TSG-SA Working Group 2 (Architecture) meeting #4	     TSGS2#4(99)294
19 - 22 April 1999 Yokohama

Source:    NTT COMMUNICATIONWARE
Subject: 	Proposed add to Draft UMTS 23.20, 
Protocol Archtectre of Radio Interface Layer 3 (GMM/SM) between UE and 3G-SGSN (revised S2-99273)
Purpose: 	for decision

1. Introduction

This contribution intends to clarify C plane radio interface protocol architecture in UMTS PS Service Domain.

2. Discussion

In GPRS radio interface protocol architecture, LLC instance is existing per user in order to multiplex Signalling (i.e. GMM/SM), User Packet and SMS for the user.
On the other hand, it is not the case in UMTS, i.e. signalling connection shall be established per user independent of the user data traffic channel.
Accordingly, LLC layer is unnecessary and should not be defined on the protocol stack for radio interface layer 3 in UMTS.

3. Proposal

It is proposed that the following text and Figure X should be incorporated in new chapter 7.x (7.x Structure of radio interface layer 3) of UMTS 23.20 and chapter 9.7 should be removed.

7.x Structure of radio interface layer 3

The signaling plane consists of protocols for control and support of the transmission plane functions. The following signaling planes are used in UMTS between UE and 3G-SGSN.

Figure X: Protocol Architecture for radio interface layer 3 towards the PS service domain

UMTS PS service domain Mobility Management and Session Management (GMM/SM): This protocol supports mobility management functionality such as PS attach, PS detach, security, routing area update, location update, PDP context activation, and PDP context deactivation.

4. Reference

[1]	 UMTS 23.20 Version 1.6.1  
[2]	 GSM 04.60 Version 6.3.0 , Logical Link Control (LLC) Layer specification
[3]	 UMTS TS S3.01 Version 0.0.4, UTRAN Overall Description