31:16

0h

RO

Reserved (RSVD_​M)

Reserved.

15:8

4h

RW/O

Local Clock Granularity (LCG)

0000 0000b: Time Source does not implement a local clock. It simply propagates timing information obtained from further Upstream in the PTM Hierarchy when responding to PTM Request messages.

0000 0001b - 1111 1110b: Indicates the period of this Time Source's local clock in ns.

1111 1111b: Indicates the period of this Time Source's local clock is greater than 254 ns.

If the PTM Root Select bit is Set, this local clock is used to provide PTM Master Time. Otherwise, the Time Source uses this local clock to locally track PTM Master Time received from further Upstream within a PTM Hierarchy.

7:5

0h

RO

Reserved

4

1h

RW/O

PTM Propagation Delay Adaptation Capable (PTMPDAC)

When Set, this field indicates the Port supports the PTM Propagation Delay Adaptation Capability.

3

0h

RO

Reserved

2

0h

RW/O

PTM Root Capable (PTMRC)

Root Ports must set this bit to 1b.

1

0h

RW/O

PTM Responder Capable (PTMRSPC)

Root Ports are permitted to set this bit to 1b to indicate that they implement the PTM Responder role.

0

0h

RO

PTM Requester Capable (PTMREQC)

PTM Requester Role is not supported by Root Port.