1. Packet Data Roaming Common Architecture Richard Xu Chief Architect richard.xu@aicent.com +1(408) 834-0217 Aicent, Inc. November 11, 2005

2. www.cdg.org 2 Background Reiterate what have been stated: 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

3. www.cdg.org 3 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

4. www.cdg.org 4 Extra IP Routing Issues Home network insists outbound roaming traffic coming back from CRX Home network allows outbound roaming traffic from Internet Serving network routes all inbound roaming user traffic to Internet for accessing home services No RECOMMENDED SOLUTION No ISSUE Serving network routes all inbound roaming users traffic via CGX NO ISSUENo RECOMMENDED SOLUTION Home Network Serving Network

5. www.cdg.org 5 Common Architecture Incorporate most roaming scenarios into a common recommended architecture for each CDMA operators based on existing CRX principles Simplify the provisioning process Future applications proven

6. www.cdg.org 6 Definition of roaming service elements At operator premise: –Core Subnet (CS): PDSN/FA/LAC, HA, AAA, MMSC(MM4 Interface) –Service Subnet (SS): Application Servers (WAP, PoC Server, MMSC, Email) –Roaming-in Subnet (RIS): IP Subnet assigned to inbound roamers PDSNHA AAALNS MMSC WAPPoC Roaming-In Sub BG FW/GW CRX Core Sub Service Sub Internet Internet

7. www.cdg.org 7 Definition of roaming service elements At CRX premise: –Core Backbone: routing for Core Subnet traffics –Virtual Home Subnet: subnet for hosted roaming elements, e.g. LNS for L2TP PDSNHA AAALNS MMSC WAPPoC Roaming-In Sub BG FW/GW CRX Core Sub Service Sub Core Backbone BG Proxy AAA Virtual Home LNS FW/GW Operator Internet Internet

8. www.cdg.org 8 New Service Element from CRX At CRX premise: –Virtual Home Subnet LNS fulfilling L2TP that is not supported by home network Tunnel connection to Home network Internet Access PDSN AAA BG CRX Visited Core Sub Core Backbone BG Proxy AAA Virtual Home LNS BG MMSC WAPPoC GRE BG GRE RIS Home Service Sub User Traffic GRE Tunnel L2TP Tunnel

9. www.cdg.org 9 Common Architecture for both CRX and Operator At operator premise: –GRE Tunnel terminating point (router) as extra element GRE Physical end-point (IP) belonging to Core Sub (routable via CRX backbone) At CRX Virtual Home Subnet: –Two GRE tunnel terminating points (routers) One tunnel to carry Service Sub routes The other tunnel to carry RIS routes –CRX only routes core sub and GRE tunnels traffics compliant with Doc#94 –Together with LNS in Virtual Home, the architecture resolves most mismatched cases except MIP  SIP, where MIP Client is required to fallback SIP BG Core Backbone BG GRE GRE Tunnel for Service Sub Roaming-In Sub Service Sub Core Sub RIS Service Subs Routing Mgr. GRE GRE Tunnel for RI-Sub Virtual Home Operator LNS

10. www.cdg.org 10 Roaming Scenario: SIP  L2TP Home Operator exchanges its service routes with virtual home via service tunnel if enforcing roaming-in via CRX. CRX injects tunnel related attributes in RAIDUS reply package to trigger visiting PDSN/LAC to build L2TP tunnel with LNS in virtual home. User traffic is either routed via service tunnel or internet depending on routes availability at virtual home. PDSN AAA BG CRX Visited Core Sub Core Backbone BG Proxy AAA Virtual Home LNS BG MMSC WAPPoC GRE BG GRE RIS Home Service Sub Service Tunnel L2TP Tunnel FW/GW Internet Service Subs

11. www.cdg.org 11 Roaming Scenario: L2TP  SIP Home Operator exchanges its service routes with virtual home via service tunnel if enforcing roaming-in via CRX. CRX remotes tunnel related attributes in RAIDUS reply package to ensure SIP. Visited Operator assigns inbound roamer with IP within RIS, and routes to GRE tunnel router where user traffic is either routed to virtual home or Internet depending on the routes availability managed by virtual home. PDSN AAA BG CRX Core Backbone BG Proxy AAA Virtual Home GRE BG MMSC WAPPoC GRE BG GRE RIS Home Service Sub Service Tunnel RIS Tunnel FW/GW Internet Roaming-In Sub GRE Visited Core Sub Service Subs

12. www.cdg.org 12 Roaming Scenario: MIP  SIP/L2TP MIP  SIP/L2TP –Assuming MIP Client supports the fallback-to-SIP features –The scenario is similar to either L2TP  SIP or SIP  L2TP, depending on home network preference SIP/L2TP  MIP –Assuming PDSN in mobile IP only visited network supporting either SIP or L2TP –The scenario is similar to either L2TP  SIP or SIP  L2TP, depending on home network preference

13. www.cdg.org 13 Summary Introducing Virtual Home with hosted LNS and GRE tunnel endpoints at both Virtual Home and operator premises help to bridge the gap among different roaming scenarios At operator premise, extra roaming element, the GRE router, requires minimum provisioning comparing to handling all different roaming scenarios CRX plays more mediation roles to enhance experience of CDMA data roaming The new revised architecture serves as interim solution until all PDSN could support all access requests. No impact on the future architecture, where CRX would just serve as core backbone for core subnets