Charging in IMS IMS charging and billing Two models: Offline Online Offline Charging info collected after termination of a session Monthly invoicing Online IMS components interwork on-line with a charging system Charging system interacts in real time with user’s account 3GPP TR 23.815 (Charging implications of IMS architecture) Charging in IMS IMS – off-line charging Home(B) = Visited(B) Home(A) = Visited(A) AS AS BS AS AS BS MRFC MRFC Bi MRFC MRFC Bi S-CSCF S-CSCF I-CSCF I-CSCF I-CSCF I-CSCF P-CSCF P-CSCF P-CSCF P-CSCF BGCF BGCF BGCF BGCF MGCF BGCF MGCF BGCF GGSN GGSN GGSN GGSN SGSN SGSN CCF S-CSCF S-CSCF SGSN SGSN Rf (Diameter) Rf CCF ACR Bp CGF Ga All componets involved in SIP session control can generate off line charging data CGF Ga Bp IMS offline charging architecture Entities CCF: Charging Collection Function CGF: Charging Gateway Function BS: Billing System Interface Rf : to send accounting information to a CCF Ga :to send accounting information to a CGF Bi : to send accounting information to a BS Bp :to send accounting information to a BS Originating Visited Network IMS Terminal GGSN PCRF Originating Home Network P-CSCF (1) INVITE CDF S-CSCF (2) INVITE P-Charging-Vector (5) 183 Session Progress P-Charging-Vector CDF (3) INVITE P-Charging-Vector (4) 183 Session Progress P-Charging-Vector (6) AAR (7) AAA (8) 183 Session Progress (9) RAR (10) RAA (11) PRACK (18) PRACK (12) PDP (19) PRACK (13) PDP (14) CCR (15) CCA (16) RAR (20) 200 OK (17) RAA (21) 200 OK (22) 200 OK (23) UPDATE (24) UPDATE (25) UPDATE (26) 200 OK (27) 200 OK (28) 200 OK (29) 200 OK (30) 200 OK (35) 200 OK (31) ACR [Start] (33) ACR [Start] (32) ACA (34) ACA (36) ACK (37) ACK (38) ACK Session establishment flow From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd IMS online charging architecture Online Charging S-CSCF SCF SCF looks like any other AS to the S-CSCF SCF dose not provide services for user in the usual sense SCF reports accounting information to the Correlation Function If the user runs out of credit CF informs the SCF SCF terminates the session by acting as a B2BUA Online Charging AS and the MRFC ECF AS or the MRFC receives the address of the ECF from the SCSCF in the P-Charging-Function-Address header field Online Charging Ro interface Is based on Diameter Accounting-Request and Answer (ACR,ACA) IEC Immediate Event Charging Accounting-Record-Type: EVENT_RECORD ECUR Event Charging with Unit Reservation Accounting-Record-Type: START_RECORD, INTERIM_RECORD, STOP_RECORD Originating Visited Network IMS Terminal Originating Home Network P-CSCF S-CSCF PS (1) PUBLISH (2) PUBLISH Evaluation of initial filter criteria (3) PUBLISH (4) 200 OK (5) 200 OK (6) 200 OK The IMS terminal publishing presence information From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd Originating Visited Network IMS Terminal P-CSCF Originating Home Network Aggregation Proxy PS/Presence XDMS S-CSCF (1) SUBSCRIBE (2) SUBSCRIBE Evaluation of initial filter criteria (3) SUBSCRIBE (4) 200 OK (5) 200 OK (6) 200 OK (7) NOTIFY (8) NOTIFY (9) NOTIFY (10) 200 OK (11) 200 OK (12) 200 OK (13) SUBSCRIBE Authorization needed Subscription in ‘pending’ state (14) 202 Accepted (15) NOTIFY (pending) (16) 200 OK (17) NOTIFY (18) NOTIFY (19) NOTIFY (20) 200 OK (21) 200 OK (22) 200 OK (23) HTTP PUT (24) HTTP PUT (25) 200 OK (26) 200 OK (27) NOTIFY (active) (28) 200 OK Subscription to own Watcher Information From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd Presence Optimizations Optimizations High Notification Rates Event throttling Presence Optimizations Partial Notification Event Notification Filtering The IMS networks and terminals implement all the extensions The Ut Interface Runs between an IMS terminal and an Application Server The Ut interface is implemented with HTTP XML Configuration Access Protocol (XCAP) Pager mode IM in IMS 3GPP TS 24.229 standard requires IMS terminals to implement MESSAGE method RFC 3428 Optional service feature in S-CSCF and AS Constraints eg Message size Main goal Enabling S-CSCF or AS to send instant messages to IMS terminals Example AS performs role of a controller in a voice mail service Notification of the user by AS about waiting messages Implementation Registration S-CSCF analyzes iFC S-CSCF sends 3rd party REGISTER message to a selected AS After reception of the REGISTER request, the AS generates MESSAGE request with notification (text info, link, ….) MESSAGE transferred via S-CSCF and P-CSCF as each SIP message Originating Visited Network IMS Terminal #1 Originating Home Network P-CSCF S-CSCF Terminating Visited Network Terminating Home Network I-CSCF HSS S-CSCF P-CSCF