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3GPP2 Broadcast and Multicast Service Contact: Jun Wang, Qualcomm Inc. jwang@qualcomm.com. Outline. BCMCS Standard Status and Schedule BCMCS Overview Architecture Capabilities BCMCS Security Framework Overview Review of CDMA 1x and HRPD BCMCS Radio Capabilities
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3GPP2 Broadcast and Multicast ServiceContact: Jun Wang, Qualcomm Inc. jwang@qualcomm.com Page 1
Outline • BCMCS Standard Status and Schedule • BCMCS Overview • Architecture • Capabilities • BCMCS Security Framework Overview • Review of CDMA 1x and HRPD BCMCS Radio Capabilities • BCMCS Phase II Work Items • OMA BCAST Overview • Conclusion and Recommendation Page 2
3GPP2 BCMCS Current Status and Schedule • Stage 1 Document (S.P 0030-A): • Published in February 04 • Security Framework Document • S.P 0083: Published • S.S 0083-A: Published in September 04 • Over-the-Air document: • 3G1x: C.S0001-D through C.S0006-D, published in February 04 • 3G HRPD: C.S0054, published in February 04 • BCMCS in cdma2000 wireless IP network (X.S0022) • Publication Version ready by pending 3 RFC numbers from IETF • IOS BCMCS (A.S 0019) • Published in November 04 • IS-683-C Support: Published at Oct 02 • R-UIM Support (C.S0023-C v1.0) • Currently in ballot process • Expected publication in June 05 Page 3
Overview • Optimize use of the cdma2000 radio interface over the air • BCMCS provides delivery of the IP flows that comprise BCMCS Programs (content) to one or more terminals in one or more regions of the 3GPP2 network. • The 3GPP2 operator has control of: • Transmission Areas of BCMCS IP flows • Billing of the user and/or content provider • Encryption of the IP flows • Examples: weather, stock, news, pay per view movies, sport events etc. Page 4
BCMCS Overview - Architecture BSN: Broadcast Serving Node MR: Multicast Router PDSN: Packet Data Serving Node AAA: Authentication, Authorization, and Accounting HAAA: Home AAA SAAA: Serving AAA PCF: Packet Control Function BSC: Base Station Controller MS: Mobile Station UIM: User Identity Module RADIUS: Remote Authentication Dial In User Service Page 5
Protocol Stack - Bearer Path Page 6
Basic Procedures • Service Discovery/Announcement • Used to find out available BCMCS service • Distribute information about the service, parameters required for information acquisition and program schedule • Via out of band mechanisms • Content Subscriptions • Subscriptions to BCMCS • RK (Registration Key) is provisioned • Via out of band mechanisms • Information Acquisition • Obtain BCMCS Session related info from Controller (BCMCS_FLOW_ID, header compression etc) • Obtain Security Parameters (BAK etc) • Content Availability Determination • Determines whether a Multicast IP flow is available/transmitting in a particular sector and the BCMCS radio configuration information • Via the overhead messages from a BS • BCMCS Registration • Request for delivering the IP flows in a particular sector • The first user may trigger the Bearer Path establishment • Notify where to page the MS • Reception of the Content • BCMCS Deregistration Page 7
Major Capabilities in X.S0022 • BCMCS Controller Discovery (via DHCP) • Information acquisition using HTTP • HTTP Digest is used for Information Acquisition Authentication • Program based authorization • Both Static and Dynamic Broadcast • Registration authorization (BAK Hash based mechanism) • Segment based Framing or HDLC-like Framing • Optional Encryption (Link layer or high layer) • SRTP is used for high layer encryption at Content Server • Link layer encryption at the RAN only applies to HRPD • Header Compression (ROHC U mode) • BSN/RAN session discovery (Query/Response Model) • Accounting • BAK Lifetime based accounting (for charging the MS user) • Octet based accounting (for charging the content provider) Page 8
Key Hierarchy for CS-MS Security SK (Session Key) • Used to decrypt content. • Changes frequently to discourage session theft • Generated by the UIM BAK (BCMCS Access Key) • Used to generate SK • Provides access to program/multicast IP flow • Decrypted and stored in the UIM TK (Temporary Key) • Used to encrypt/decrypt the BCMCS Access Key (BAK) for transmission to the MS • Generated from RK • Stored in the UIM RK (Registration Key) • Used to generate TK • RK is obtained when user subscribes to broadcast services • Stored in the UIM Page 9
