Description
The UE Route Selection Policy (URSP) is a cornerstone of the 5G system's ability to support diverse services with vastly different requirements through network slicing and concurrent access to multiple data networks. It is a structured policy, defined in 3GPP TS 23.503, that the Policy Control Function (PCF) provisions to the User Equipment (UE) via the Access and Mobility Management Function (AMF). The URSP consists of a prioritized list of URSP rules. Each rule contains two main components: a Traffic Descriptor and a list of Route Selection Descriptors (RSDs). The Traffic Descriptor defines the set of application traffic to which the rule applies. It can use criteria such as Destination Internet Protocol (IP) addresses/prefixes, port numbers, protocol IDs, Domain Name System (DNS) queries, or, most importantly, an OS/Application ID that directly identifies a specific application on the UE. The Route Selection Descriptor(s) then define the network resources that should be used for matching traffic. A single RSD can specify a combination of a Data Network Name (DNN), a Single-Network Slice Selection Assistance Information (S-NSSAI), and a Session and Service Continuity (SSC) mode. The UE's operating system or policy enforcement function evaluates these rules in priority order for each new application flow or socket connection. When a match is found, the UE uses the information in the RSD to establish a Protocol Data Unit (PDU) Session with the appropriate DNN and network slice, or to route the traffic over an existing matching PDU Session. This allows a single UE to have multiple active PDU Sessions—for example, one for enhanced Mobile Broadband (eMBB) to a public internet DNN, and another for Ultra-Reliable Low-Latency Communication (URLLC) to a private industrial network slice—with applications automatically mapped to the correct session. The URSP mechanism shifts significant intelligence to the UE, enabling dynamic, application-aware network resource selection without requiring constant network intervention for every flow.
Purpose & Motivation
URSP was created to address the fundamental challenge of efficiently supporting the 5G vision of a single network infrastructure catering to massively diverse use cases, from broadband to IoT to critical communications. Pre-5G networks primarily associated a UE with a single default data connection (PDN connection in 4G). While some form of dedicated bearers could provide different quality of service (QoS), the selection was network-controlled and limited in scope, lacking deep application awareness. URSP solves this by providing a flexible, programmable policy framework that allows the network operator to instruct the UE on how to map its myriad applications to the appropriate network slices and data networks. This enables simultaneous connectivity to multiple logical networks, optimal resource utilization, and seamless user experience where, for instance, a vehicle's telematics uses a low-latency slice while its infotainment uses a high-bandwidth slice. It was motivated by the need for automation and scalability; manually configuring each application on the UE or having the network micro-manage every flow is impractical. URSP empowers the UE to make intelligent local routing decisions based on operator-defined policies, which is essential for realizing the full economic and technical potential of network slicing and 5G service-based architecture.
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (314 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the URSP function was newly introduced to allow the network to provide the UE with policies for selecting and associating PDU Sessions based on application traffic. Key introductions included the definition of URSP rules with traffic descriptors like DNN, the specification of a default URSP rule, and the procedural mechanism for the network to create or update these rules to guide PDU Session establishment, including for scenarios like redundant paths or Non-3GPP access. The release also clarified UE local configuration as an option and detailed components, validation, and update triggers for the policy.
- Handling of error case when UE gets URSP from VPLMN TS 24.501CR0256
- Adding connection capabilities in URSP rules TS 24.526CR0003
- Clarification on priority of URSP and configuration of association between application and LADN DNN TS 23.501CR0609
- Adding UE Local Configuration as an additional option to the URSP TS 23.501CR0786
- Description of components in URSP TS 23.503CR0008
- Default URSP Rule TS 23.503CR0017
+ 18 more changes
In Release 16, the URSP function was enhanced to support Multi-Access PDU Sessions (MA-PDU) with ATSSS rules, enabling the establishment of redundant transmission paths. It introduced new capabilities for background data transfer (xBDT) policy information and expanded URSP usage to scenarios including wireline 5G access and when the UE attaches to EPS. Furthermore, the release provided clarifications on validation criteria, pre-configured rules, and the storage of URSP rules in the USIM.
- Support of ATSSS rules and URSP rules for MA-PDU Sessions TS 23.503CR0187
- Support for Multi-Access PDU Session in URSP and PDU session selection TS 23.503CR0208
- Introduction of background data transfer policy information in URSP TS 24.526CR0043
- 5G-RG and W-AGF acting on behalf of FN-RG usage of URSP TS 24.526CR0065
- URSP rule provisioning for supporting xBDT TS 29.525CR0044
- URSP provisioning for xBDT TS 29.525CR0054
+ 26 more changes
In Release 17, URSP was enhanced to support the establishment of redundant PDU Sessions based on specific URSP rules, enabling more reliable connectivity. It also introduced mechanisms for an Application Function (AF) to provide guidance to the Policy Control Function (PCF) for the determination of proper URSP rules, influencing UE policy updates. Furthermore, new support was added for 5G ProSe UE-to-Network Relay operations and for the use of PDU Session Pair ID within URSP rules.
