Description
The Access Point Name (APN) is a critical configuration parameter in 3GPP packet-switched networks, acting as a reference point to a Packet Data Network (PDN). Structurally, an APN is a Fully Qualified Domain Name (FQDN) composed of two parts: the APN Network Identifier (mandatory), which specifies the external PDN, and the APN Operator Identifier (optional), which identifies the operator's network. When a User Equipment (UE) initiates a Packet Data Protocol (PDP) Context activation in 3G/UMTS or a PDN Connection in 4G/5G, it includes the APN. The network uses this APN to select the appropriate Gateway GPRS Support Node (GGSN) in UMTS or the Packet Data Network Gateway (PGW) in EPS/5GC, which serves as the anchor point to the external network.
Upon receiving an activation request with an APN, the Serving GPRS Support Node (SGSN) in UMTS or the Mobility Management Entity (MME)/Session Management Function (SMF) in EPS/5GC performs a DNS query. This query resolves the APN FQDN to the IP address(es) of the suitable gateway (GGSN/PGW). The selection process considers subscriber profiles, network policies, and load balancing. The chosen gateway then establishes the data session, allocates an IP address to the UE (often via DHCP), and sets up the user plane bearers for data traffic. The APN thus directly dictates the routing path, the external network reachable, and the Quality of Service (QoS) profile applied to the connection.
The APN's role extends beyond simple connectivity. It is intrinsically linked to policy and charging control. The APN value is used by the Policy and Charging Rules Function (PCRF) or Policy Control Function (PCF) to determine which policy and charging rules apply to the subscriber's data session. This enables operators to offer differentiated services—such as dedicated APNs for Internet, MMS, IMS, or enterprise VPNs—each with distinct bandwidth limits, security settings, and billing models. In 5G, the concept evolves with the Data Network Name (DNN), which is functionally equivalent to the APN, providing connectivity to a specific data network while integrating with network slicing and enhanced policy frameworks.
Purpose & Motivation
The APN was introduced to solve the fundamental problem of connecting mobile subscribers to multiple, distinct packet data networks beyond the mobile operator's core. In early GPRS, without such an identifier, all data traffic would be homogeneously routed to a single external network (like the public internet), preventing service differentiation, secure corporate access, and specialized services like WAP or MMS. The APN provides the necessary logical separation, allowing the network to select different gateways and apply specific policies based on the intended service.
Historically, before standardized APNs, value-added data services were difficult to implement and manage. The APN mechanism created a scalable, subscriber-configurable way to direct sessions. It addressed limitations in routing, billing, and service quality by enabling the network to identify the destination PDN during session establishment. This was crucial for the commercial success of mobile data, as it allowed operators to offer tiered service plans, partner with content providers, and support secure enterprise connectivity through dedicated APNs with private addressing.
Furthermore, the APN is central to policy enforcement and charging. By associating a session with a specific APN, operators can deploy distinct policy rules for traffic shaping, access control, and quality of service. It enables accurate billing—for example, charging data used on a 'internet' APN differently from data on a 'mms' APN. This flexibility motivated its creation and sustained evolution, forming the basis for the more advanced DNN parameter in 5G systems, which continues this role within network slicing and service-based architectures.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (40 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, enhancements were introduced for the APN function, including the handling of the extended EPS quality of service IE and extended APN-AMBR IE, with corrections to APN-AMBR and its coding. The release also specified the establishment of a PDN connection of non-IP type using the default APN based on an indication from an ESMS entity and provided an enhancement of APN rate control for mobile-originated exception data.
- Handling of extended EPS quality of service IE and extended APN-AMBR IE TS 24.301CR2919
- Correction of APN-AMBR TS 24.301CR3031
- MSB & LSB in the coding of Extended QoS and Extended APN AMBR IE TS 24.301CR3037
- Code points split into "unused values" and "reserved values" TS 24.301CR3058
- Establishment of a PDN connection of non-IP type using the default APN based on indication from ESMS entity TS 24.301CR3156
- AMF Region ID (8 bits), AMF Set ID (10 bits), and AMF Pointer (6 bits) TS 24.501CR0030
+ 3 more changes
In Release 16, the APN function was enhanced to support the signalling of EPS APN rate control parameters during 5G PDU session establishment. This release also defined procedures for applying this APN rate control during inter-system change between EPS and 5GS. Furthermore, corrections were made to the handling of APN-based congestion control to ensure proper network behavior.
