Transcript SIP & SS7
SIP & SS7 James Rafferty, Cantata Technology Agenda September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • Overview • SS7 + SIP in the Converged Network • SIP and SS7 – – – – Applicable Standards Use Cases Challenges What’s Ahead? • Resources • Summary 3 www.ITEXPO.com Overview September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • 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 2nd generation wireless networks 4 www.ITEXPO.com SS7 + SIP in Converged Network September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • 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 5 www.ITEXPO.com SIP and SS7 - Applicable Standards September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • 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.1912.5: More extensive SIP-SS7 Mapping with “SIP-I” • SIP-I extends beyond SIP-T ; includes more SS7 fields – 3GPP TS 29.163: Similar to Q.1912.5 • This is part of the IMS suite of standards 6 www.ITEXPO.com Use Case: SS7 to SIP Conversion September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California Signal Transfer Point SS7 ISUP SS7 ISUP PLMN SS7 ISUP SIP IP Network SIP IP Phone Cell Phone 7 www.ITEXPO.com Use Case: SS7 Bridging via SIP-T September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California Signal Transfer Point Signal Transfer Point SS7 ISUP SS7 ISUP PLMN/RAN IP Network SS7 ISUP SIP - T SS7 ISUP PLMN/RAN RAN Protocols RAN Protocols Cell Phone Cell Phone 8 www.ITEXPO.com Use Case: Privacy of Identity September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California Enforce CLIP/CLIR setting on SIP Identity Headers CLIP/CLIR service on Privacy of Identity Signal Transfer Point SS7 ISUP SS7 ISUP PLMN SS7 ISUP SIP IP Network SIP IP Phone Cell Phone 9 www.ITEXPO.com Challenges September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • 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 10 www.ITEXPO.com What’s Ahead? September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • 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 11 www.ITEXPO.com IMS Architecture September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California IP Multimedia Networks Legacy mobile signalling Networks CS Network Mm Mb Mb CS BGCF SS7 signaling converted at edge I-CSCF AS Mm CS Mk Mk ISC Mw Mj Sh Cx C, D, Gc, Gr BGCF Mi Cx IMMGW MGCF Mc MRFP MRFC Mp Mb Mb Mg Mr Mb Mb HSS S-CSCF Dx SLF Mw Dx P-CSCF UE Gm Ut IMS Subsystem 3GPP TS 23.228 V7.2.0 (2005-12) 12 www.ITEXPO.com Resources September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • Internet Engineering Task Force: www.ietf.org – Provides RFCs for SIP, RTP and some aspects of SS7 / IP interworking – Hitchhiker’s Guide to SIP: • http://www.ietf.org/internet-drafts/draft-ietf-sip-hitchhikers-guide-03.txt • International Telecommunications Union: www.itu.int – Develops SS7 series of recommendations and NGN • Third Generation Partnership Program (3GPP): www.3GPP.org – Develops IP Multimedia Subsystem and related standards • Cablelabs: www.cablelabs.org – Develops standards for Cable use of IMS • Article: Integration of SIP and SS7 for Voice over IP – http://www.tmcnet.com/sip/0307/feature_articles_integration_of_sip _ss7_for_voip.htm 13 www.ITEXPO.com Summary September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California • 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 14 www.ITEXPO.com September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California Thank You! 15 www.ITEXPO.com