TSG-SA  Working Group 3 meeting #8		Tdoc S3-99461
Sophia Antipolis, France, 16-19 November 1999

To:	R3, N1
CC:	R2
Source: 	S3 
Title: 	Response to liaison statement on Security Mode Control 
	procedure and CN handling of classmark information

S3 is pleased to provide the following comments to the proposed liaison statement ( TSGR3#7(99)D49 = S3-99436) from R3. At the same time we believe the information contained herein will cover the issues raised by N1 in their LS (Tdoc N1-99D06 = S3-99434).

1.	We confirm that the Security Mode Control procedure described is in line with S3 requirements.

2.	The verification of the UE classmark is feasible. We refer to our CR30 to TS 33.102 (Tdoc S3-99409 Handling of UEA and UIA capability information, attached) where the procedure is described.

3.	Network initiated reauthentication during PS services is required. User initiated reauthentication during PS services and network and user initiated reauthentication during CS services discussed in S3 but no firm decision has been made. S3 feels that it is still an open question if it is technically feasible (during ongoing traffic and without service disruption) and would like to receive information on the feasibility of the feature.

4.	The selection of the algorithms can be made by the RNC. The CR30 to TS 33.102 removes the requirement for the CN to handle the MS UEA and UIA capability information.