Description
CSI GPRS, formally known as CAMEL Subscription Information for GPRS, is a critical component of the Customised Applications for Mobile networks Enhanced Logic (CAMEL) framework applied to packet-switched services. It is not the GPRS core network itself, but rather the subscription data and associated triggers that enable CAMEL-based service control for a subscriber's GPRS sessions. This information is stored as part of the subscriber's profile in the Home Location Register (HLR) or Home Subscriber Server (HSS) and is downloaded to the Serving GPRS Support Node (SGSN) when the subscriber attaches to the network.
The CSI GPRS data includes specific Detection Points (DPs) that act as triggers during a Packet Data Protocol (PDP) context activation or modification procedure. When the SGSN encounters a configured DP (e.g., DP PDP Context Establishment), it suspends the normal procedure and sends a CAMEL Application Part (CAP) message to a designated GSM Service Control Point (gsmSCP). This gsmSCP, which hosts the operator's intelligent service logic, can then influence the session in real-time. Based on its logic, the gsmSCP can instruct the SGSN to allow, deny, or modify the PDP context request. It can also apply specific charging instructions, such as connecting the data session to a CAMEL-based online charging system for real-time credit control, or apply gating functions to control which IP flows are permitted.
This mechanism allows for sophisticated, subscriber-specific handling of data services. For example, it can be used to implement prepaid data plans, where the gsmSCP monitors data volume in real-time and can terminate the session when credit is exhausted. It can enable sponsored data services, where traffic to specific Application Servers (APNs) is zero-rated. It also allows for service-aware policies, such as applying different QoS profiles or routing for different applications initiated by the same subscriber. The SGSN acts as the CAMEL Service Switching Function (gsmSSF) for GPRS, interfacing with the gsmSCP to execute this external control.
Purpose & Motivation
CSI GPRS was developed to extend the intelligent network (IN) capabilities of CAMEL, originally designed for circuit-switched voice calls, into the packet-switched domain of GPRS and later 3G/4G data services. Before its introduction, control and charging for data sessions were relatively static, based on subscription profiles in the HLR and local policies in the SGSN/Gateway GPRS Support Node (GGSN). This lacked the flexibility for real-time, interactive service control required for innovative data offerings like prepaid internet, content-based charging, and partner service integration.
Its creation was motivated by the commercial need for operators to deploy advanced, customizable data services that could be controlled dynamically from a central service logic platform. It solved the problem of applying complex, stateful service logic (like spending limit checks, time-of-day allowances, or application-specific policies) to inherently stateless IP data flows. By leveraging the established CAMEL architecture, it provided a standardized, vendor-interoperable way to introduce intelligent control, enabling new business models for mobile data in the 2.5G and 3G eras. It formed the basis for later Policy and Charging Control (PCC) architectures, bridging the gap between traditional IN and all-IP networks.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (91 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the enhancements to the GPRS function for CAMEL Subscription Information (CSI) primarily focused on improving location information reporting. This included updates to accommodate new 5GS and NG-RAN cell identities, support for a 3-byte TAC, and enhanced reporting for WLAN access, cell site information, and handover details. Furthermore, the release introduced the delivery of PTC encryption information and added reporting for media bearer information and rate-control triggers.
- Enhance Location Information object for NG-RAN Cell Identity TS 31.111CR0673
- Enhance Location Information object to accommodate 3 byte TAC for 5GS. TS 31.111CR0691
- Enhance location information in trusted and untrusted WLAN TS 32.251CR0503
- Enhance location information in trusted and untrusted WLAN TS 32.298CR0658
- Adding of the abbreviations and Network Function Architecture for Cell site Information reporting plus Handover details TS 33.107CR0276
- PTC Encryption information delivery TS 33.107CR0297
+ 16 more changes
In Release 16, the CSI GPRS function was enhanced to support new service information reporting, including VoLTE information and 5WWC (5G Wireline-Wireless Convergence) charging data. The function was also updated to carry Presence Reporting Area information during mobility events like S1 handover and to include V2X information within the UE context. Furthermore, charging detail records (CDRs) were extended to incorporate Rate-Control information and corresponding triggers.
- PROVIDE LOCAL INFORMATION to get Slice(s) information TS 31.111CR0730
- Add VoLTE information TS 32.251CR0516
- Add VoLTE information TS 32.298CR0784
- Add 5WWC charging information TS 32.298CR0814
- Introduction of NSM charging information TS 32.298CR0820
- Correction of SubscriptionID usage TS 32.298CR0855
+ 12 more changes
In Release 17, the GPRS CAMEL Subscription Information (CSI) function was enhanced to include the procedure for a REFRESH command triggered by an update of disaster roaming information. Furthermore, the Location Information object was enhanced to accommodate a complete TAI list along with the current TAI for Satellite E-UTRAN and Satellite NG-RAN, and GERAN/UTRAN user location information was added. These updates provided more comprehensive location data and new triggers for subscription information refresh.