- Add PointCoordinate, Speed, Heading nodes in 5.2.48W TS 24.483CR0072
- Signalling of EPS APN rate control parameters during PDU session establishment TS 24.501CR2164
- IEIs assignment for Bearer level QoS IE and APN-AMBR IE TS 24.244CR0057
- Applying APN rate control at inter-system change TS 24.301CR3287
- Correction to handling of APN based congestion control TS 24.301CR3376
- Correction on the description of code point for 128-5G-EA3 TS 24.501CR1221
+ 1 more changes
In Release 17, updates to the Access Point Name (APN) function included the introduction of a new management object for APN configuration and a correction to the minimum range value for the APN-AMBR (Aggregate Maximum Bit Rate) for both downlink and uplink. Additionally, corrections were made to the reference point descriptions for the 5G System (5GS) and for MCPTT-5.
- Management object for APN configuration TS 24.483CR0096
- Correction on Reference Points for 5GS TS 32.240CR0426
- Correction to MCPTT-5 reference point description TS 23.379CR0293
- Fix typo in the minimum range of APN-AMBR for downlink or uplink (extended-2) TS 24.301CR3525
- Introduction of Reference point representation for Converged Charging TS 32.240CR0444
- Adding ProSe Converge Charging Architecture in reference point representation TS 32.277CR0050
In Release 18, the APN function saw updates primarily through the clarification and introduction of new charging-related reference points. Specifically, the release introduced the **N108** reference point and updated the definition of the **N42** reference point within the charging architecture. These changes provided greater specificity for charging interactions, though the core APN procedures for user plane connectivity remained unchanged.
- Reference point between HSS and DCSF TS 23.228CR1305
- Functional model reference points TS 23.280CR0307
- Clarification regarding the protocol used on new reference points TS 23.280CR0313
- Add reference point between MMS node and CHF TS 32.240CR0469
- Clarification on Interfaces and Reference Points Used for DC TS 23.228CR1325
- Corrections to reference point CSC-16 TS 23.280CR0348
+ 8 more changes
In Release 19, the primary update for the Access Point Name (APN) function introduced new procedures for the handling of APN congestion control. This enhancement specifically defines network behavior upon the reception of an ESM data transport message, providing a mechanism to manage congestion at the APN level.
In Release 20, the update to the APN function specifically provided a clarification regarding point-to-point communication. This clarification was applied to the technical procedures defined in clause 10.16.4.2 of the specification. The change served to refine the definition and application of point-to-point services, which involve communication between only two network terminations.
- Clarification on the point-to-point communication in clause 10.16.4.2 TS 23.280CR0696
Explore further
Broader topics and technologies where APN plays a role.
