5 Elementary procedures between TSN AF and DS-TT

24.5393GPP5G System (5GS)Network to TSN translator (TT) protocol aspectsRelease 18Stage 3TS

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

5.1 General

The UE and the network may support transfer of standardized and deployment-specific port management information between a time-sensitive networking (TSN) AF and the DS-TT at the UE, to manage the port used at the DS-TT for a PDU session of "Ethernet" PDU session type, "IPv4" PDU session type, "IPv6" PDU session type or "IPv4v6" PDU session type. The port management messages are included in a Port management information container IE and transported using the UE-requested PDU session establishment procedure, the network-requested PDU session modification procedure or the UE-requested PDU session modification procedure as specified in 3GPP TS 24.501 [5] clauses 6.4.1.2, 6.3.2 and 6.4.2.

5.2 Procedures

5.2.1 Network-requested port management procedure

5.2.1.1 General

The purpose of the network-requested port management procedure is to enable the TSN AF to:

a) obtain the list of port management parameters supported by the DS-TT;

b) obtain the current values of port management parameters at the DS-TT port;

c) set the values of port management parameters at the DS-TT port;

d) subscribe to be notified by the DS-TT if the values of certain port management parameters change at the DS-TT port;

e) unsubscribe to be notified by the DS-TT for one or more port management parameters; or

f) delete a port management parameter-entry at the DS-TT port.

5.2.1.2 Network-requested port management procedure initiation

In order to initiate the network-requested port management procedure, the TSN AF shall:

a) encode the information about the port management parameters values to be read, the port management parameters values to be set, the port management parameters changes to (un)subscribe to, the port management parameter-entry to be deleted and whether the TSN AF requests the list of port management parameters supported by the DS-TT in a port management list IE as specified in clause 9.2 and include it in a MANAGE PORT COMMAND message;

c) send the MANAGE PORT COMMAND message to the UE via the PCF and the SMF as specified in 3GPP TS 23.502 [3]; and

d) start timer T100 (see example in figure 5.2.1.2.1).

Figure 5.2.1.2.1: Network-requested port management procedure

5.2.1.3 Network-requested port management procedure completion

Upon receipt of the MANAGE PORT COMMAND message, for each operation included in the port management list IE, the DS-TT shall:

a) if the operation code is "get capabilities", include the list of port management parameters supported by the DS-TT in the port management capability IE of the MANAGE PORT COMPLETE message;

b) if the operation code is "read parameter", attempt to read the value of the parameter at the DS-TT port, and:

1) if the value of the parameter at the DS-TT port is read successfully, include the parameter and its current value in the port status IE of the MANAGE PORT COMPLETE message; and

2) if the value of the parameter at the DS-TT port was not read successfully, include the parameter and associated port management service cause value in the port status IE of the MANAGE PORT COMPLETE message;

c) if the operation code is "selective read parameter", attempt to read the value of the selected sub-parameter(s) of the parameter at the DS-TT port, and:

1) if the value of the selected sub-parameter(s) at the DS-TT port is read successfully, include the parameter with the selected sub-parameter(s) and their current value in the port status IE of the MANAGE PORT COMPLETE message; and

2) if the value of the selected sub-parameter(s) at the DS-TT port was not read successfully, include the parameter and associated port management service cause value in the port status IE of the MANAGE PORT COMPLETE message;

d) if the operation code is "set parameter", attempt to set the value of the parameter at the DS-TT port to the value specified in the operation, and:

1) if the value of the parameter at the DS-TT port is set successfully, include the parameter and its current value in the port update result IE of the MANAGE PORT COMPLETE message; and

2) if the value of the parameter at the DS-TT port was not set successfully, include the parameter and associated port management service cause value in the port update result IE of the MANAGE PORT COMPLETE message;

NOTE 1: The value and status at the DS-TT of any optional sub-parameter not included in a parameter value field associated with operation code "set parameter" in the port management list IE of the MANAGE PORT COMMAND remains unchanged.

e) if the operation code is "subscribe-notify for parameter", store the request from the TSN AF to be notified of changes in the value of the corresponding parameter;

f) if the operation code is "selective subscribe-notify for parameter", store the request from the TSN AF to be notified of changes in the value of the corresponding selected sub-parameter(s) of the parameter;

g) if the operation code is "unsubscribe for parameter", delete the stored request from the TSN AF to be notified of changes in the value of the corresponding parameter, if any;

h) if the operation code is "selective unsubscribe for parameter", delete the stored request from the TSN AF to be notified of changes in the value of the corresponding selected sub-parameter(s) of the parameter, if any;

NOTE 2: If the operation code is "subscribe for parameter", the request from the TSN AF to be notified of changes in the value of the parameter is stored for each individual sub-parameter of the parameter. If the operation code is "selective unsubscribe for parameter", the stored requests from the TSN AF to be notified of changes in the value of sub-parameters are deleted only for the sub-parameters included in the parameter value field. If the operation code is "unsubscribe for parameter", the stored requests from the TSN AF to be notified of changes in the value of sub-parameters are deleted for all sub-parameters of the parameter.