- PLI - slice information during no service or limited service state. TS 31.111CR0753
- Addition of procedure for REFRESH command triggered by update of disaster roaming information TS 31.111CR0766
- Enhance Location Information object to accommodate complete TAI list along with current TAI for Satellite E-UTRAN and Satellite NG-RAN. TS 31.111CR0776
- Add GERAN/UTRAN user location information TS 32.298CR0874
- Addition of new URLLC information element TS 32.298CR0876
- Additional charging information for the 5G LAN charging TS 32.298CR0889
+ 7 more changes
In Release 18, the GPRS CAMEL Subscription Information (CSI) function was enhanced to provide more detailed network slice information to applications. Specifically, new capabilities were introduced for the **PROVIDE LOCAL INFORMATION** procedure to report both active and rejected slices, including their S-NSSAI mappings and status change events. Additionally, the release added support for converged charging information and updated parameters for CAG (Closed Access Group) cell selection events.
- PROVIDE LOCAL INFORMATION to get Slices information with S-NSSAI mapping TS 31.111CR0792
- PROVIDE LOCAL INFORMATION (Rejected Slices information) introduction and simplification of PROVIDE LOCAL INFORMATION (Slices information) TS 31.111CR0802
- Required Rel 18 update to PLI - Slice Information, and Slice status change event TS 31.111CR0811
- Addition of converged charging information TS 32.270CR0034
- Addition of MMS converged charging information TS 32.298CR0920
- Rel-18 CR 32.298 Add TSN specific charging information to CDR TS 32.298CR0978
+ 12 more changes
In Release 19, the enhancements for the GPRS CAMEL Subscription Information (CSI) function primarily introduced new charging information capabilities. These include specific support for store-and-forward satellite operations for both SMS and User Plane CIoT services, as well as converged charging for Ranging and Sidelink Positioning procedures. Furthermore, the release added charging information related to network slice energy consumption and extended Location Service (LCS) charging bindings for 5G systems.
- Support of Time Reference Information Distribution Indication TS 29.274CR2113
- DNN association for served S-NSSAI in Terminal Response for PLI - list of slices information and Envelope (Event Download slice status) command TS 31.111CR0871
- Rel-19 CR 32.240 Support the energy related information per network slice TS 32.240CR0498
- Add charging information for store and forward satellite operation of SMS service TS 32.251CR0521
- Add charging information for store and forward satellite operation with UP CIoT TS 32.251CR0523
- Introduction of converged charging information for Ranging and Sidelink Positioning TS 32.271CR0026
+ 14 more changes
Explore further
Broader topics and technologies where GPRS plays a role.
Defining Specifications
3GPP specifications that define or reference GPRS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 03.071 v7b0 | Location Services (LCS) Stage 2 Description | Rel-7 |
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TR 21.978 v1300 | CAMEL Control of VoIP Services Feasibility Study | Rel-4 |
| TS 22.060 vj00 | GPRS Stage 1 Service Description | Rel-19 |
| TS 22.100 v1320 | UMTS Service Requirements Phase 1 | Rel-4 |
| TS 22.112 v1800 | USAT Gateway System Specification | Rel-8 |
| TS 22.228 vj00 | IP Multimedia Service Requirements | Rel-19 |
| TS 22.234 vd10 | 3GPP-WLAN Interworking Index Specification | Rel-13 |
| TR 22.945 v1300 | Fax Services Guidance for GSM/UMTS | Rel-4 |
| TS 23.018 vj00 | Basic call handling in 3GPP CS domain | Rel-19 |
| TS 23.057 vj00 | Mobile Execution Environment (MExE) Specification | Rel-19 |
| TS 23.060 vj00 | GPRS Service Description Stage 2 | Rel-19 |
| TS 23.078 vj00 | CAMEL Phase 4 Stage 2 Specification | Rel-19 |
| TS 23.107 vj00 | UMTS QoS Framework | Rel-19 |
| TS 23.110 vj00 | Access Stratum Services Specification | Rel-19 |
| TS 23.119 vj00 | Gateway Location Register (GLR) Stage 2 Description | Rel-19 |
| TS 23.125 v1700 | Flow Based Charging Architecture | Rel-7 |
| TS 23.141 vj00 | Presence Service Stage 2 Architecture | Rel-19 |
| TS 23.171 v1300 | LCS Stage 2 Specification for UMTS | Rel-4 |
| TS 23.207 vj00 | End-to-End QoS Framework for GPRS | Rel-19 |
