Charging Management

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• Charging Management
• in
• 3GPP SA5 SWGB
• What the standards provide
• Chair Karl-Heinz Nenner (T-Mobile)
• Vice Chair Gerald Görmer (Siemens AG)

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SA5 SWGB Rapporteur Group Structure
General Charging Session Karl-Heinz
Nenner (T-Mobile)
Bearer Charging Session Benni Alexander (Nokia)
IMS Charging Session Göran Andersson (Ericsson)
Service Charging Session Gerald Görmer (Siemens
AG)
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Table of contents

• 1. Motivation
• 2. Setting the scene for charging in 3GPP
• 2.1 Charging Levels
• 2.2 Charging Methods
• 3. Timeline
• 4. Release 6
• 4.1 Common Charging Architecture
• 4.2 Common Interfaces and Applications
• Additional Functionality
• 5.1 The Online Charging System
• 5.2 Flow based Bearer Charging

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MotivationThe business principles behind

• The Vendor business paradigm
• to sell equipment to Operators,
• purpose of equipment is to build telecom
  networks
• The Operator business paradigm
• build and operate a (mobile) telecom network
• purpose of network is to provide end user
  services
• The Customer
• uses and will be billed for - the end user
  services
• Charging is the central enabler for the end user
  billing
• ?there will be no equipment sold, no network
  built and no service offered unless the service
  can be billed
• ?charging is at the core of the business for
  vendors and operators alike!

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MotivationThe key terms in 3GPP

• accounting process of apportioning charges
  between the Home Environment, Serving Network and
  Subscriber.
• billing function whereby CDRs generated by the
  charging function(s) are transformed into bills
  requiring payment.
• charging a function within the
  telecommunications network and the associated
  OCS/BD components whereby information related to
  a chargeable event is collected, formatted,
  transferred and evaluated in order to make it
  possible to determine usage for which the charged
  party may be billed.
• OCS Online Charging System
• BD Billing Domain

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Setting the scene for charging in 3GPP

• Charging Levels
• Bearer, Subsystem and Service charging
• Charging Methods
• Online versus Offline charging

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Setting the sceneCharging Levels

• 1. Bearer Charging, comprising
• Charging for the Circuit Switched Domain
• Charging for the Packet Switched Domain (GPRS)
• Charging for the I-WLAN
• 2. Subsystem Charging, i.e. IMS
• 3. Service Charging, comprising
• MMS
• LCS
• More to come, e.g. MBMS, Push, Presence,
  Messaging
• In future, OMA Services ?!

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Setting the sceneCharging Methods

• offline charging
• Charging mechanism where charging
  information does not affect, in real-time, the
  service rendered. The final result of this
  charging mechanism is the forwarding of CDR files
  to the Billing Domain.
• online charging
• Charging mechanism where charging
  information can affect, in real-time, the service
  rendered and therefore a direct interaction of
  the charging mechanism with bearer/session/service
  control is required. The mechanism comprises
  the execution of credit control and subscriber
  account balance management on the Online Charging
  System.

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Setting the scene Bearer Charging CS domain

• CS domain charging involves
• the GMSC
• the MSC (server)
• the HLR
• the EIR
• Offline Charging
• CDR types for MOC, MTC, IncGW, OutGW.
• Online charging CAMEL
• TS 03.78/09.78 (GSM)
• TS 23.078 / 29.078 (3GPP)

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Setting the scene Bearer Charging CS domain

• Basic principles
• call records per call/duration
• Multiple partial records for long calls
• Tariff Time Change captured within CDR
• All service invocation information inside CDRs
• Major CS charging parameters
• Origination / Destination of call
• Invoked services (BS, TS, SS)
• Radio resource usage for data
• Special Cases
• SMS (supported from the early days)
• Mobile Originated SMS CDR
• Mobile Terminated SMS CDR
• LCS (supported as of Rel-4)
• Mobile terminated location request CDR
• Mobile originated location request CDR
• Network induced location request CDR

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Setting the scene Bearer Charging PS domain

• PS domain (GPRS) charging involves the SGSN and
  the GGSN
• Offline Charging
• M-CDR records MM items when user is GPRS attached
• S-CDR and G-CDR capture PDP context charging
• Online charging
• CAMEL based
• TS 03.78/09.78 (GSM)
• TS 23.078 / 29.078 (3GPP)
• Diameter based
• Built upon IETF DCC

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Setting the scene Bearer Charging PS domain

• Basic principles
• There is no concept of service invocation, all
  traffic is plain IP
• There is no concept of mobile termination, but
  uplink and downlink traffic instead
• CDRs are generated per user connection (PDP
  context)
• CDRs are time and volume based
• Each CDR contains one or more volume containers,
  characterised by QoS and Tariff Time
• Uplink and downlink volume counted separately
• Non-volatile storage of CDRs on the CGF
• Major GPRS charging parameters
• User ID (origination) as in CS
• APN (destination)
• Time, data volume, QoS
• Special Cases SMS and LCS as in CS domain

