1. Problem Statement: Packet Data Roaming Architecture Compatibility November 11, 2005

2. www.cdg.org 2 Background Packet Data Roaming Working Group created at Whistler IRT (September 2005) The Working Group had a conference call on 10/25/05 We discussed and established work priorities We identified Packet Data Roaming Operator Architecture Compatibility as a top priority

3. www.cdg.org 3 Problem Statement CDG Reference Document #79 recommends three different packet data roaming architectures: –SIP –MIP –L2TP Different operators prefer to use different architectures Different operators are able to support different combinations of these architectures for inbound roaming partners. Not all of these architectures are compatible

4. www.cdg.org 4 Matrix of combinations SIPL2TPMIP SIP NO ISSUESOLUTION AVAILABLE NO SOLUTION, BUT NO KNOWN INSTANCES L2TP NO RECOMMENDED SOLUTION IDENTIFIED NO ISSUENO SOLUTION RECOMMENDED IDENTIFIED MIP NO RECOMMENDED SOLUTION IDENTIFIED NO ISSUE Device Serve Network The following matrix identifies incompatibilities “Device” indicates the technology preferred by the roaming device “Serve Network” indicates the network technology available in the visited operator’s network

5. www.cdg.org 5 Notes on Compatibility Obviously, there should be no issues with the SIP->SIP, MIP->MIP, and L2TP->L2TP scenarios The roaming MS may support multiple roaming architectures –The roaming MS could accept MIP with fallback to SIP The visited operator often support multiple roaming architectures: –The visited network any combination of the 3 architectures More detail on each scenario is provided (other than same->same)

6. www.cdg.org 6 SIP->L2TP: Solution Available The MS requires SIP, but visited network offers L2TP Solution: Visited PDSN/LAC creates L2TP tunnel and terminates on LNS in CRX or visited operator network or home network Transparent to MS (thinks its getting plain SIP) CRX CRX Home Operator AAA RAN PDSN PCF Visited Operator AAA RAN PDSN LAC PCF Application Server LNS Requires SIP

7. www.cdg.org 7 SIP->MIP: Possible Issue? The MS requires SIP, but visited network offers MIP Visited operator’s PDSN forces MIP negotiation (won’t accept SIP) No solution, but no known instance where PDSN doesn’t support SIP Security and architecture policies may prevent SIP being offered CRX CRX Home Operator AAA RAN PDSN PCF Visited Operator AAA RAN PDSN FA PCF Application Server Requires SIP

8. www.cdg.org 8 L2TP->SIP: Definite Issue The MS requires L2TP, but visited network offers SIP SIP is negotiated, but the visited operator network doesn’t provide the LAC function No known solution; LAC function can’t be pushed to CRX CRX CRX Home Operator AAA RAN PDSN PCF Visited Operator AAA RAN PDSN PCF Application Server Requires L2TP LNS

9. www.cdg.org 9 L2TP->MIP: Definite Issue The MS requires L2TP, but visited network offers SIP MS will try and negotiate (SIP needed for L2TP), but visited PDSN will force MIP No known solution. SIP negotiation and LAC function needed. However, no known instances where PDSN doesn’t offer SIP. CRX CRX Home Operator AAA RAN PDSN PCF Visited Operator AAA RAN PDSN FA PCF Application Server Requires L2TP LNS

10. www.cdg.org 10 MIP->SIP: Definite Issue The MS requires MIP, but visited network offers SIP (no FA function) MS will try and negotiate MIP, but visited PDSN will force SIP – no FA No known solution; FA function needed for MIP. Can’t push FA function to CRX. CRX CRX Home Operator AAA RAN PDSN PCF Visited Operator AAA RAN PDSN PCF Application Server Requires MIP HA

11. www.cdg.org 11 MIP->L2TP: Definite Issue The MS requires MIP, but visited network offers L2TP (no FA function) MS will try and negotiate MIP, but visited PDSN will force SIP (for L2TP) No known solution; FA function needed for MIP. Can’t push FA function to CRX. CRX CRX Home Operator AAA RAN PDSN PCF Visited Operator AAA RAN PDSN LAC PCF Application Server Requires MIP HA

12. www.cdg.org 12 Discussion Points SIP support for MIP and L2TP networks L2TP->SIP has possible solutions Unsolved Issues: MIP->SIP/L2TP, L2TP->SIP/MIP Only total solution is for all networks to provide FA and LAC functions (or converge to a single approach!)