Authentication for Information Acquisition • When the MS requests Security Information (BAK etc), the BCMCS Controller shall initiate authentication and program authorization procedures with Home RADIUS server • Authentication using IETF RADIUS Extension for Digest Authentication • Authorization on programs Page 10
TK is derived from RK [encrypted content, SK_RAND, BAK_ID] Provisioned RK [SK, SK_RAND, BAK_ID, BAK_Expire] Content is encrypted by SK SK is derived from BAK BAK BAK is encrypted by TK TK is derived from RK BAK Provisioned RK BCMCS Security Functional Architecture BAK_ID, SK_RAND Content 7 SK 2 BAK Is encrypted by TK 2 RK provisioned RK provisioned Page 11
SRTP (High Layer Encryption) • SRTP (RFC3711) framework is used • BAK is used as SRTP Master Key • SK_RAND (32 bits) is extended to 112 bits by left-padding with zeros to form the SRTP Master Salt • Key Derivation Function is AES in Counter Mode • The SRTP encryption transform is the AES in Counter Mode • The Key Derivation Rate (KDR) is set to zero • MKI is used for distributing SK_RAND and included in every encrypted RTP packet • PI (ROC+ Received Seq) is used for calculating IV (Initialization Vector) • Decrypt contents by using IV and SRTP session Key (SK) Page 12
Accounting • Collected accounting data should be able to help service provider: • Billing on BCMCS Originators/Content Provider • Billing on BCMCS Viewers/Subscribers • Accounting type: • Flat fee (e.g., monthly payment) • Pay per View (BAK Lifetime based Accounting) • Octet Based Accounting • Accounting data may be collected by: • RAN (Radio Access Network) • BSN (Broadcast Serving Node) • BCMCS Controller • Accounting data should send to HAAA/SAAA. Page 13
CDMA 1x and HRPD BCMCS Radio Capabilities • Support both Idle State and Traffic State BCMCS • Support concurrent services (Simultaneous unicast and broadcast or multiple broadcast) • Page Set Maintenance (Be able to receive incoming calls and MS directed message during monitoring BCMCS) • Dynamic BCMCS (Based on User presence to decide whether transmitting the BCMCS IP flow) • Autonomous Request BCMCS flows that are not advertised by the current sector • Support autonomous soft combining and Reed Solomon code to improve performance • Registration Authorization (BAK Hash Based) • Support of scheduled program • Support of group paging Page 14
BCMCS Phase II Work Items • Over the Air Enhancement: • Add Enhanced BCMCS radio interface in HRPD: • C.S0054-A will be changed to support Enhanced BCMCS (No network impact) • File Distribution Protocol • BCMCS Codec • Network Enhancement (target by end of this year): • Open Interface between the BCMCS Controller and Content Server • Duration/Usage Based Accounting • Additional QoS Parameters Support • Network/BCMCS Controller Initiated Bearer Path Establishment • Localized Programs • BCMCS Program categories • Preview of BCMCS Programs Page 15
OMA BCAST Scope • Current OMA BCAST Scope includes: • Stream Distribution • File Distribution • Service and Content Protection • Service/Terminal Provisioning • Service Discovery and Service Guide • Notification • Interaction Function • 3GPP2 View of OMA BCAST Scope • OMA BCAST Scope should focus on Application Layer • No need to specify Network/Transport Layer • OMA BCAST should avoid overlapping work/activities with 3GPP/3GPP2 whenever possible • If overlap occurs, the mechanisms from 3GPP/3GPP2 should be adopted Page 16
Current OMA BCAST Protocol Model Page 17
Proposed OMA Protocol Stack Some OMA BCAST Functions overlap with BCMCS Functions, such as service protection, file distribution, interaction function etc. Page 18
Conclusion and Recommendation • 3GPP2 has completed BCMCS Phase I work • 3GPP2 BCMCS Phase II work is ongoing • 3GPP2 would welcome continuing communications and coordination regarding broadcast activities between OMA and 3GPP2 towards greater reuse of mechanisms and protocols and less work duplication • Specific 3GPP2 recommendations: • Service Protection should be bound to the subscription • Coordinated effort for specifying appropriate content protection mechanism • Coordinated effort for specifying appropriate File Distribution Protocol • It would be desirable for OMA BCAST and 3GPP2 to avoid overlapping work/activities wherever if possible • OMA BCAST should focus on Application Layer Enablers agnostic to underlying BDS Page 19