SIP in 3GPP August 12th, 2000 Adam Roach

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3GPP Network Model Gf Gi Iu Gi Mr Gi Ms Gi RUu MGW Gn Gc TEMT UTRAN Gr SGSN GGSN Mm Mw Legacy mobile Network Mc Cx Alternative Acces s Network Mh CSCF Mg T-SGW *) HSS *) Applications & Services *) MSC server GMSC server Mc D C SCP CAP MGW Nb Nc Iu R-SGW *) Mh CAP IP Multimedia Domain (multimedia by SIP, IETF RFC2543) CS Domain (multimedia by ITU H.324M) PS Domain CSCF

Different Kinds of CSCFs P-SCSF Visited B S-CSCF Home A P-CSCF Visited A 18 AB GGSN SGSN Radio Access Network GGSN SGSN Radio Access Network S-CSCF Home B 8 I-CSCF HSS I-CSCF HSS 5 16 Proxy CSCF: Provides emergency service breakout, triggers for locally- provided services, and number normalizing (per local dialing plan)

Different Kinds of CSCFs P-SCSF Visited B S-CSCF Home A P-CSCF Visited A 18 AB GGSN SGSN Radio Access Network GGSN SGSN Radio Access Network S-CSCF Home B 8 I-CSCF HSS I-CSCF HSS 5 16 Interrogating CSCF: Queries the HSS to find the correct S- CSCF. First point of contact for incoming call signalling.

Different Kinds of CSCFs P-SCSF Visited B S-CSCF Home A P-CSCF Visited A 18 AB GGSN SGSN Radio Access Network GGSN SGSN Radio Access Network S-CSCF Home B 8 I-CSCF HSS I-CSCF HSS 5 16 Serving CSCF: Provides subscriber services.

3GPP SIP Decisions SIP from terminal to network SIP between network call nodes

General Principles S-CSCFs may have different capabilities. Firewalling must be possible. Terminal and node behaviours should be consistent, regardless of whether the user is roaming. Follow IETF standards as much as possible. Service nodes are access independent. Serving CSCFs may reside in either home or roamed-to network.

(Ideal) Access Independent Network PSTN PSTN GW owned by traditional telco. Calling users subscribe; authorization/billing based on challenge/response model GGSN SGSN CMTS Broadband Access Providers (Wireless, Cable, DSL, etc.) Pay-per-view movie service using RTSP, hosted by backbone provider Service Node Worldcom Service Node Yahoo! Service Node My own machine with a multicast chat server for all my friends, connected through my broadband access IP Peer IP backbone networks Service Node

Short Term Network Picture IP PSTN Call Control PSTN IP Firewall Call Control IP Backbone Access

Location I-CSCF Home P-CSCF Visited GGSN SGSN Radio Access Network S-CSCF HSS Profile Selection of Serving Node Location (Home Execution) 2. REGISTER9. OK 1. REGISTER10. OK REGISTER 8. OK 67

Location I-CSCF Home P-CSCF GGSN SGSN Radio Access Network S-CSCF HSS Profile Selection of Serving Node Location (Non-Roaming) 2. REGISTER9. OK 1. REGISTER10. OK REGISTER 8. OK 67

Location I-CSCF Home P-CSCF Visited GGSN SGSN Radio Access Network S-CSCF HSS Profile I-CSCF Location Profile HSS Selection of Serving Node Location (Visited Execution) 2. REGISTER13. OK 1. REGISTER14. OK REGISTER 11. OK REGISTER 12. OK 67

S-CSCF I-CSCF HSS P-CSCF Visited I-CSCF MGCF/ T-SGW MGCF/ T-SGW MGW HSS GGSN SGSN Radio Access Network PSTN Visited-Domain Provided Service (e.g. 411 Directory Assitance) 4 5. INVITE INVITE tel: INVITE INVITE INVITE IAM 11. ANM 3 Updates URI

Non-Conversational Services GGSN SGSN Radio Access Network Web Server Web Server IP Backbone Media Server Media Server

Future Issues to be Decided Handling of Instant Messages (SMS). SIP “MESSAGE” seems a natural fit, but other ideas are being proposed Uses of MRF (Media Resource Function) node. Possible uses include: –Conference Bridge (both dial-in and spontaneous) –Transcoding –Streaming Media/Announcments

Wireless Services Implications IP backbone Access Called Access Caller Value added services Value added services Home API (S-CSCF) SIP Bearer Services oriented WireLin e Bearer Services oriented WLan Home API (S-CSCF) SIP Bearer Services oriented WireLin e TA? WLan FW? TA? GPRS Value added services Value added services UTRAN FW? TA? UTRAN GPRS Video/Audio/Signaling signaling

Conclusions 3G is dedicated to using SIP for call control. This development will allow a seamless integration of “smart” wireless terminals into the exploding information/communication IP networks. If deployed correctly, the transition to 3G networks will be a revolution in wireless communications unlike any previously seen.