Rc (TS 132.296) and Sy (TS 29.219) Interface Session #2 Author: Victor I. Fajardo Date: Sept. 27, 2013 Diameter Session #2

Agenda Overview of the OCS (On-line Charging system) Online vs. Offline charging Functional requirements Service consumption rating Account balance management Charging transaction control Charge support Correlation function Diameter Session #2

Agenda The Sy Interface The Rc Interface Policy Enforcement Overview Spending Limit report (Request, Notification and Cancelation) Protocol Details Message Formats Message Flows The Rc Interface Account Balance Management Overview Debit operation Account reservation Refund Balance Query Diameter Session #2

OCS Overview (Architecture) Diameter Session #2

Online vs. Off-line Charging Offline charging is applied to users who pay for their services periodically (e.g., at the end of the month) Online charging (credit-based charging) is used for prepaid services Real-time credit control Both real-time and prepaid maybe applied to the same session Charging function addresses Addresses distributed to each IMS entities and provide a common location for each entity to send charging information Charging Data Function (CDF) addresses are used for offline billing and Online Charging Function (OCF) for online billing. Diameter Session #2

Offline Charging SIP network entities (P-CSCF, I-CSCF, S-CSCF, BGCF, MRFC, MGCF, AS) involved in the session uses Rf to send accounting information to a CDF CDF will collect all this information, and build a Call Detail Record (CDR), which is sent to the billing system (BS) of the domain Each session carries an IMS Charging Identifier (ICID) as a unique identifier generated by the first IMS entity involved in a SIP transaction and used for the correlation with CDRs Each domain has its own charging network Billing systems in different domains will also exchange information, so that roaming can be applied Diameter Session #2

Online Charging The S-CSCF talks to a Session Charging Function (SCF) which looks like a regular SIP application server The SCF can signal the S-CSCF to terminate the session when the user runs out of credits during a session The AS (Application Server) use the Ro interface to the Online charging function Immediate Event Charging (IEC) The number of credit units is immediately deducted from the user's account AS is then authorized to provide the service. The service is not authorized when not enough credit units are available Charging with Unit Reservation (ECUR) The number of credit units in the user's account is reserved. AS is then authorizes After the service is over, the number of spent credit units is reported and deducted from the account; the reserved credit units are then cleared Diameter Session #2

OCS Functions Event Based Charging Function On the bearer level It controls the bearer usage in the network, e.g. SMS On the subsystem level It controls the resource availability in network, e.g. it has the ability to grant or deny the resource usage On the service level it has the ability to grant or deny the service usage in the network Session Based Charging Function It controls the bearer usage in the network, e.g. in terms of time or volume granted Grant or deny a session setup request and to terminate an existing session It controls service availability in the network, e.g. it has the ability to grant or deny a usage of a service Diameter Session #2

OCS Rating Functions Rating for network- and external services and applications (session, service, event) before and after service delivery; Cross-product and cross-channel discounts, benefits and allowances. The Rating Function must be able to handle a wide variety of rateable instances, such as: Rating of volume (in terms of granted units or money, e.g. based on charging initiated by an access network entity); Rating of time (in terms of granted units or money, e.g. based on charging initiated by a SIP application); Rating of events (e.g. based on charging of web content or MMS) Diameter Session #2

The Sy Interface The Sy reference point is located between the Policy and Charging Rules Function (PCRF) and the OCS Enables transfer of policy counter status information relating to subscriber spending from OCS to PCRF Request of policy counter status reporting from PCRF to OCS and subscribe to or unsubscribe from spending limit reports (i.e. notifications of policy counter status changes). Notification of spending limit reports from OCS to PCRF. Cancellation of spending limit reporting from PCRF to OCS Diameter Session #2

Diameter Session #2

Sy Spending Limit Request and Answer Commands Diameter Session #2

Sy Spending Status Notification Request and Answer Commands Diameter Session #2

Sy Specific Diameter AVPs Description Policy-Counter-Identifier Uniquely identifies a policy counter that is maintained per subscriber within the OCS Policy-Counter-Status Identifies the policy counter status applicable for a specific policy counter and subscriber Policy-Counter-Status-Report Report the status of a specific policy counter SL-Request-Type Informs the OCS whether the SLR command is being sent as part of the initial or intermediate spending limit report request procedure Pending-Policy-Counter-Information Contains the pending policy counter status and the active time Pending-Policy-Counter-Change-Time Indicates the NTP time at which the pending policy counter becomes the current status of a policy counter Diameter Session #2

Sy Initial/Intermediate Report Message Flows H-PCRF OCS 1. Policy decision depends on spending info 2. Diameter SLR 3. Diameter SLA Diameter Session #2

