TSG-SA WG3 (Security) meeting #9		TSG S3#9 (99) 496
7th – 9th December 1999, Helsinki

Agenda Item:	

Source:	Ericsson

Title:		References to Packet Switched Core Network Nodes

Document for:	Discussion and decision

Throughout the 33.102 specification there are numerous descriptions of procedures and functions that refer to both the Packet Switched and Circuit Switched Netowk domains.

However, many sections of this document refer only to Circuit Switched core network nodes eg. MSC/VLR and SN/VLR.  

This is predominant throughout most chapters and it would help clarify many areas of the document if the PS and CN domains were referred to appropriately when specification is made of procedures that apply to both domains.

It is thus proposed that references to Core Network (CN) nodes are made throughout the document with a definition added to describe a CN Node as referring to both VLR and SGSN Nodes.  For abbreviated terms it is suggested to refer to VLR/SGSNs when referring to VLRs and SGSNs.  In the case of a reference to an MSC/VLR and SGSN then this reference should be specifically made.
These suggestions should help clarify many areas of the document and make it easily understandable to all parties.
In order to clarify these concepts the following diagram has been included which is an extract from 23.121 (figure 4-8) which illustrates the split between CN domains.  
This definition could be described in Chapter 4 to help clarify the nature of the security architecture split between the two core network domains with the USIM responsible for maintaining security contexts in both network domains.

Figure 4-8: Overview of the UE registration and connection principles within UMTS for the separate CN architecture case when the CN consists of both a CS service domain with evolved MSC/VLR, 3G_MSC/VLR, as the main serving node and an PS service domain with evolved SGSN/GGSN, 3G_SGSN and 3G GGSN, as the main serving nodes,
Extract from RS23.121 – Figure 4-8