| TS 23.218 vj00 | IMS Call Model Specification | Rel-19 |
| TS 23.221 vj00 | 3GPP System Architectural Requirements | Rel-19 |
| TS 23.271 vj00 | LCS Stage 2 Specification | Rel-19 |
| TS 23.278 vj00 | CAMEL for IMS Stage 2 Specification | Rel-19 |
| TR 23.976 vj00 | Push Service Requirements Analysis | Rel-19 |
| TR 23.979 vj00 | PoC over 3GPP Systems Architectural Requirements | Rel-19 |
| TR 23.981 vj00 | IPv4 IMS Interworking and Migration Study | Rel-19 |
| TS 24.228 v1500 | IP Multimedia Call Control Signaling Flows | Rel-5 |
| TS 24.229 vj50 | IMS call control protocol based on SIP and SDP | Rel-19 |
| TS 24.623 vj00 | XCAP Protocol for Supplementary Services | Rel-19 |
| TS 25.304 vj00 | UTRA Idle Mode Procedures Specification | Rel-19 |
| TS 25.305 vj00 | UTRAN UE Positioning Stage 2 | Rel-19 |
| TS 25.367 vj00 | Home NodeB Mobility Procedures | Rel-19 |
| TS 25.413 vj00 | Radio Access Network Application Part (RANAP) | Rel-19 |
| TS 26.150 vj00 | Syndicated Feed Reception (SFR) Specification | Rel-19 |
| TS 26.346 vj20 | MBMS User Services Media Codecs & Protocols | Rel-19 |
| TR 26.937 vj00 | 3GPP PSS Characterization | Rel-19 |
| TR 26.946 vj00 | MBMS User Services Overview | Rel-19 |
| TS 27.060 vj00 | TE-MT Interworking for Packet Domain | Rel-19 |
| TS 28.655 vj00 | GERAN NRM IRP Information Service | Rel-19 |
| TS 28.702 vj00 | Core Network NRM IRP Information Service | Rel-19 |
| TS 28.708 vj00 | EPC NRM Integration Reference Point Information Service | Rel-19 |
| TS 28.709 vj00 | EPC NRM IRP Solution Set Definitions | Rel-19 |
| TS 29.119 vj00 | GTP for GLR in 3GPP Networks | Rel-19 |
| TS 29.274 vj50 | GTPv2-C Control Plane Protocol Specification | Rel-19 |
| TS 31.111 vj30 | USIM Application Toolkit (USAT) Specification | Rel-19 |
| TS 31.112 v1800 | USAT Interpreter System Architecture | Rel-8 |
| TS 32.102 vj00 | Telecom Management Physical Architecture Framework | Rel-19 |
| TS 32.240 vj40 | Charging Management Architecture & Principles | Rel-19 |
| TS 32.251 vj00 | PS Domain Charging Management | Rel-19 |
| TS 32.270 vj00 | MMS Charging Management Specification | Rel-19 |
| TS 32.271 vj20 | 3GPP LCS Charging Management Spec | Rel-19 |
| TS 32.272 vj00 | Charging for Push-to-Talk over Cellular (PoC) | Rel-19 |
| TS 32.273 vj00 | MBMS Charging Management | Rel-19 |
| TS 32.278 vj00 | Monitoring Events Offline Charging Specification | Rel-19 |
| TS 32.295 vj00 | 3GPP Charging: CDR Transfer via GTP' Protocol | Rel-19 |
| TS 32.296 vj00 | Online Charging System (OCS) Architecture | Rel-19 |
| TS 32.297 vj00 | Charging Data Record File Transfer | Rel-19 |
| TS 32.298 vj30 | Charging Data Record (CDR) Parameter Specification | Rel-19 |
| TS 32.401 vj00 | Performance Management Concept & Requirements | Rel-19 |
| TS 32.622 vb10 | Generic Network Resources IRP NRM | Rel-11 |
| TS 32.632 vb00 | Core Network Resources IRP: Network Resource Model | Rel-11 |
| TS 32.652 vc00 | GERAN Network Resources NRM for Configuration Management | Rel-12 |
| TS 32.732 vb00 | IMS Network Resource Model IRP: Information Service | Rel-11 |
| TS 32.752 vb01 | EPC NRM IRP Information Service | Rel-11 |
| TS 32.756 vb00 | EPC NRM IRP Solution Set Definitions | Rel-11 |
| TS 32.808 v1800 | Common User Profile Storage Framework | Rel-8 |
| TS 33.107 vj00 | Lawful Interception Architecture & Functions | Rel-19 |
| TS 33.108 vj00 | LI Handover Interface Specification | Rel-19 |
| TS 43.051 vj00 | GERAN Stage 2 Service Description | Rel-19 |
| TS 43.129 vj00 | PS Handover in GERAN A/Gb and GAN Modes | Rel-19 |
| TS 43.130 vj00 | Iur-g Interface Overview | Rel-19 |
| TS 43.318 vj00 | Generic Access Network (GAN) Stage 2 | Rel-19 |
| TR 43.902 vj00 | GAN Enhancements Feasibility Study | Rel-19 |
| TS 44.060 vj00 | GERAN RLC/MAC Protocol Specification | Rel-19 |
| TS 44.160 vg00 | GERAN Iu Mode RLC/MAC Protocol Specification | Rel-16 |
| TS 44.318 vj00 | Generic Access Network (GAN) Interface Procedures | Rel-19 |
| TR 44.901 vj00 | Extended NACC for External Cell Change | Rel-19 |
| TR 45.903 vj00 | SAIC Feasibility Study for GSM Networks | Rel-19 |
| TS 51.021 vj00 | RF test methods and conformance requirements for GSM BSS | Rel-19 |
| TS 52.402 vj00 | GSM Performance Management Measurements | Rel-19 |