For the purposes of the present document, the terms and definitions given in
TR 21.905 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.
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:
For the purposes of the present document, the abbreviations given in
TR 21.905 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.
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