URSP (UE Route Selection Policy)

Also known as: UE Route Selection Policy

URSP is the 3GPP policy set (TS 23.503) delivered by the PCF to a 5G UE that tells the UE which PDU session, slice (S-NSSAI), DNN and access to use for a given application or traffic descriptor. Correct URSP handling is fundamental to slice isolation: a UE that ignores or misapplies URSP can leak traffic across slices or use an unintended DNN.

Categories: Core NetworkProtocols and StandardsInternet and Routing

URSP in context

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how the specs interlock (for example 3GPP TS 33.501 with GSMA FS.34 for 5G SBA security), is essential for both design and audit work.

To place URSP in the wider telecom-security picture, review AF, Network Slice, Subnet, SCP, NDR and Suricata.

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