1. June 2006 Roles of Session Border Controllers in IMS Networks CANTO - June 2006

2. Agenda Session Border Controllers What is an SBC? Why are Service Providers using them today? IP Multimedia Subsystem (IMS) What is IMS? Why are Service Providers evolving to IMS? SBC’s in IMS Networks What functions do they provide in the IMS Network? How will SBC’s evolve within the IMS architecture? Conclusions Summary References

3. SBC Role Today - ‘Session Aware’ Core SIP Infrastructure Session Border Controller SIP Normalization IPv6 / VLAN Topology Hiding DoS Prevention Firewall/NAT Load Balancing Session QoS Simplify, Protect and Offload Access Network Peering Network

4. Firewall/NAT Traversal Firewalls/ NATs SIP Services : SIP Proxy Application Server Media Server Session Controller SIP Endpoints Solves Firewall/NAT traversal from within the service provider network – Do not have to replace existing firewalls/NATs Offloads SIP Proxy – up to 20,000 re-registers a second Access Networks Simplify & Offload

5. DoS Attack Prevention Provides protection against Denial of Service (DoS) attacks in the form of SIP signalling Provides policing of individual media sessions Example – Users Signal G.711 (voice) call, but transmit video RTP session -> Maintaining QoS for other users Access Network Core Network SIP Services Session Controller Protect

6. Topology Hiding Provides protection against Denial of Service (DoS) by hiding internal IP addressing Removes sensitive IP addressing and domain names from SIP headers and SDP Access Network SIP Services Session Controller Protect Peering Network 200.2.x.x 17.3.x.x 110.5.x.x

7. What is IMS? IMS = IP Multimedia Subsystem IMS is a network architecture that uses SIP to provide multimedia services over IP IMS is a technology which provides fixed/mobile network convergence Layered architecture that separates transport (media), control (signalling) and application functions What is TISPAN? Telecoms and Internet converged Services & Protocols for Advanced Networks) Standardize the migration of PSTN networks to a converged network using IMS as the core architecture

8. Catalyst for IMS Deployment

9. Who gains from Fixed/Mobile Convergence? Service Providers Optimized ‘all IP’ network reduces OPEX Opens the fixed market’s customers to mobile operators and vice versa. New revenue streams – ability to charge for services End Users Common service set available regardless of the device, the location the access medium New services available – location based Applications become more appealing with large subscriber base (Metcalfe’s Law)

10. Logical separation of applications & network elements Rapid application development No vertical silo solutions IMS Basics… IMS brings Enhancements to… User profiles Security Roaming QoS policy control Call Control Session Detail Records IMS architecture Functional separation Open Interfaces SIP Based on SIP

11. IMS Network Characteristics Access Independent – SIP over IP (Extensions for Mobile) Open Architecture - Functional Elements Integrated through Open Interfaces Security at Network Boundaries – Protect IMS Infrastructure Roaming – User gets same apps in Home or Visited Network Scalable Architecture IMS Network Access Network Access Network Peering IMS Network IP Mobile Network HSS

12. SBC Features NAT/Firewall Traversal Protocol Normalization Protocol Interworking VLANs Geographic Resilience DoS Protection Rate Limiting Topology Hiding Encryption Policy Enforcement Policing Session Admission Control Legal Intercept Emergency Call Handling Call Detail Records EMS SNMP Management Security Simplify and Protect PSTN Equivalence IMS/TISPAN Requirement Within IMS Scope

13. IMS Architecture with SBC’s I-CSCF * P-CSCF S-CSCF HSS BGCF MGCF Visited Network (Originator) Home Network (Originator) GSTN MG I-CSCF S-CSCF HSS BGCF MGCF MG GSTN IP-CAN UE P-CSCF Home Network (Terminating) PSTN Switches PSTN Switches P-CSCF IP-CAN UE IP-CAN PDF Registration I-CSCF Session Set up THIG SG UE Visited Network (Terminating) Directs Users to Home Network NAT/FW Traversal Emergency Call Handling HSS service lookup to select S-CSCF = SBC

14. TISPAN architecture – SBC Media DSL access, WLAN etc I-CSCF S-CSCF HSS BGCF MGCF I BCF Home Network (Originator) GSTN MG PSTN Switches UE IP-CAN C-BGF P-CSCF I-BGF Registration Session Set up = SBC Media path Session Policing Legal Intercept IPv4 to IPv6 Session Admission Control DSCP QoS Re-mapping Topology Hiding