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Setting the scene Bearer Charging WLAN

• WLAN an interworking architecture for non-3GPP
  WLAN (i.e. 802.11) with the 3GPP core network
• In Rel-6, there are two relevant interworking
  scenarios
• Scenario 2 is a SIM based authentication/authorisa
  tion, providing IP connectivity via the WLAN
• Scenario 3 with Access to 3GPP services (IMS,
  SMS, MMS, ) on top of the above
• Charging functionality is currently being
  specified in SA5
• Will be similar to GPRS
• Will make use of IETF AAA technology (use of
  Diameter)
• Time and data volume to be counted
• in WLAN only in scenario 2 ? reported to VPLMN
• in WLAN, VPLMN AAA and HPLMN AAA in scenario 3,
  where user traffic traverses VPLMN and HPLMN

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Setting the scene Subsystem ChargingIP
Multimedia Subsystem (IMS)
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Setting the scene Subsystem ChargingIMS
Charging Generals

• Proxy Call Session Control Function (CSCF)
• Determines applicable I-CSCF
• Routes SIP signalling between UE and S-CSCF
• Resource control via embedded PCF
• Serving CSCF
• Responsible for session control
• Interacts with service platforms
• May behave as SIP proxy or user agent
• accepts requests and services them internally or
  translates / forwards them on
• may terminate and independently generate SIP
  transactions
• Interrogation CSCF
• Determines applicable S-CSCF
• Routes SIP signalling to / from foreign
  networks (Roaming)
• Application Server
• Provides any kind of service

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Setting the scene Subsystem ChargingIMS
Charging Basic principles

• ? CDRs are generated per IMS session / duration
• ? Tariff Time Change is captured within CDR
• ? All media component invocation information is
  inside the CDRs
• Each CDR contains one or more media component
  descriptors
• AS information is captured, if AS(s) is / are
  involved
• ? many similarities with CS charging, BUT
• Completely different, distributed charging
  architecture
• ACR start / stop / interim are generated per SIP
  message
• CDRs are generated by CCF and then sent to BD
• ACRs and CDRs are asynchronous
• No transport network infomation (e.g. radio
  resources)
• If correlation with GPRS CDRs required, this is
  done by cross-correlating GPRS and IMS Charging
  IDs
• Correlation between IMS CDRs is required (e.g.
  CSCF CDRs, AS CDRs) all CDRs contain the same
  IMS Charging ID

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Setting the scene Subsystem ChargingIMS
Charging Aspects

• Major IMS charging parameters
• Origination / Destination of session
• Invoked media components (audio, video, etc.)
• AS information, if applicable
• Offline Charging with 7 CDR types 1 each per IMS
  node type
• P-CSCF captures session related information
• S-CSCF captures similar information as the
  P-CSCF, but
• only S-CSCF CDR has AS related information
• only P-CSCF CDR has information on authorised QoS
  
• I-CSCF captures user registration events
• AS captures service invocation information
• Others (more details in special cases below)
• interworking with CS services
• Conferencing
• Online charging only in S-CSCF, AS and MRFC

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Setting the scene Subsystem ChargingIMS
Charging Special cases

• SIP Events create ACR Events instead of
  start/interim/stop messages
• SIP NOTIFY
• SIP MESSAGE
• SIP REGISTER
• SIP SUBSCRIBE
• SIP Final Response indicating an unsuccessful SIP
  session set-up
• SIP Final Response indicating an unsuccessful
  session-unrelated procedure
• SIP CANCEL, indicating abortion of a SIP session
  set-up
• I-CSCF completing a HSS Query that was issued for
  a SIP INVITE
• AS service invocation events
• CS interworking
• Several nodes support CS interworking, i.e. MGCF,
  MGW, BGCF
• MGCF and BGCF can generate call related CDRs
• Conferencing
• MRFC and MRFP provide conferencing capabilities
  (H.248)
• MRFC can generate related CDRs

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Setting the scene Service ChargingMultimedia
Messaging Service (MMS)
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Setting the scene Service ChargingMMS
Charging Generals

• ? Multimedia Messaging Service (MMS) is based on
  a specific service node called the MMS Relay /
  Server (MMS R/S)
• ? Originator MMS R/S serves the MM originator
• ? Recipient MMS R/S serves the MM recipient
• ? Inter-MMS R/S traffic uses SMTP (email)
• ? Differences to SMS
• Only one MMS R/S involved for intra-PLMN MM
  transfer, e.g. T-D1 to T-D1
• 2 MMS R/S involved if originator and recipient
  are subscribed to different networks (e.g. T-D1
  to Vodafone)
• In SMS, only one SMSC is involved
• In contrast to SMS, MMS charging is standardised
  in the service area (i.e. the MMS R/S), not the
  bearer domain (MSC/SGSN)

