Specification

X2 layer 1

in Specification, LTE, X2

The main functions of X2 interface layer 1 are as following:

X2 Application Protocol (X2AP)

in eNodeB, Specification, E-UTRAN, LTE, X2, X2AP

The X2AP protocol is used to handle the UE mobility within E-UTRAN and provides the following functions:

X2 Signalling Transport

in Specification, LTE, X2

X2 signalling bearer provides the following functions:

GPRS Tunnelling Protocol User Plane (GTP-U)

in GTP-U, S4, S5, S8, Specification, LTE, S1, X2

GTP-U protocol is used over S1-U, X2, S4, S5 and S8 interfaces of the Evolved Packet System (EPS).

GTP-U Transport

in S4, S5, S8, Specification, UDP, IP, LTE, S1, X2

The transport layer for data streams over S1, X2, S4, S5 and S8  is an IP based Transport.

S1 Application Protocol (S1AP)

in Specification, LTE, S1AP

S1AP provides the signalling service between E-UTRAN and the evolved packet core (EPC) and has following functions:

S1 Signalling Transport

in IPv4, IPv6, Specification, IP, LTE, S1

S1 signalling bearer provides the following functions:

S1 layer 1

in Specification, LTE, S1

The main functions of S1 interface layer 1 are as following:

Non-Access-Stratum (NAS) Protocol

in NAS, Specification, LTE

The non-access stratum (NAS) is highest stratum of the control plane between UE and MME at the radio interface.

Air Interface Physical Layer

in Physical Layer, Specification, Uu, LTE

The LTE air interface physical layer offers data transport services to higher layers. The access to these services is through the use of a transport channel via the MAC sub-layer.