5.1 Control and user planes

23.4013GPPGeneral Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) accessRelease 18TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.1.0 General

NOTE:

– Refer to TS 23.402 [2] for the corresponding protocol stack for PMIP based S5/S8.

– Refer to TS 23.203 [6] for the corresponding protocol stack for Policy Control and Charging (PCC) function related reference points.

5.1.1 Control Plane

5.1.1.1 General

The control plane consists of protocols for control and support of the user plane functions:

– controlling the E-UTRA network access connections, such as attaching to and detaching from E-UTRAN;

– controlling the attributes of an established network access connection, such as activation of an IP address;

– controlling the routing path of an established network connection in order to support user mobility; and

– controlling the assignment of network resources to meet changing user demands.

The following control planes are used in E-UTRAN mode.

5.1.1.2 eNodeB – MME

Legend:

– S1 Application Protocol (S1-AP): Application Layer Protocol between the eNodeB and the MME.

– Stream Control Transmission Protocol (SCTP): This protocol guarantees delivery of signalling messages between MME and eNodeB (S1). SCTP is defined in RFC 4960 [35].

Figure 5.1.1.2-1: Control Plane for S1-MME Interface

NOTE: Refer to TS 36.300 [5] for the corresponding control plane for the HeNB Subsystem – MME.

5.1.1.3 UE – MME

Legend:

– NAS: The NAS protocol supports mobility management functionality and user plane bearer activation, modification and deactivation. It is also responsible of ciphering and integrity protection of NAS signalling.

– LTE-Uu: The radio protocol of E-UTRAN between the UE and the eNodeB is specified in TS 36.300 [5].

Figure 5.1.1.3-1: Control Plane UE – MME

5.1.1.4 SGSN – MME

Legend:

– GPRS Tunnelling Protocol for the control plane (GTP‑C): This protocol tunnels signalling messages between SGSN and MME (S3).

– User Datagram Protocol (UDP): This protocol transfers signalling messages. UDP is defined in RFC 768 [26].

Figure 5.1.1.4-1: Control Plane for S3 Interface

5.1.1.5 SGSN – S‑GW

Legend:

– GPRS Tunnelling Protocol for the control plane (GTP‑C): This protocol tunnels signalling messages between SGSN and S‑GW (S4).

– User Datagram Protocol (UDP): This protocol transfers signalling messages. UDP is defined in RFC 768 [26].

Figure 5.1.1.5-1: Control Plane for S4 interface

5.1.1.6 S‑GW – P‑GW

Legend:

– GPRS Tunnelling Protocol for the control plane (GTP‑C): This protocol tunnels signalling messages between S‑GW and P‑GW (S5 or S8).

– User Datagram Protocol (UDP): This protocol transfers signalling messages between S‑GW and P‑GW. UDP is defined in RFC 768 [26].

Figure 5.1.1.6-1: Control Plane for S5 and S8 interfaces

5.1.1.7 MME – MME

Legend:

– GPRS Tunnelling Protocol for the control plane (GTP‑C): This protocol tunnels signalling messages between MMEs (S10).

– User Datagram Protocol (UDP): This protocol transfers signalling messages between MMEs. UDP is defined in RFC 768 [26].

Figure 5.1.1.7-1: Control Plane for S10 interface

5.1.1.8 MME – S‑GW

Legend:

– GPRS Tunnelling Protocol for the control plane (GTP‑C): This protocol tunnels signalling messages between MME and S‑GW (S11).

– User Datagram Protocol (UDP): This protocol transfers signalling messages. UDP is defined in RFC 768 [26].

Figure 5.1.1.8-1: Control Plane for S11 interface

5.1.1.9 MME – HSS

Legend:

– Diameter: This protocol supports transferring of subscription and authentication data for authenticating/authorizing user access to the evolved system between MME and HSS (S6a). Diameter is defined in RFC 3588 [31].

– Stream Control Transmission Protocol (SCTP): This protocol transfers signalling messages. SCTP is defined in RFC 4960 [35].

Figure 5.1.1.9-1: Control Plane for S6a interface

5.1.1.10 MME – EIR

Legend:

– Diameter: This protocol supports UE identity check procedure between MME and EIR (S13). Diameter is defined in RFC 3588 [31].

– Stream Control Transmission Protocol (SCTP): This protocol transfers signalling messages. SCTP is defined in RFC 4960 [35].

Figure 5.1.1.10-1: Control Plane for S13 interface

5.1.1.11 Void

5.1.1.12 MME – CSS

Legend:

Diameter: This protocol supports transferring of CSG subscription data for roaming subscribers only between MME and CSS (S7a). Diameter is defined in RFC 3588 [31].

Stream Control Transmission Protocol (SCTP): This protocol transfers signalling messages. SCTP is defined in RFC 4960 [35].

