K.2.2.4 Configuration for PTP grandmaster function

The following options may be supported (per DS-TT) for the 5GS to generate the Sync, Follow_Up and Announce messages for the Leader ports on the DS-TT:

• NW-TT generates the Sync, Follow_Up and Announce messages on behalf of DS-TT (e.g. if DS-TT does not support this).
• DS-TT generates the Sync, Follow_Up and Announce messages in this DS-TT.

TSN AF and TSCTSF may use the elements in port and user plane node management information container to determine the PTP grandmaster functionality supported by DS-TT and NW-TT and may configure the DS-TT and NW-TT ports to operate as in option a) or b) as follows:

• The "PTP grandmaster capable" element and the "gPTP grandmaster capable" element in PMIC are used to indicate the support for PTP or gPTP grandmaster capability, respectively, in each DS-TT. If the TSN AF or TSCTSF determines the DS-TT supports grandmaster capability (PTP or gPTP grandmaster capable is TRUE), then either option a) or b) can be used for the PTP instance(s) in the DS-TT. Otherwise, only option a) can be used for the PTP instance(s) in the DS-TT.
• To enable option a) for PTP ports in DS-TT, the TSN AF or TSCTSF sets the element "Grandmaster on behalf of DS-TT enabled" TRUE (per PTP instance per DS-TT) in UMIC for the respective DS-TT port and the TSN AF or TSCTSF sets the element "Grandmaster enabled" FALSE (per PTP instance per DS-TT) in PMIC to the respective DS-TT port.
• To enable option b) for PTP ports in DS-TT, the TSN AF or TSCTSF sets the element "Grandmaster on behalf of DS-TT enabled" FALSE in UMIC (per PTP instance per DS-TT) for the respective port and the TSN AF or TSCTSF sets the element "Grandmaster enabled" TRUE (per PTP instance per DS-TT) in PMIC to the respective DS-TT port.
• To enable either option a) or option b) for a PTP instance, the TSN AF or TSCTSF sets the element "Grandmaster candidate enabled" TRUE (per PTP instance) in UMIC.
• When option b) is used for one or more PTP ports in DS-TT(s), the TSN AF or TSCTSF shall use the elements in defaultDS in PMIC for the respective DS-TT(s) and in UMIC for NW-TT to ensure that all PTP ports in the DS-TT(s) and NW-TT in particular PTP instance are distributing the same values of grandmasterPriority1, grandmasterClockQuality, grandmasterPriority2, grandmasterIdentity and timeSource message fields in Announce messages.