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Setting the scene Service ChargingMMS
Charging Basic principles

• ? The MMS R/S collects charging information such
  as
• destination / source addresses used by the User
  Agent (UA)
• identification of the MMS R/S(s) involved in the
  MM transaction
• the size of the MM and its components
• storage duration, i.e. the time interval when a
  MM is saved on a non-volatile memory media
• identification of the bearer resources used for
  the transport of the MM, i.e. the identity of the
  network and the network nodes
• In scenarios involving a VASP, the charging
  information describes the identification of the
  VASP and the amount of user data sent and
  received between the MMS R/S and the VASP.
• ? The information listed above is captured for
  use cases in relation to
• MM submission, retrieval and forwarding
• transactions involving the MMbox
• transactions involving a VASP

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Setting the scene Service ChargingMMS
Charging Aspects

• Major charging parameters
• Originator and Recipient (user agent network)
• MM volume (size)
• Offline Charging
• MM1 CDR types to enable end user billing
• MM submission, retrieval and forwarding
• Read reply, delivery report, notification,
  deletion
• Upload, download, removal from / to MMBox
• MM4 CDR types intended for inter-network
  accounting
• MM exchange between MMS R/S in different networks
• Read-reply and delivery reports
• MM7 CDR types for VASP transactions
• Submission and cancellation
• Read-reply, delivery reports
• Online Charging with Diameter Credit Control

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Setting the scene Service ChargingLoCation
Service (LCS)
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Setting the scene Service ChargingLCS
Charging Generals

• Charging information in the Service domain (GMLC)
  is collected for inter-operator accounting
  purposes a network requesting location info may
  be charged by the network providing the location
  info
• The main charging parameters collected by the
  GMLCs are
• Identity of the mobile subscriber to be located
• Identity of the entity requesting the location
• Identity of the GMLC or PLMN serving the LCS
  client
• the quality of the location requested by /
  delivered to the client
• date / time the location procedure was requested
  by the client
• Usage of continuous/periodic tracking
• LBS information, describing the service specific
  parameters in addition to the above location
  resource information
• The information listed above is captured for all
  BC use cases
• Mobile Originated Location Request
• Mobile Terminated Location Request
• Network Induced Location Request

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Timeline of charging TS

• Bearer, Subsystem and Service charging Releases
• Online Offline charging

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Timeline of charging TSCS and PS domains

• ? CS Offline Charging
• TS 12.05 (GSM until Rel-98)
• TS 32.005 (3GPP Rel-99)
• TS 32.205 (3GPP Rel 4/5)
• TS 32.250 (3GPP Rel-6)
• ? PS Offline Charging
• TS 12.15 (GSM Rel-97/98)
• TS 32.015 (3GPP Rel-99)
• TS 32.215 (3GPP Rel 4/5)
• TS 32.251 (3GPP Rel-6)

• CS PS Online charging
• CAMEL
• TS 03.78/09.78 (GSM)
• TS 23.078 / 29.078 (3GPP)
• PS Online Charging
• based on IETF DCC
• TS 32.251 (Rel-6)

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Timeline of charging TS IMS and Service Charging

• IMS Offline Online Charging
• TS 32.225 (3GPP Rel-4/5) -gt TS 32.260 (3GPP
  Rel-6)
• S-CSCF uses ISC interface for online charging
• MMS Offline Charging
• TS 32.235 (3GPP Rel-4/5) -gt TS 32.270 (3GPP
  Rel-6)
• Online Charging
• TS 32.270 (3GPP Rel-6)
• LCS Offline Online Charging
• TS 32.271 (3GPP Rel-6)
• As a major change, Rel-6 sees the introduction
  of common charging architecture, interfaces and
  applications for all 3GPP charging

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3GPP Release 6

• Common Charging Architecture
• Common Interfaces and Applications

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Charging Standards Rel-6Getting more organised

• ? Every new technology came with its own charging
  solution
• Each domain was done independently
• Each domain has its own functional description
  and interfaces
• ? Result Too many different architectures and
  solutions
• However
• ? From an abstract viewpoint, its always the
  same functionality, regardless of system /
  technology
• Chargeable / billable items (events)
• Calls / Sessions
• Service Events
• The same basic tasks
• Collect charging relevant information (usually
  from signalling parameters)
• Create CDRs / perform online credit control
• Forward CDRs to billing domain
• Identical information flow from network to
  Billing Domain / OCS according to the above basic
  tasks

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Charging Standards Rel-6Charging Architecture
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Charging Standards Rel-6 Common offline charging
architecture
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Charging Standards Rel-6 Common offline charging
architecture