Figure 5.1.1.12-1: Control Plane for S7a interface

5.1.1.13 MME – RCAF

Legend:

Nq-AP: This application layer protocol supports the IMSI and APN retrieval procedure between the RCAF and the MME.

Stream Control Transmission Protocol (SCTP): This protocol transfers signalling messages. SCTP is defined in RFC 4960 [35].

Figure 5.1.1.13-1: Control Plane for Nq interface

5.1.2 User Plane

5.1.2.1 UE – P‑GW user plane with E-UTRAN

Legend:

– GPRS Tunnelling Protocol for the user plane (GTP‑U): This protocol tunnels user data between eNodeB and the S‑GW as well as between the S‑GW and the P‑GW in the backbone network. GTP shall encapsulate all end user packets. End user Ethernet packets are only used with a combined PDN GW+SMF (as specified in TS 23.501 [83]).

– MME controls the user plane tunnel establishment and establishes User Plane Bearers between eNodeB and S‑GW.

– UDP/IP: These are the backbone network protocols used for routing user data and control signalling.

– LTE-Uu: The radio protocols of E-UTRAN between the UE and the eNodeB are specified in TS 36.300 [5].

Figure 5.1.2.1-1: User Plane

5.1.2.2 eNodeB – S‑GW

Legend:

– GPRS Tunnelling Protocol for the user plane (GTP‑U): This protocol tunnels user data between eNodeB and S‑GW.

– User Datagram Protocol (UDP): This protocol transfers user data. UDP is defined in RFC 768 [26].

Figure 5.1.2.2-1: User Plane for eNodeB – S‑GW

NOTE: Refer to TS 36.300 [5] for the corresponding user plane for the HeNB Subsystem – S-GW.

5.1.2.3 UE – PDN GW user plane with 2G access via the S4 interface

Legend:

– GPRS Tunnelling Protocol for the user plane (GTP‑U): This protocol tunnels user data between SGSN and the S‑GW as well as between the S‑GW and the P‑GW in the backbone network. GTP shall encapsulate all end user IP packets.

– UDP/IP: These are the backbone network protocols used for routing user data and control signalling.

– Protocols on the Um and the Gb interfaces are described in TS 23.060 [7].

Figure 5.1.2.3-1: User Plane for A/Gb mode

5.1.2.4 UE – PDN GW user plane with 3G access via the S12 interface

Legend:

– GPRS Tunnelling Protocol for the user plane (GTP‑U): This protocol tunnels user data between UTRAN and the S‑GW as well as between the S‑GW and the P‑GW in the backbone network. GTP shall encapsulate all end user IP packets.

– UDP/IP: These are the backbone network protocols used for routing user data and control signalling.

– Protocols on the Uu interface are described in TS 23.060 [7].

– SGSN controls the user plane tunnel establishment and establish a Direct Tunnel between UTRAN and S‑GW as shown in Figure 5.1.2.4-1.

Figure 5.1.2.4-1: User Plane for UTRAN mode and Direct Tunnel on S12

5.1.2.5 UE – PDN GW user plane with 3G access via the S4 interface

NOTE: Please refer to TS 23.402 [2] for the corresponding stack for PMIP based S5/S8.

Legend:

– GPRS Tunnelling Protocol for the user plane (GTP‑U): This protocol tunnels user data between UTRAN and the SGSN, between SGSN and S‑GW as well as between the S‑GW and the P‑GW in the backbone network. GTP shall encapsulate all end user IP packets.

– UDP/IP: These are the backbone network protocols used for routing user data and control signalling.

– Protocols on the Uu and the Iu interfaces are described in TS 23.060 [7].

– SGSN controls the user plane tunnel establishment and establishes a tunnel between SGSN and S‑GW. If Direct Tunnel is established between UTRAN and S‑GW, see Figure 5.1.2.4-1.

Figure 5.1.2.5-1: User Plane for Iu mode

5.1.2.6 UE – P‑GW user plane with Control Plane CIoT EPS Optimisations

Legend:

– GTP-u (GPRS Tunnelling Protocol User plane): This protocol tunnels user data between MME and the S‑GW as well as between the S‑GW and the P‑GW in the backbone network. GTP shall encapsulate all end user packets. End user Ethernet packets are only used with a combined PDN GW+SMF (as specified in TS 23.501 [83]).

– UDP/IP: These are the backbone network protocols used for routing user data and control signalling.

– NAS: this is the Non-Access Stratum Layer used to carry Data between UE and MME and may include Header compression and security functions of user plane IP data. Whether a convergence protocol sublayer may be required for this purpose is a stage 3 matter.

Figure 5.1.2.6-1: User Plane with Control Plane CIoT EPS Optimisations