Configuring Clock Source Attributes for Dynamic BMC Selection

After multiple SMPTE-2059-2 devices are configured with BITS signal input, clock source attributes can be configured on these devices to allow them to participate in BMC selection. The local clock of an SMPTE-2059-2 device can also participate in BMC selection. The BMC algorithm (BMCA) helps SMPTE-2059-2 devices dynamically determine the grandmaster clock which provides time signals for the entire SMPTE-2059-2 network. SMPTE-2059-2 devices can obtain clock synchronization information from the grandmaster clock through the SMPTE-2059-2 protocol.

Context

When an SMPTE-2059-2-enabled router uses the BMCA to dynamically select a clock source, the router compares the following parameters in sequence: priority1 > clock-class > clock-accuracy > priority2. That is, the router preferentially compares priority1 of clock sources. The clock source with the largest value of priority1 is selected as the grandmaster clock. If the priority1 values are the same, the router then compares clock-class.

Perform the following steps on each router connected to an external BITS source on an SMPTE-2059-2 network:

Procedure

Run system-view
The system view is displayed.
Configure the type of the clock source to be traced.
The local clock and BITS1 signals are used as an example. The actual number of BITS interfaces and their IDs depend on the hardware configuration.
```
ptp clock-source { local time-source time-source-value | bits1 time-source time-source-value }
```
This command applies only to the grandmaster. The parameter settings vary according to the type of the clock source. For the mapping between time-source-value and the clock source type, see ptp clock-source in the NetEngine 8000 F Command Reference.
Run ptp clock-source { local clock-accuracy clock-accuracy-value | bits1 clock-accuracy clock-accuracy-value }
The clock accuracy of the clock source is configured.

For the mapping between clock-accuracy-value and the clock accuracy, see ptp clock-source in the NetEngine 8000 F Command Reference.
Run ptp clock-source { local clock-class clock-class-value | bits1 clock-accuracy clock-class-value }
```
The clock class of the clock source is configured.
```
For the mapping between clock-class-value and the clock source level, see ptp clock-source in the NetEngine 8000 F Command Reference.

If the value of clock-class-value is less than 128, the device cannot function as a slave clock.
Run ptp clock-source { local priority1 priority1-value | bits1 priority1 priority1-value }
The priority1 of the clock source is configured.
Run ptp clock-source { local priority2 priority2-value | bits1 priority2 priority2-value }
The priority2 of the clock source is configured.
(Optional) Run ptp clock-source bits1 grandmaster-clockid grandmaster-clockid-value
The grandmaster clock ID of the clock source is configured.
(Optional) Run ptp clock-source bits1 offsetscaled-logvariance
The stability of the clock source is configured.
Run commit
The configuration is committed.