3 Definitions and abbreviations

29.2813GPPGeneral Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)Release 17TS

3.1 Definitions

For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].

Common Tunnel Endpoint Identifier (C-TEID): Unambiguously identifies a tunnel endpoint in the receiving GTP-U protocol entity for a given UDP/IP endpoint. The sending end side of a GTP tunnel locally assigns the C-TEID value used in the TEID field and signals it to the destination Tunnel Endpoint using a control plane message.

GTP-U Message: GTP-U (user plane) messages are either user plane messages or signalling messages. User plane messages are used to carry user data packets between GTP-U entities. Signalling messages are sent between network nodes for path management and tunnel management.GTP-U peer: node implementing at least one side of any of the GTP user plane based protocols. RNC, SGSN, GGSN, eNodeB, SGW, ePDG, gNB, N3IWF, UPF, PGW or TWAN or MME.

GTP-U Tunnel: A GTP-U tunnel is identified in each node with a TEID, an IP address and a UDP port number. A GTP-U tunnel is necessary to enable forwarding packets between GTP-U entities.

GTP-U Tunnel Endpoint: A GTP-U tunnel endpoint identifies a user plane context (e.g EPS bearer, PDU session or a RAB) for which a received GTP-U packet is intended. A given GTP-U tunnel endpoint may receive GTP-U packets from more than one source GTP-U peer (See clause 4.3.0).UDP/IP Path: Connection-less unidirectional or bidirectional path defined by two end-points. An IP address and a UDP port number define an end-point. A UDP/IP path carries GTP messages between network nodes related to one or more GTP tunnels.

GTP-PDU: GTP Protocol Data Unit (PDU) is a GTP-U message, which may be either a G-PDU or a signalling message.

G-PDU: User data packet (T-PDU) plus GTP-U header, sent between GTP network nodes.

Signalling Message: A GTP-U message (GTP-PDU that is not a G-PDU) sent between GTP network nodes. These may be Path Management messages or Tunnel Management messages.

T-PDU: A user data packet, for example an IP datagram, sent between a UE and a network entity in an external packet data network. A T-PDU is the payload that is tunnelled in the GTP-U tunnel.

Tunnel Endpoint Identifier (TEID): Unambiguously identifies a tunnel endpoint in the receiving GTP-U protocol entity for a given UDP/IP endpoint. The receiving end side of a GTP tunnel locally assigns the TEID value the transmitting side has to use. The TEID values are exchanged between tunnel endpoints using control plane message.

Trusted WLAN Access Network: see 3GPP TS 23.402 [23].

3.2 Abbreviations

For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1].

C-TEID Common Tunnel Endpoint IDentifier

EN-DC E-UTRA-NR Dual Connectivity

ePDG Evolved Packet Data Gateway

GSN GPRS Support Node

GGSN Gateway GPRS Support Node

G-PDU GTP encapsulated user Plane Data Unit

GTP GPRS Tunnelling Protocol

GTP-C GTP Control

GTP-U GTP User

IE Information Element

IGMP Internet Group Management Protocol

IP Internet Protocol

IPv4 Internet Protocol version 4

IPv6 Internet Protocol version 6

MME Mobility Management Entity

PDU Packet Data Unit

PGW PDN Gateway

QoS Quality of Service

RANAP Radio Access Network Application Part

RNC Radio Network Controller

SGSN Serving GPRS Support Node

SGW Serving Gateway

TEID Tunnel Endpoint IDentifier

T-PDU Transport PDU

TWAN Trusted WLAN Access Network

UDP User Datagram Protocol

UTRAN UMTS Terrestrial Radio Access Network