• Charging Trigger Function
• Collects Metrics from the core system, based on
  system specific triggers (e.g. signalling events)
• Formats these metrics into charging events
• forwards charging events to the CDF via Rf
  reference point
• Charging Data Function
• Collects charging events and formats them into
  CDRs according to system specific rules
• Forwards CDRs to CGF via Ga reference point
• Charging Gateway Function
• Provides non-volatile CDR file store
• Uses Bx reference point for CDR file transfer to
  Billing Domain
• Billing domain
• Receives CDR files from CGF
• No further standardisation

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Charging Standards Rel-6 Common online charging
architecture
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Charging Standards Rel-6 Common online charging
architecture

• Common approach for online charging
• Same Diameter based interface (IETF Diameter CCA)
• Same source collection (building on CTF)
• CS and GPRS will retain CAMEL
• GPRS will also see the addition of the Diameter
  interface to GGSN same as WLAN
• All new Rel-6 services (MBMS, Push, Presence,
  Messaging, ) will use same offline and online
  charging functions

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Charging Standards Rel-6Structure of TS series
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Charging Standards Rel-6Structure of TS series

• ? TS 32.240 Architecture and Principles
• Common online and offline charging architecture
• General principles of Charging
• ? One Middle Tier TS per domain / subsystem /
  service
• Mapping of common architecture onto specific
  domain
• Domain / subsystem / service specific charging
  functionality, especially type and content of
  CDRs and ACRs
• ? Common interfaces and applications between the
  entities of the common architecture
• Rf and Ro Diameter application (TS 32.299)
• Bx interface to Billing Domain (TS 32.297)
• Ga interface between CDF and CGF (TS 32.295)
• CDR Parameter and ASN.1 Syntax Description (TS
  32.298)
• ? Special case Online Charging System (OCS) (TS
  32.296)

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Additional functionality

• The Online Charging System
• Flow based Bearer Charging

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The Online Charging System
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The Online Charging System

• The following components of an OCS have been
  identified
• Charging functions for
• Session based charging
• Event based charging
• Account Balance Management Function (ABMF)
• Holds subscriber account
• Controls addition / deduction of monetary amounts
  from account
• Performs credit reservation on the account
• Management of counters applicable for the account
• Rating Function (RF)
• unit determination calculation of a number of
  non-monetary units (service units, data volume,
  time and events)
• price determination calculation of monetary
  units (price) for a given number of non-monetary
  units
• tariff determination determination of tariff
  information based on the subscribers contractual
  terms and service being requested
• Management of counters applicable for rating

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The Online Charging SystemTS 32.296 OCS
applications and interfaces

• ? Confined to Re (Rating) interface in Rel-6
• ? Two approaches are being standardised
• Rating engine model (Class A)
• Charging function fetches data from the Account
  Balance Management Function
• Charging function issues rating request towards
  the Rating Function
• Charging function triggers counter / account
  update on the Account Balance Management Function
• Design goal allow common Rating Function for
  online offline charging
• Extended rating engine model (Class B)
• Similar to the above, but the rating function
  also stores and manages some of the counters
  needed for the rate calculation
• Requires additional scenario on Re to acknowledge
  service delivery and counter update

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Flow based Bearer ChargingProblem Statement

• The problem
• Charging for bearer resources does not take into
  account the value of services accessed via these
  bearer resources
• Integrated service pricing when the tariff model
  calls for subscribers paying for the service
  (e.g. MMS), the charges for bearer usage must be
  removed
• Due to different bearer charges in roaming and
  non-roaming cases, the service price must depend
  on whether the customer is on the HPLMN or
  roaming on a foreign network
• The solution
• Make bearer charging service aware
• Make service charging access aware
• Make bearer and service charging roaming aware

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Flow based Bearer ChargingFunctionality

• Differentiate between different service data
  flows for the purpose of charging, e.g.
• Web browsing
• IP Video Telephony
• MMS versus WAP traffic
• .
• Applicable to GPRS (GGSN TS 32.251) and WLAN
  (PDG) charging
• Charging rules for online / offline charging are
  predefined or provided from a CRF (TS 29.210)
• Charging rules determine the CDR generation
  (offline charging) and credit control procedure
  (online charging)

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• Backup

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Service Based Local Policy (SBLP) Introduction

• SBLP was defined in Rel-5 to enable the IMS to
  control the QoS provided by the GPRS bearer
  service based on the requirements of the
  negotiated application services.
• This is based on particular interest if the
  bearer uses a high QoS and/or if an operator uses
  IMS network entities to charge application
  services.
• In Rel-6 the concept was extended for non-IMS
  application functions.

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Service Based Local Policy (SBLP) Architecture
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Service Based Local Policy (SBLP) Functions

• Policy Enforcement Point (PEP)
• Policy Decision Function (PDF)
• Application Function (AF)