-Zone, Inter-Zone, and Inter-Domain.

C. Registration

Like Rec. H.323 , this contribution is consistent with the fact that the association of the mobile entities has to be made with the GK through the GK.

The same registration mechanism can be used for cases: Intra-Zone, Inter-Zone, and Inter-Domain.

However, we believe that the HLF identities, like Alcatel's contribution (and VLF identities like Ericsson's to make their proposal consistent with the H.323 standard) contribution can also be passed during the registration process.

The important point that I am making is that the HLF and VLF Ids, previously not known to the mobile, can be passed to the mobile by the GK during the registration confirmation (RCF).

Proposal for the extended RRQ/RCF/RRJ:

· The proposal is that we can combine AT&T, Alcatel, and Ericsson proposal together to create the new extended RRQ, RCF, and RRJ message that can be used, as indicated above, for the mobile environment in all cases: Intra-Zone, Inter-Zone, and Inter-Domain.

2. INTER-ZONE (INTRA-DOMAIN)

Both AT&T (MD-018) and Alcatel (MD-0XX) address the inter-zone/intra-domain communications that are consistent with the H.323 standard.

A. Discovery

AT&T (MD-018) describes the discovery of the GK using the MGA message if the GK is not priori known.

Proposal:

· Let us accept the new MGA message as stated above for discovery in the highly mobile environment.

B. Registration and Location Updates

For registration, both AT&T (MD-017) and Alcatel (MD-0XX) contribution are in consistent with the H.323 standard because the association of the mobile entities are done via the GK.

However, there some minor variations in these two proposals that seem to be complementary. For example, AT&T contribution describes that there are couple of possible ways for exchanging the mobility related information: Extension of LRQ or Creation of New Mobility Binding Messages for intra-domain (Extension of accessRequest Message or Creation of New Mobility Binding Messages for inter-domain).

Ericsson's proposal shows that we need to extend the LRQ message.

In addition, we can add HLF Ids as stated earlier (we can also reconcile Ericsson's proposal to pass the VLF Ids during the registration).

It has to be clarified whether the pre-call setup messages like ARQ/ACF/ARJ messages to be extended or not.

Although Alcatel's proposal shows only one registration scenario with one HLF architecture, it is also possible to have other scenarios as shown in AT&T's contribution using the SAME protocol.

· Proposal for the extended RRQ/RCF/RRJ:

The proposal is that we can combine AT&T, Alcatel, and Ericsson proposal together to create the new extended RRQ, RCF, and RRJ message that can be used, as indicated above, for the mobile environment in all cases: Intra-Zone, Inter-Zone, and Inter-Domain.

· Proposal for Location Updates related to Mobility:

The proposal is that we can combine AT&T and Ericsson proposal together to have all the mobility parameters for the mobile users in the signaling messages for intra-domain communications either creating new mobility binding messages or extending the LRQ/LCF/LRJ Messages (advantages and disadvantages of the two methods can seen in AT&T proposal).

· Proposal for ARQ Message:

We need to investigate whether the ARQ/ACF/ARJ messages to be extended.

C. Call Establishment

Once we decide about discovery, registration, and location update messages, the call establishment can be done in several ways. The call scenario shown in Alcatel's proposal is one of the reasonable ways to do this. AT&T may also like to explore the alternative call scenarios in the subsequent contributions as well so that we can discuss pros and cons for each.

The most important conclusion seems to be that we do NOT need to create any new signaling messages for the call establishment.

3. INTER-DOMAIN

Both Alcatel (MD-0XX) and Ericsson (MD-0XX) have contributions in this area. AT&T plans to bring new contributions in this area.

However, it appears that Alcatel's contribution is consistent with the H.323 standard because it uses the pre-call setup messages (e.g., ARQ) in association with the GK (which is foundation of the H.323 standard).

It is very important to note that Alcatel's proposal shows that the new locationQuery message is going through the BEs of two different administrative domains.

In AT&T proposal (MD-018 and earlier contributions), it has been suggested that we need to investigate whether can extend the accessRequest message of H.225.0 Annex G because these message sets are very efficient.

However, the mobility related parameters proposed in AT&T contributions (MD-017 and MD-018) should also be present.

Ericsson's proposal appears that it is NOT associating itself with the GK for registration. It is rather by-passing the GK and is registering with the VLF directly. It seems to be that it is breaking the basic foundation of the H.323 standard. It is almost like creating a NEW protocol.

Alcatel's proposal and discussions in AT&T's contributions reveal the fact that we do not need to break the foundation of the H.323 standard to extend H.323 to support mobility.

I have also shown how Ericsson's proposal can be accommodates in the context of AT&T's and Alcatel's proposals for registration messages.

· Proposal:

· To accept the logical step to associate the information of the H.323 mobile users for registration via the GK as shown in AT&T's and Alcatel's proposals that conforms to the H.323 standard. · Decide whether we extend the accessRequest messages of create new messages for mobility management in H.225.0 Annex G. · To include all mobility related parameter as proposed in AT&T's, Alcatel's, and Ericsson's proposal.

I like to see that other members also provide their comments.

Best regards,

Radhika R. Roy AT&T +1 732 420 1580 rrroy@att.com