This topic describes how to use Web LCT to configure a physical clock.
Configuration Principles
To ensure the effect of clock tracing, comply with the principles of clock configuration.
Configuration Process
This topic describes the process of clock configuration based on a flowchart.
Configuring the Frequency Source Mode
Based on the actual networking situation, configure the frequency source mode of an NE before configuring a clock.
Configuring Attributes of Transport Clock for Boards
For clock synchronization, clock signals of a site must be transmitted to the downstream site and clock attributes (including Service Type and Synchronous Clock Enabled) must be configured for the boards.
Configuring External Port Cascading Mode for Clock Boards
The external port of a clock board can be used to connect the external time. In addition, the external port can be used for the concatenation of the clock boards within a multi-subrack NE.
Configuring Phase-Locked Source Output of External Clocks
When a clock signal passes through 10 or more NEs, frequency offset and drift may occur. As a result, the clock signal transmitted to the downstream NE is degraded. To prevent this from happening, a 2M phase-locked source must be used to optimize the clock signal.
Configuring the System Clock Source Priority Table
Configuring the system clock source priority table is actually to specify the priority of each required clock source. This provides a criterion for selecting clock sources in the case of clock switching.
Configuring the Quality of Clock Sources
In a complex clock network, there may be some unknown clock sources. You can uniformly define these clock sources as unavailable clocks so that NEs do not trace wrong clock sources. The NE obtains their quality information automatically for clock sources that are allocated to an NE. Define the quality level of clock sources only during test and maintenance.
Configuring the Clock Source Reversion Parameter
When there are multiple clock sources for an NE, set the clock sources to automatic reversion mode, so that the deteriorated clock source automatically becomes the traceable timing reference after it recovers.
Configuring the SSM Protocol
In a complicated clock network, you need to configure the clock protection for all NEs. After you set the clock source and specify the clock priority level for the NEs, you can enable the standard SSM or extended SSM protocol to prevent the NEs from tracing an incorrect clock source. This is how the clocks are protected.
Configuring the SSM Output
If the standard SSM or extended SSM protocol is enabled, the clock signals carry SSM messages automatically. You can prevent clock sources from sending SSM messages to other clock subnets. This helps you to ensure that the equipment of different clock subnets does not affect each other at the edge of clock networks.
Viewing Clock Synchronization Status
If the clocks between NEs in the network are not synchronous, the pointer justification, bit error, even service interruption may occur on NE. Using the Web LCT, you can learn and monitor the synchronization status of the NE clocks.
Configuring Switching Conditions for Clock Sources
If the traceable clock source of an NE is line clock, you can customize switching conditions for the clock source, so that the NE switches to other clocks when the clock source fails. In this manner, services are less affected.
Enabling Clock Source Switching
Enabling or disabling the clock source switching function for a configured clock source is actually a process of unlocking or locking the clock source.
Switching a Clock Source
When the traceable clock source in a network deteriorates, NEs may not be able to execute a switch on the clock source. You need to manually switch the clock source to prevent clock deterioration from affecting the normal running of NEs.