IMS Terminal #2 (1) MESSAGE (2) MESSAGE Evaluation of initial filter criteria (3) MESSAGE (4) Diameter LIR (5) Diameter LIA (6) MESSAGE Evaluation of initial filter criteria (7) MESSAGE (8) MESSAGE (9) 200 OK (10) 200 OK (11) 200 OK (12) 200 OK (13) 200 OK (14) 200 OK Pager-mode instant messaging in the IMS From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd Alert user IMS Terminal P-CSCF I-CSCF HSS S-CSCF AS (1) REGISTER (2) REGISTER (3) Diameter UAR (4) Diameter UAA (5) REGISTER (6) Diameter MAR (7) Diameter MAA (8) 401 Unauthorized (9) 401 Unauthorized (10) 401 Unauthorized (11) REGISTER (12) REGISTER (13) Diameter UAR (14) Diameter UAA (15) REGISTER (16) Diameter SAR (17) Diameter SAA (18) 200 OK (19) 200 OK Evaluation of initial filter criteria (20) 200 OK (21) REGISTER (22) 200 OK (23) MESSAGE (24) MESSAGE (25) MESSAGE (26) 200 OK (27) 200 OK (28) 200 OK Example of a service provided with pager-mode instant messages From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd IM session model Instant messaging session initiated by INVITE with SDP media definition for IM Message Session Relay Protocol (MSRP) for transport of messages Two scenarios Terminal IMS establishes a session SIP messages transferred via IMS nodes MRFC i MRFP act as middlemen Charging based on message size or content (MRSP SEND) MRF as „chat room” server – multiparty conference MRSP: VISIT, OK, SEND Later the second user joins the conference and establishes the second session with MRFC Originating Visited Network Originating Home Network P-CSCF S-CSCF IMS Terminal #1 (1) INVITE (2) 100 Trying Terminating Visited Network Terminating Home Network I-CSCF HSS S-CSCF P-CSCF IMS Terminal #2 (3) INVITE (4) 100 Trying Evaluation of initial filter criteria (5) INVITE (6) 100 Trying (7) Diameter LIR (8) Diameter LIA (9) INVITE (10) 100 Trying Evaluation of initial filter criteria (11) INVITE (12) 100 Trying (13) INVITE (14) 100 Trying (20) 180 Ringing (18) 180 Ringing (19) 180 Ringing (17) 180 Ringing (16) 180 Ringing (15) 180 Ringing (21) 200 OK (22) 200 OK (23) 200 OK (24) 200 OK (25) 200 OK (26) 200 OK (27) ACK (28) ACK (29) ACK (30) ACK (31) ACK (32) MSRP: SEND (33) MSRP: 200 OK (34) MSRP: SEND (35) MSRP: 200 OK Session-based instant messages: end-to-end MSRP session From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd Alert user Accept session Originating Visited Network IMS Terminal #1 P-CSCF (1) INVITE (2) 100 Trying Originating Visited Network Originating Home Network S-CSCF MRFC MRFP S-CSCF P-CSCF IMS Terminal #2 (3) INVITE (4) 100 Trying Evaluation of initial filter criteria (5) INVITE (6) 100 Trying (7) H.248 (8) 200 OK (9) 200 OK (10) 200 OK (11) ACK (12) ACK (13) ACK (16) INVITE (18) INVITE (14) MSRP: SEND (19) 100 Trying (15) MSRP: 200 OK (17) 100 Trying Evaluation of initial filter criteria (20) INVITE (21) 100 Trying (22) H.248 (23) 200 OK (24) 200 OK (25) 200 OK (26) ACK (27) ACK (28) ACK (29) MSRP: SEND (30) MSRP: 200 OK (31) MSRP: SEND (33) MSRP: SEND (32) MSRP: 200 OK (34) MSRP: 200 OK A multi-party session-based conference (chat server) From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd Conferencing in IMS Conferencing services in IMS 3GPP standard - TS 24.147 based on SIPPING RFC 4353 XCON RFC 4582 elements utilized BFCP (Binary Floor Control Protocol) Centralized conference server model „Tightly coupled conference” model Logical distribution of the server into components Signaling Media PSTN interworking Access for PSTN users via MGCF acting as a conference participant SIP for communication with AS/MRFC AS / MRFC Mp MRFP Conference Server The IMS conference service architecture From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons , Ltd Alice Conference Server Bob (1) INVITE Conference Factory URI (2) 200 OK Contact: Conference URI (3) ACK (4) INVITE Conference URI (5) 200 OK Contact: Conference URI (6) ACK Conference creation using a conference factory URI From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd Originating Visited Network Originating Home Network P-CSCF S-CSCF IMS Terminal (1) INVITE (2) 100 Trying Terminating Home Network I-CSCF HSS AS/MRFC (3) INVITE (4) 100 Trying Evaluation of initial filter criteria (5) INVITE (6) 100 Trying (7) PSI Location Query (8) Response (9) INVITE (10) 100 Trying Interaction with MRFP to allocate resources for the conference (14) 183 Session Progress (13) 183 Session Progress (12) 183 Session Progress (11) 183 Sesssion Progress Joining a conference identified by a PSI From The 3G IP Multimedia Subsystem (IMS), Third Edition Gonzalo Camarillo and Miguel A García-Martín © 2008 John Wiley and Sons, Ltd