Defining Specifications
3GPP specifications that define or reference APN, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TS 22.234 vd10 | 3GPP-WLAN Interworking Index Specification | Rel-13 |
| TR 22.802 ve00 | Study on Need for Multiple APNs in MTC | Rel-14 |
| TR 22.934 vd00 | 3GPP-WLAN Interworking Feasibility Study | Rel-13 |
| TS 23.060 vj00 | GPRS Service Description Stage 2 | Rel-19 |
| TS 23.179 vd50 | MCPTT Functional Architecture | Rel-13 |
| TS 23.180 vj10 | MC services support in IOPS mode | Rel-19 |
| TS 23.207 vj00 | End-to-End QoS Framework for GPRS | Rel-19 |
| TS 23.228 vj50 | IMS Stage-2 Service Description | Rel-19 |
| TS 23.234 vd10 | 3GPP-WLAN Interworking Index | Rel-13 |
| TS 23.271 vj00 | LCS Stage 2 Specification | Rel-19 |
| TS 23.273 vj50 | 5G Location Services Stage 2 Architecture | Rel-19 |
| TS 23.280 vk10 | Common Architecture for Mission Critical Services | Rel-20 |
| TS 23.327 vd10 | 3GPP-WLAN Mobility Stage 2 Description | Rel-13 |
| TS 23.379 vk00 | MCPTT Functional Architecture | Rel-20 |
| TS 23.558 vk00 | Architecture for Edge Applications | Rel-20 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TS 23.701 vc00 | WebRTC Access to IMS Architecture Study | Rel-12 |
| TR 23.758 vh00 | Study on Edge Application Architecture | Rel-17 |
| TS 23.802 v1700 | Enhanced End-to-End QoS Architecture | Rel-7 |
| TR 23.923 v1300 | Mobile IP+ Feasibility Study for UMTS/GPRS | Rel-4 |
| TR 23.976 vj00 | Push Service Requirements Analysis | Rel-19 |
| TS 24.161 vj00 | Network-Based IP Flow Mobility (NBIFOM) | Rel-19 |
| TS 24.229 vj50 | IMS call control protocol based on SIP and SDP | Rel-19 |
| TS 24.234 vc20 | 3GPP-WLAN Interworking Network Selection | Rel-12 |
| TS 24.244 vj00 | Wireless LAN Control Plane Protocol | Rel-19 |
| TS 24.301 vj60 | NAS protocol for Evolved Packet System | Rel-19 |
| TS 24.302 vj00 | Access to EPC via non-3GPP networks; Stage 3 | Rel-19 |
| TS 24.483 vj20 | Mission Critical Services Management Object | Rel-19 |
| TS 24.484 vj30 | MCS Configuration Management | Rel-19 |
| TS 24.501 vj50 | 5G NAS Protocols Specification | Rel-19 |
| TS 25.401 vj00 | UTRAN Overall Architecture | Rel-19 |
| TS 25.413 vj00 | Radio Access Network Application Part (RANAP) | Rel-19 |
| TS 25.423 vj00 | UTRAN RNSAP Specification | Rel-19 |
| TR 25.931 vj00 | UTRAN Signalling Procedures Examples | Rel-19 |
| TS 26.346 vj20 | MBMS User Services Media Codecs & Protocols | 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 29.061 vj00 | Packet Domain Interworking for PLMN | Rel-19 |
| TS 29.161 vc00 | 3GPP-WLAN Interworking Requirements | Rel-12 |
| TS 29.274 vj50 | GTPv2-C Control Plane Protocol Specification | Rel-19 |
| TS 29.890 vg00 | CT3 5G System Technical Report | Rel-16 |
| TS 31.102 vj40 | USIM Application Specification | Rel-19 |
| TS 31.121 vi50 | UICC-terminal interface test specification | Rel-18 |
| TS 31.829 vd00 | ISIM Conformance Requirements Technical Report | Rel-13 |
| TS 32.240 vj40 | Charging Management Architecture & Principles | Rel-19 |
| TS 32.251 vj00 | PS Domain Charging Management | Rel-19 |
| TS 32.272 vj00 | Charging for Push-to-Talk over Cellular (PoC) | Rel-19 |
| TS 32.277 vj20 | Charging Management for Proximity Services (ProSe) | Rel-19 |
| TS 32.278 vj00 | Monitoring Events Offline Charging Specification | Rel-19 |
| TS 32.296 vj00 | Online Charging System (OCS) Architecture | Rel-19 |
| TS 32.401 vj00 | Performance Management Concept & Requirements | Rel-19 |
| TS 32.808 v1800 | Common User Profile Storage Framework | Rel-8 |
| TS 33.141 vj00 | Security for Presence Service (Ut reference point) | Rel-19 |
| TS 33.203 vj10 | IMS Security Specification | Rel-19 |
| TS 33.822 v1800 | Security Architecture for Inter-Access Mobility | Rel-8 |
| TR 33.978 v1800 | Interim Security for Early IMS | Rel-8 |
| TS 52.402 vj00 | GSM Performance Management Measurements | Rel-19 |