15. SBC Migration to IMS Signalling Functions SIP Media Functions MEGACO/H.248 RTP/RTCP Control Plane Media Plane Signalling SBC Media SBC Media Functions Signalling Functions MEGACO/H.248 Media SBC H.248 1:N and N:1 models SCTP (standardized signalling transport) Signalling compression Separate signalling & media functions Independently scale signalling and media Physically separate the product architecture Signalling encryption IPSec/TLS

16. Benefits of Split Signalling & Media Emerging standards for converged networks (IMS, TISPAN, etc) dictate that separation is required Media functions can be deployed at the network edge, saving $$ required to backhaul the media traffic to a central location Physical locations can scale their signalling and media independently – Allows for flexible deployment Integrated SBC deployments can be upgraded to Distributed configurations at any time with total reuse of hardware Signalling SBC Media SBC Media SBC H.248 Signalling Media H.248 Signalling Media

17. Standards Organizations 3GPP - Defined IP Multimedia Subsystem (IMS) http://www.3gpp.org/ ETSI TISPAN - Defining migration to IMS for Wireline networks http://www.etsi.org/ 3GPP 2 - IMS for CDMA http://www.3gpp2.org/ MultiService Forum (MSF) http://www.msforum.org/ Open Mobile Alliance (OMA) http://www.openmobilealliance.org/ Internet Engineering Task Force (IETF) http://www.ietf.org

18. Conclusions Service Providers are moving to IMS/TISPAN architectures Service Providers should invest in SBC’s that are forward compatible with IMS SBC architecture that supports signaling and media separation is required Today, SBC’s provide a greater set of features, than IMS requirements define

19. Terminology 3GPP3 rd Generation Partnership Project A-RACFAccess Resource Admission Control Function AUCAuthentication Centre BGCFBreakout Gateway Control Function C-BGFAccess/Core Border Gateway Function GSTNGlobal Switched Telephony Network HSSHome Subscriber Server IBCFInterconnect Border Control Function I-BGF Interconnection Border Gateway Function I-CSCFInterrogating Call Session Control Function IP-CAN IP Connectivity Access Network IMSIP Multimedia Subsystem MGCFMedia Gateway Control Function NAPTNetwork Address and Port Translation P-CSCFProxy Call Session Control Function PDFPolicy Decision Function QoSQuality of Service RCEFResource Control Enforcement Function SBCSession Border Controller S-CSCFServing Call Session Control Function SPDFService Based Policy Decision Function THIGTopology Hiding Inter Network Gateway UE User Element

20. June 2006 Thank you www.newport-networks.com

21. SBC Signalling Functions In 3GPP wireless networks the SBC Signalling requirements are: Proxy Call Session Control Function P- CSCF function Interrogating Call Session Control Function (I-CSCF) Can perform Topology Hiding Interconnect Gateway (THIG) functions where required Contains a Policy Decision Function which can be externalized if required In TISPAN Converged networks the SBC Signalling requirements are: An Interconnect Border Control Function when interconnecting networks In TISPAN the PDF is defined as SPDF (Service based Policy Decision Function) P CSCF PDF IBCF SBC Signalling Functions THIG H.248 Control of Media Plane Diameter / XML to external policy databases = 3GPP defined function = TISPAN defined function I CSCF

22. SBC Media Functions Currently Null function in 3GPP In TISPAN architectures performs Access to Core Border Gateway Function (CBGF) Interconnect Border Gateway Function (IBGF) I / C BGF SBC Media Functions H.248 Control of Media Plane = 3GPP defined function = TISPAN defined function

23. TISPAN architecture with SBC’s UE I-CSCF* I BCF P-CSCF S-CSCF HSS BGCF MGCF I BCF Home Network (Originator) GSTN MG THIG I-CSCF* S-CSCF HSS BGCF MGCF MG THIG I BCF GSTN IP-CAN UE P-CSCF I BCF Home Network (Terminator) PSTN Switches PSTN Switches P-CSCF IP-CAN UE IP-CAN PDF Visited Network (Originator) Visited Network (Terminating) Registration Session Set up = SBC SIP-I