Configuring Clock Source Attributes Used for Dynamic BMC Selection
This section describes how to configure clock source attributes used for dynamic BMC selection. SMPTE-2059-2 devices configured with clock source attributes can participate in BMC selection. The local clock on a SMPTE-2059-2 device can also participate in BMC selection. The BMC algorithm 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 BMC algorithm 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 the 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 the clock-class.
Perform the following steps on each router connected to an external BITS source on the SMPTE-2059-2 network:
Procedure
- Run system-view
The system view is displayed.
- Run ptp clock-source { local time-source time-source-value | [ chassis chassis-id ] { bits0 | bits1 | bits2 } time-source time-source-value [ slot slot-id ] }
The type of the clock source to be tracked is specified.
This command can be run only on the grandmaster. For information about the mapping between time-source-value values and clock sources, see Table 1 of ptp clock-source in NE40E - Command Reference.
- Run ptp clock-source { local clock-accuracy clock-accuracy-value | [ chassis chassis-id ] { bits0 | bits1 | bits2 } clock-accuracy clock-accuracy-value [ slot slot-id ] }
The accuracy of the clock source is configured.
For information about the mapping between clock-accuracy-value values and clock accuracy specifications, see Table 2 of ptp clock-source in NE40E - Command Reference.
- Run ptp clock-source { local clock-class clock-class-value | [ chassis chassis-id ] { bits0 | bits1 | bits2 } clock-class clock-class-value [ slot slot-id ] }
The class of the clock source is specified.
For information about the mapping between clock-class-value values and clock class specifications, see Table 3 of ptp clock-source in NE40E - Command Reference.
If the value of clock-class-value is less than 128, the router cannot function as a slave clock.
- Run ptp clock-source { local priority1 priority1-value | [ chassis chassis-id ] { bits0 | bits1 | bits2 } priority1 priority1-value [ slot slot-id ] }
Priority1 is specified for the clock source.
- Run ptp clock-source { local priority2 priority2-value | [ chassis chassis-id ] { bits0 | bits1 | bits2 } priority2 priority2-value [ slot slot-id ] }
Priority2 is specified for the clock source.
- (Optional) Run ptp clock-source [ chassis chassis-id ] { bits0 | bits1 | bits2 } grandmaster-clockid grandmaster-clockid-value [ slot slot-id ]
The grandmaster clock ID is specified for the clock source.
- (Optional) Run ptp clock-source [ chassis chassis-id ] { bits0 | bits1 | bits2 } offsetscaled-logvariance offsetscaled-logvariance-value [ slot slot-id ]
The offset scaled log variance is specified for the clock source.
- Run commit
The configuration is committed.