- Clarification on UE provides PDU Session Pair ID based on URSP rules TS 23.501CR2736
- Support of AF guidance to PCF determination of proper URSP rules TS 23.503CR0504
- Support of AF guidance to PCF determination of proper URSP rules TS 23.503CR0547
- URSP enhancement for the 5G ProSe UE-to-Network Relay support TS 23.503CR0569
- UE providing PDU Session Pair ID based on URSP rules TS 23.503CR0595
- UE required to not accept URSP signalled by non-subscribed SNPNs TS 24.501CR4135
+ 45 more changes
In Release 18, the URSP function was extended to support provisioning within the EPS (Evolved Packet System) for 4G networks, allowing URSP rules to be delivered to UEs connected to 4G. It also introduced enhancements for roaming scenarios, including the provisioning of URSP to route traffic to a VPLMN and support for URSP re-evaluation upon a PLMN change. Furthermore, support was added for standardized and operator-specific traffic categories within the URSP rules.
- Support URSP provisioning in EPS TS 23.501CR3924
- Support URSP provisioning in EPS TS 23.501CR4253
- Support URSP provisioning in EPS TS 23.503CR0839
- Update on NWDAF-assisted URSP TS 23.503CR0875
- Remove EN about NWDAF assisted URSP in TS23.503 TS 23.503CR0880
- Support standardized and operator-specific traffic categories in URSP TS 23.503CR0893
+ 170 more changes
In Release 19, key enhancements to URSP included its provisioning in EPS networks and new support for Background Data Transfer rules. The release also introduced clarifications for local offloading management and the precedence between VPLMN and HPLMN rules, while ensuring URSP and ANDSP parameters are correctly stored in non-volatile memory. Furthermore, procedures were corrected and refined for rule enforcement, removal, and operation in SNPN access modes.
- Support of URSP Provisioning in EPS TS 29.512CR1289
- Precedence of VPLMN specific URSP rules TS 29.525CR0376
- Support URSP provisioning in EPS indicator TS 29.525CR0382
- URSP rules provisioning for Background Data Transfer TS 29.525CR0385
- Complete the partially unsuccessful ursp rule delivery outcome TS 29.525CR0403
- Clarification on Local Offloading Management with URSP TS 23.501CR6249
+ 25 more changes
Explore further
Broader topics and technologies where URSP plays a role.
Defining Specifications
3GPP specifications that define or reference URSP, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 23.433 vk00 | SEAL Data Delivery (SEALDD) for Verticals | Rel-20 |
| TS 23.501 vk00 | 5G System Architecture Stage 2 | Rel-20 |
| TS 23.503 vk00 | 5G Policy and Charging Control Framework | Rel-20 |
| TS 23.558 vk00 | Architecture for Edge Applications | Rel-20 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TR 23.758 vh00 | Study on Edge Application Architecture | Rel-17 |
| TS 23.791 vg20 | NWDAF Data Collection & Analytics Framework | Rel-16 |
| TS 24.193 vj50 | ATSSS Procedures Specification | Rel-19 |
| TS 24.301 vj60 | NAS protocol for Evolved Packet System | Rel-19 |
| TS 24.501 vj50 | 5G NAS Protocols Specification | Rel-19 |
| TS 24.514 vj30 | Ranging & Sidelink Positioning in 5GS | Rel-19 |
| TS 24.526 vj30 | UE Policies for 5GS; Stage 3 | Rel-19 |
| TS 24.549 vj10 | SEAL Network Slice Capability Enablement Protocol | Rel-19 |
| TS 24.554 vj40 | 5G Proximity Services (ProSe) Protocols | Rel-19 |
| TS 26.501 vj30 | 5G Media Streaming (5GMS) Architecture | Rel-19 |
| TR 26.803 vh00 | 5G Media Streaming Extensions for Edge Processing | Rel-17 |
| TR 26.941 vj01 | 5G Media Slicing Extensions | Rel-19 |
| TS 29.507 vj40 | 5G Access & Mobility Policy Control Service | Rel-19 |
| TS 29.512 vj40 | 5G Session Management Policy Control Service | Rel-19 |
| TS 29.513 vj40 | 5G PCC Signalling Flows & QoS Mapping | Rel-19 |
| TS 29.514 vj40 | 5G System; Policy Authorization Service; Stage 3 | Rel-19 |
| TS 29.519 vj40 | UDR Usage for Policy & Exposure Data | Rel-19 |
| TS 29.520 vj40 | 5G Network Data Analytics Services Stage 3 | Rel-19 |
| TS 29.522 vj40 | 5G NEF Northbound APIs Stage 3 | Rel-19 |
| TS 29.523 vj20 | 5G Policy Control Event Exposure Service | Rel-19 |
| TS 29.525 vj40 | 5G UE Policy Control Service Stage 3 | Rel-19 |
| TS 29.890 vg00 | CT3 5G System Technical Report | Rel-16 |
| TS 31.102 vj40 | USIM Application Specification | Rel-19 |
| TR 33.882 vi01 | Technical Report on 5G Security for Personal IoT Networks | Rel-18 |
