SIP & SS7 James Rafferty, Cantata Technology

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 3 Agenda Overview SS7 + SIP in the Converged Network SIP and SS7 –Applicable Standards –Use Cases –Challenges –What’s Ahead? Resources Summary

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 4 Overview SIP (Session Initiation Protocol) has won the IP Standards Wars SIP is an important part of the current and emerging IP Networks –Most new deployments use SIP –SIP is the key protocol for the IP Multimedia Subsystem (IMS) SS7 is the dominant signaling protocol used on Landline and Wireless networks –It has been particularly successful for 2 nd generation wireless networks

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 5 SS7 + SIP in Converged Network SS7 will typically be found on the edge of the converged network –ISUP (ISDN User Part) used for Call Control –TCAP (Transaction Capabilities Application Part) used for various database lookups such as Local Number Portability (LNP) and Caller Name Lookup (CNAM) SIP used for backhaul of signaling or in the core between gateways SS7 can either be converted to SIP or transported via SIP-T

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 6 SIP and SS7 - Applicable Standards Key SS7 Standards are from ITU, ETSI and ANSI –Country specific variants are very common; usually based on ITU or ANSI Latest SIP Standard is RFC 3261 –Many additional RFCs which document additional methods Several standards for SIP – SS7 interworking –IETF RFC 3372 – SIP-T Transfer ISUP elements via SIP with MIME body parts –IETF RFC 3398: SIP – SS7 Mapping Map ISUP parameters to SIP headers (where available) –ITU-T Q : More extensive SIP-SS7 Mapping with “SIP-I” SIP-I extends beyond SIP-T ; includes more SS7 fields –3GPP TS : Similar to Q This is part of the IMS suite of standards

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 7 Use Case: SS7 to SIP Conversion Signal Transfer Point IP Network PLMN SS7 ISUP SIP IP Phone SIP Cell Phone SS7 ISUP

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 8 Use Case: SS7 Bridging via SIP-T Signal Transfer Point IP Network PLMN/RAN Cell Phone Cell Phone SS7 ISUP RAN Protocols SIP - T PLMN/RAN SS7 ISUP Signal Transfer Point RAN Protocols

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 9 Use Case: Privacy of Identity Signal Transfer Point IP Network PLMN SS7 ISUP SIP IP Phone SIP Cell Phone SS7 ISUP CLIP/CLIR service on Privacy of Identity Enforce CLIP/CLIR setting on SIP Identity Headers

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 10 Challenges Tremendous amount of SS7 based infrastructure in place –Transition strategies for using SS7 and SIP together are critical to manage capital expenditures SS7 variants require switches and gateways which support the variants Non-standard uses of SIP are common and hard to eliminate once in the network Interop between equipment from different vendors is a “way of life” for the converged network –Best of Breed Enabling Technology Components –Creates opportunities for System Integrators

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 11 What’s Ahead? Lots of momentum behind IMS, which uses both SIP and SS7 –More formal model for SIP use at core –SS7 used at the edges and converted to SIP or SIP-I IMS Architecture Example Many operators not waiting for IMS –Wireline vendors making extensive use of SIP “as is” –SS7 network in place and working; easier to add SIP for backhaul or new services SS7 is well entrenched for services and will remain in place for years to come

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 12 IMS Architecture SS7 signaling converted at edge

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 13 Resources Internet Engineering Task Force: –Provides RFCs for SIP, RTP and some aspects of SS7 / IP interworking –Hitchhiker’s Guide to SIP: International Telecommunications Union: –Develops SS7 series of recommendations and NGN Third Generation Partnership Program (3GPP): –Develops IP Multimedia Subsystem and related standards Cablelabs: –Develops standards for Cable use of IMS Article: Integration of SIP and SS7 for Voice over IP – _ss7_for_voip.htm

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 14 Summary SS7 remains the dominant signaling protocol in today’s network SIP is the key next generation VoIP Protocol Integration of SS7 and SIP critical to leverage existing operator investments Several strategies possible for transition to more IP centric infrastructure Many vendors using SIP to build new services on their existing SS7 network IMS is coming, but not the only way forward for operators making IP investments

September 10-12, 2007 Los Angeles Convention Center Los Angeles, California 15 Thank You!