4 General aspects

37.4803GPPE1 general aspects and principlesRelease 17TS

This clause captures the E1 interface principles and characteristics.

Note: The principles, functions and procedures specified in this specification also apply to the case where E1AP is used between an ng-eNB-CU-CP and an ng-eNB-CU-UP or between an eNB-CP and an eNB-UP, unless stated otherwise.

4.1 E1 interface general principles

The general principles for the specification of the E1 interface are as follows:

– the E1 interface is open;

– the E1 interface supports the exchange of signalling information between the endpoints;

– from a logical standpoint, the E1 is a point-to-point interface between a gNB-CU-CP and a gNB-CU-UP, or between an ng-eNB-CU-CP and an ng-eNB-CU-UP, or between an eNB-CP and an eNB-UP.

NOTE 1: A point-to-point logical interface should be feasible even in the absence of a physical direct connection between the endpoints.

– the E1 interface separates Radio Network Layer and Transport Network Layer;

– the E1 interface enables exchange of UE associated information and non-UE associated information;

– the E1 interface is future proof to fulfil different new requirements, support of new services and new functions.

4.2 E1 interface specification objectives

The E1 interface specifications facilitate the following:

– inter-connection of a gNB-CU-CP and a gNB-CU-UP supplied by different manufacturers.

– inter-connection of an ng-eNB-CU-CP and an ng-eNB-CU-UP supplied by different manufacturers.

– inter-connection of an eNB-CP and an eNB-UP supplied by different manufacturers.