Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 Application Protocol (S1AP)

Grounded in the official 3GPP Scope excerpt

TS 36.413 specifies the radio network layer signalling protocol operating over the S1 interface in E-UTRAN. It defines the S1 Application Protocol (S1AP), including the signalling procedures that support S1 interface functions. The protocol is developed in accordance with the general principles established in TS 36.401 and TS 36.410. A RAN or core engineer would open this specification when implementing, troubleshooting, or validating S1AP signalling between an eNB and the EPC — for example, when decoding S1AP messages in a protocol trace, resolving procedure failures on the S1 interface, verifying conformance of an S1AP implementation, or understanding the signalling behaviour expected of either endpoint during integration or interoperability testing.

Generated 7/26/2026 · cached for 90 days