i) if the operation code is "delete parameter-entry", attempt to delete the referred parameter-entry of the parameter at the DS-TT port; and

1) if the parameter-entry of the parameter at the DS-TT port is deleted successfully, include the parameter and its current value in the port update result IE of the MANAGE PORT COMPLETE message; and

2) if the parameter-entry of the parameter at the DS-TT port was not set successfully, include the parameter and associated port management service cause value in the port update result IE of the MANAGE PORT COMPLETE message; and

j) send the MANAGE PORT COMPLETE to the TSN AF via the SMF and the PCF as specified in 3GPP TS 23.502 [3].

5.2.1.4 Abnormal cases on the network side

The following abnormal cases can be identified:

a) T100 expired.

The TSN AF shall, on the first expiry of the timer T100, retransmit the MANAGE PORT COMMAND message and shall reset and start timer T100. This retransmission is repeated four times, i.e. on the fifth expiry of timer T100, the TSN AF shall abort the procedure.

5.2.1.5 Abnormal cases in the DS-TT

The following abnormal cases can be identified:

a) Transmission failure of the MANAGE PORT COMPLETE message indication from lower layers.

The DS-TT shall not diagnose an error and consider the network-initiated port management procedure complete.

NOTE: Considering the network-initiated port management procedure complete as a result of this abnormal case does not cause the DS-TT to revert the execution of the operations included in the MANAGE PORT COMMAND message.

5.2.2 DS-TT-initiated port management procedure

5.2.2.1 General

The purpose of the DS-TT-initiated port management procedure is to notify the TSN AF of one or more changes in the value of port management parameters for which the TSN AF had requested to be notified of changes via the network-initiated port management procedure.

5.2.2.2 DS-TT-initiated port management procedure initiation

In order to initiate the DS-TT-initiated port management procedure, the DS-TT shall create a PORT MANAGEMENT NOTIFY message and shall:

a) include the port management parameters to be reported to the TSN AF with their current value in the port status IE of the PORT MANAGEMENT NOTIFY message;

b) start timer T200; and

c) send the PORT MANAGEMENT NOTIFY message to the TSN AF via the SMF and the PCF as specified in 3GPP TS 23.502 [3].

Figure 5.2.2.2.1: DS-TT-initiated port management procedure

5.2.2.3 DS-TT-initiated port management procedure accepted by the TSN AF

Upon receipt of the PORT MANAGEMENT NOTIFY message, the TSN AF shall:

a) create a MANAGE PORT MANAGEMENT NOTIFY ACK message; and

b) send the MANAGE PORT MANAGEMENT NOTIFY ACK message to the UE via the PCF and the SMF as specified in 3GPP TS 23.502 [3].

5.2.2.4 DS-TT-initiated port management procedure completion

Upon receipt of the PORT MANAGEMENT NOTIFY ACK message, the DS-TT shall:

a) stop timer T200;

b) create a PORT MANAGEMENT NOTIFY COMPLETE message; and

c) send the PORT MANAGEMENT NOTIFY COMPLETE message to the TSN AF via the SMF and the PCF as specified in 3GPP TS 23.502 [3].

5.2.2.5 Abnormal cases on the network side

The following abnormal cases can be identified:

a) Transmission failure of the PORT MANAGEMENT NOTIFY ACK indication from lower layers.

The TSN AF shall not diagnose an error and consider the DS-TT-initiated port management procedure complete.

5.2.2.6 Abnormal cases in the DS-TT

The following abnormal cases can be identified:

a) T200 expired.

The DS-TT shall, on the first expiry of the timer T200, retransmit the PORT MANAGEMENT NOTIFY message and shall reset and start timer T200. This retransmission is repeated four times, i.e. on the fifth expiry of timer T200, the DS-TT shall abort the procedure.

b) Transmission failure of the PORT MANAGEMENT NOTIFY COMPLETE message indication from lower layers.

The DS-TT shall not diagnose an error and consider the DS-TT-initiated port management procedure complete.

5.2.3 DS-TT-initiated port management capability procedure

5.2.3.1 General

The purpose of the DS-TT-initiated port management capability procedure is to provide the DS-TT supported port management capabilities to the TSN AF during PDU session establishment as specified in 3GPP TS 23.502 [3].

5.2.3.2 DS-TT-initiated port management capability procedure

In order to initiate the DS-TT-initiated port management capability procedure, the DS-TT shall create a PORT MANAGEMENT CAPABILITY message and shall:

a) include the DS-TT port management capabilities in the port management capability IE of the PORT MANAGEMENT CAPABILITY message; and

b) send the PORT MANAGEMENT CAPABILITY message to the TSN AF via the SMF and the PCF as specified in 3GPP TS 23.502 [3].

Figure 5.2.3.2.1: DS-TT-initiated port management capability procedure