NSSF (Network Slice Selection Function)

Also known as: Network Slice Selection Function

The NSSF is the 5G core function that selects the set of network slice instances serving a UE and the appropriate AMF for a given registration request. It maps Requested/Allowed NSSAI to concrete slice instances based on subscription, roaming agreements and operator policy. Because slice selection determines which set of NFs a subscriber actually reaches, NSSF integrity is critical to slice isolation.

Categories: Core Network

NSSF in context

The mobile core carries subscriber sessions, mobility and policy. 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.

To place NSSF in the wider telecom-security picture, review 5G, 5G SA, 5G NSA, 5G SBA, ACL and AES — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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