3GPP Analyzer

S1AP

S1 Application Protocol

InterfaceIntroduced Rel-8

Definition

The signaling protocol over the S1-MME interface between eNodeB and MME, carrying context setup, handover, and paging procedures.

Evolution Across Releases

  • Defined in Rel-8; its 5G counterpart is NGAP over the N2 interface.

Related Specifications