Sy Initial/Intermediate Reports Request AVPs Element Diameter AVP Description User Identity Subscription-Id Contain the identity of the user. It shall be present in the initial request when the SL-Request-Type=INITIAL_REQUEST Request Type SL-Request-Type Indicate whether this is the initial or a subsequent request for the user Subscribed Policy Counter Identifier List Policy-Counter- Identifier Indicate the list of policy counter identifiers to be subscribed to. In the intermediate spending limit report request procedure, this list overrides a previously provisioned list. If omitted in either the Initial or Intermediate Spending Limit Report Request procedures the PCRF requests subscription to all available policy counters. Diameter Session #2

Sy Initial/Intermediate Reports Response AVPs Element Diameter AVP Description Policy Counter Status Report Policy-Counter- Status-Report If present, this information element shall contain a policy counter identifier, the current status value and/or pending policy counter statuses with the activation times Result Result-Code Contain the result of the operation Diameter Session #2

Sy Intermediate Spending Limit Report Message Flows H-PCRF OCS 1. Additional or fewer policy counters are determined to be relevant for policy decision 2. Diameter SLR 3. Diameter SLA 4. Policy decision depends on spending info Diameter Session #2

Sy Spending Limit Report Request Element Diameter AVP Description Policy Counter Status Report Policy-Counter- Status-Report If present, this information element shall contain a policy counter identifier, the current status value and/or pending policy counter statuses with the activation times Sy Spending Limit Report Response Element Diameter AVP Description Result Result-Code Contain the result of the operation Diameter Session #2

Sy Final Spending Limit Report Message Flows H-PCRF OCS 1. Decision to unsubscribe to changes in the Policy-Counter-Status 2. Diameter STR 3. Diameter STA Diameter Session #2

Sy Spending Limit Report (Status Change) Message Flows H-PCRF OCS 1. Policy-Counter-Status change (e.g. Threshold reached) 2. Diameter SNR 3. Diameter SNA Diameter Session #2

Sy Final Spending Limit Report Request Element Diameter AVP Description Termination Cause Termination- Cause This IE shall contain the reason why the session was terminated. It shall be set to "DIAMETER_LOGOUT” Sy Final Spending Limit Report Response Element Diameter AVP Description Result Result-Code Contain the result of the operation Diameter Session #2

The Rc Interface The Rc reference point is located between the OCF (Online Charging Function) and ABMF (Account Balance Management Function) ABMF manages subscribers credits Supports query, credit, debit, refunds etc. Rc allows the OCS to perform: Immediate account debit operation Event based account reservation debit/release operation Session based account reservation debit/release operation Account refund Account balance query Diameter Session #2

Rc Credit-Control Request and Answer Commands Diameter Session #2

Rc Event Description Event Description Immediate Account Debit The credit control process for events is controlled by the Credit- Control-Request (CCR) with corresponding CC-Requested-Type EVENT_REQUEST Event based Account Debit with Reservation Event Charging with Unit Reservation is used for credit control sessions and uses the Credit-Control-Request (CCR) with CC- Request-Type INITIAL and TERMINATION_REQUEST Session based Account Debit with Reservation Session Charging with Unit Reservation is used for credit control sessions and uses the Credit-Control-Request (CCR) with CC- Request-Type INITIAL / UPDATE and TERMINATION_REQUEST Account Refund Credit-Control-Request (CCR) with CC-Request-Type AVP set to EVENT_REQUEST to refund monetary units to the subscriber"s account. The Requested-Action AVP (RA) is set to REFUND_ACCOUNT Account Balance Query Credit-Control-Request (CCR) with CC-Request-Type AVP set to EVENT_REQUEST to query the subscriber"s account. The Requested-Action AVP (RA) is set to BALANCE_CHECK Diameter Session #2

Rc Specific Diameter AVPs Description AB-Response Contains information related to present information and counters information which stored in the ABMF Acct-Balance Contains information related to return specific account balance when a subscriber has multiple accounts. A subscriber may have multiple accounts assigned by operator, e.g. normal account, present account, etc. Acct-Balance-Id Uniquely identifies the account balance within the ABMF Diameter Session #2

Rc Immediate Account Debit Message Flows Diameter Session #2

Rc Event based Account Reservation with Debit or Release Message Flows Diameter Session #2

Rc Session based Account Reservation with Debit or Release Message Flows Diameter Session #2

Rc Account Refund Message Flows Diameter Session #2

Rc Balance Message Flows Diameter Session #2

Questions ? Diameter Session #2