Roberto,
Tell me more...
Roberto Winkler wrote:
Edgar, all
thanks for the reply, but I have some more....
Again, with reference to the WAU, whose capabilities and role I still don't quite understand, I don't see how can it 'intercept' messages belonging to the RAS channel (i.e. addressed to or coming from the Gatekeeper), without a true redefinition of the whole system.
I disagreed with your last statement " without a true redefinition of the whole system". If we designed a system that needs to be redefined everytime we provide a new service then we did something wrong. It may be true for some other systems you are looking at, like G _ _ _ or 3_ _ _.
The Radio sub-system WAU is just a (GW) which provides the Radio Control Function (RCF) and bearer connection. It maintains the state of the radio links connections, for a given call, between the a user agent/terminal agent and the network as perceived by the RCF. It establishes, maintains, modifies and releases a radio and fixed line bearer connection between a mobile and the network.
The MT to WAU relationship we hope to re-use the Radio technology defined by UMTS/3GPP. The MT to H.323 IP relationship we plan to re-use the H.323 elements and the TIPHON system.
But, most important, I think that Mr. Martinez's contribution cannot be appreciated in its entirety without a clear and precise description of the functionalities and capabilities of the blocks in the proposed reference architecture, which I feel is missing from the picture as it is now. As a matter of example, with reference to the WAU, the following items should be clarified:
- capabilities and functions
- protocol stack
- differences to other Gateways
- differences to Gatekeepers
All of the above is already available in one form or another, it has been presented in other contributions I had provided to ITU and WG7. The contributions can modified specificity for the new H.323 Annex H 'user and services mobility" once the framework is agreed on. Plus Annex H it is open for contributions and you or anyone are welcome to provide some.
To my humble opinion, this should be the first task to be accomplished, before aiming at message flows.
We need both and will have both, but this is the same old problem that network architects face and everyone has their own opinion. I rather first know from a high level, what we are trying to provide before jumping in to details. Have you ever been asked to "show me a call flow or block diagarm" what you are trying to do? Call flows without the intended protocols message to be used, in a specific system makes little sense to me.
Regards, Ed
Thanks very much and best regards everybody
Roberto Winkler
Roberto Winkler Senior Researcher Fondazione Ugo Bordoni Via B. Castiglione, 59 00142 Rome Italy
tel +39 0654803411 fax. +39 0654804404 e-mail wnk@fub.it
Mail archive for TIPHON_WG7 can be browsed at the following url :
http://www.etsi.org/tiphon/mailing.htm
-- Forwarded -- Subject: Re: H.323 mobility draft Date: Mon, 06 Sep 1999 10:54:19 -0400 From: "Edgar Martinez [1]" martinze@cig.mot.com Organization: NSS-NAT To: Roberto Winkler wnk@FUB.IT CC: TIPHON_WG7@LIST.ETSI.FR References: 1
Dear Roberto,
Thank you for your comments.
Responses follow:
Roberto Winkler wrote:
hello I have the following basic questions about the document in subject:
- what does IMIS mean ?
ASN.1 data type IMIS in section 8.5 and the call flows is a typo it will be correct.
IMSI ::= TBCD-STRING (SIZE (3..8))
imsi IMIS OPTIONAL (typo in document) should be imsi IMSI OPTIONAL (correction)
- I have the impression that many message flows in section 8 break the
usual RAS channel definition, because messages that in the 'original' H.323 are exchanged between endpoint and gatekeeper are now intercepted by WAU, whose role (and mapping to UMTS architecture) is really unclear to me.
As an example, there is the GRQ/GCF exchange in 8.2.1.2 and ARQ/ACF exchanged between WAU and GK in 8.3.1.1.
The WAU is not that much different that a MCU or Gateway which may register a single Transport Address or multiple Transport Addresses. To the GateKeeper the WAU will look like (GW) end-point. Of course of we want to support wireless mobility some tweets will have to be done in the H.323 procedures to handle H.323 (MT) wireless or Fixed Terminal mobility. But, it should not beak the under lining core set procedures for basic H.323.
Text from H.323v3 section 7.2.2 http://standard.pictel.com/ftp/avc-site/Incoming/
7.2.2 Endpoint registration:
Registration is the process by which an endpoint joins a Zone, and informs the Gatekeeper of its Transport Address and alias addresses. As part of their configuration process, all endpoints shall register with the Gatekeeper identified through the discovery process. Registration shall occur before any calls are attempted and may occur periodically as necessary (for example, at endpoint power-up).
A Gateway or MCU may register a single Transport Address or multiple Transport Addresses. The use of multiple Transport Addresses may simplify the routing of calls to specific ports.
An endpoint shall send a Registration Request (RRQ) to a Gatekeeper. This is sent to the Gatekeeper's RAS Channel Transport Address. The endpoint has the Network Address of the Gatekeeper from the Gatekeeper discovery process
and uses the well-known RAS Channel TSAP Identifier. The Gatekeeper shall respond with either a Registration Confirmation (RCF) or a Registration Reject (RRJ). See Figure 8. An endpoint shall only register with a single Gatekeeper.
The RRQ may be repeated periodically (i.e. at terminal power-up), so the Gatekeeper shall be able to handle multiple requests from the same endpoint. If a Gatekeeper receives an RRQ having the same alias address and the same Transport Address as an active registration previous RRQ, it shall respond with RCF.
Snip...
Regards, Ed
Clarifications are appreciated
best regards
Roberto Winkler
Roberto Winkler Senior Researcher Fondazione Ugo Bordoni Via B. Castiglione, 59 00142 Rome Italy
tel +39 0654803411 fax. +39 0654804404 e-mail wnk@fub.it
Mail archive for TIPHON_WG7 can be browsed at the following url :
http://www.etsi.org/tiphon/mailing.htm
-- Edgar Martinez - Principal Staff Engineer Email mailto:martinze@cig.mot.com FAX 1-847-632-3145 - - Voice 1-847-632-5278 1501 West Shure Drive, Arlington Hgts. IL 60004 Public: TIPHON & Other Stds - http://people.itu.int/~emartine/ Private:TIPHON & Other Stds - http://www.cig.mot.com/~martinze/