01-05 configuring clocks

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5 Configuring ClocksAbout This Chapter

A clock is the basis for the normal running of NEs. You must configure clocks for all NEs prior

to configuring services. In addition, you need to configure clock protection for complex

networks.

Prerequisite

NEs and boards must be created.

Context

To query the clock synchronous status for NEs in batches, select multiple NEs in the Clock

View, right-click and choose Query Clock Synchronous Status. You can understand the clock

synchronous status of NEs from the descriptions in legends. To configure NE clocks, perform

the following process:

5.1 Viewing Clock Synchronization Status

If the clocks between each NE in the network are not synchronous, the pointer justification, bit

error, even service interruption may occur on NE. Using the T2000, you can monitor and learn

the synchronization status of the NE clocks. The following procedures describe how to query

the clock synchronization status.

5.2 Viewing Clock Trace Search

Correct clock trace relations are critical to ensure the clock synchronization within the entire

network. Using the T2000, you can monitor the clock trace status of each NE. The following

procedures describe how to query the clock trace status.

5.3 Setting the NE Clock Source

Before configuring services, you must configure the NE clock source and specify the priority

level to ensure that correct clock trace relations are created for all the NEs in the network.

5.4 Setting Clock Source Protection

In complex clock networks, the synchronization status message (SSM) or extended SSM

protocol prevents the incorrect traceable clock source. After setting a clock source for an NE

and specifying the clock priority level, you need to enable the SSM or extended SSM protocol

to provide protection for clocks. In a complicated clock network, you need to configure the clockprotection for all NEs. After you set the clock source and specify the clock priority level for the

OptiX iManager T2000

Operation Guide for SDH 5 Configuring Clocks

Issue 01 (2007-09-15) Huawei Technologies Proprietary 5-1


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NEs, you can enable the SSM or extended SSM protocol to prevent the NEs from tracing an

incorrect clock source. This is how the clocks are protected.

5.5 Setting 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. Thus, thisdoes not affect services.

5.6 Setting Clock Source Reversion

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.

5.7 Setting Bound Clock Optical Path

When multiple pairs of fibers exist between two NEs, clock interlock may occur. To avoid this

problem, you must create protection for clock optical paths between NEs by binding clock optical

paths.

5.8 Preventing Clock Signal DegradeWhen clock signals are transmitted over 14 NEs or more, frequency offset and drift can occur.

To prevent clock signal degrade, you need to set 2 Mbit/s phase-locked source to optimize the

clock signals. For OSN equipment, you can also set 2M Phase-Locked Source External Clock

Attributes.

5.9 Setting the Phase-Locked Source for External Clock Output

When a clocksignal passes 14 or more NEs, frequency offset and drift may occur. To avoid

clock signal degrade, you need to set a 2 Mbit/s phase-locked source to optimize the clock signal.

For the OptiX OSN equipment, you can set 2M Phase-Locked Source External Clock Attributes.

5.10 Setting Clock Source Quality

In a complex clock network, there may be some unknown clock sources. You can uniformlydefine 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. You should define the quality level of clock sources only during test and maintenance.

5.11 Setting SSM Output

If the synchronization status message (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 do not affect each other at the edge of clock networks.

5.12 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 clockdeterioration from affecting the normal running of NEs.

5 Configuring Clocks


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5.1 Viewing Clock Synchronization Status

If the clocks between each NE in the network are not synchronous, the pointer justification, bit

error, even service interruption may occur on NE. Using the T2000, you can monitor and learn

the synchronization status of the NE clocks. The following procedures describe how to query

the clock synchronization status.

Prerequisite

You must be an NM user with "NE and network monitor" authority or higher.

Procedure

Step 1 In the NE Explorer, click an NE and choose Configuration > Clock> Clock Synchronization

Status from the Function Tree.

Step 2 ClickQuery to query the clock synchronization status.

----End

5.2 Viewing Clock Trace Search

Correct clock trace relations are critical to ensure the clock synchronization within the entire

network. Using the T2000, you can monitor the clock trace status of each NE. The following

procedures describe how to query the clock trace status.

Prerequisite

You must be an NM user with "NE and network operator" authority or higher.

Procedure

Step 1 Choose Configuration > Clock View from the Main Menu.

Step 2 In the Clock View, right-click and choose Synchronize NE Coordinate, the Prompt dialogbox is displayed. ClickOK.

Step 3 In the Clock View, right-click and choose Clock Trace Search.

Step 4 The OKdialog box is displayed, asking you whether to restore the NE coordinates saved lasttime when you saved the Clock View. ClickOK.

Step 5 If the clock trace relation changes, the Prompt dialog box is displayed, asking you whether torefresh the clock trace relation. ClickOK. When the search for the clock trace relation is

complete, the Clock View displays the refreshed clock trace status.

NOTE

If you select Disable Prompting Next Time, the Prompt dialog box is not displayed even when the clock

trace relation changes.

----End





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5.3 Setting the NE Clock Source

Before configuring services, you must configure the NE clock source and specify the priority

level to ensure that correct clock trace relations are created for all the NEs in the network.

Prerequisite


Context

To implement clock protection, you must configure at least two traceable clock sources for the

equipment. Usually, the tributary clock is not used as the clock source for the equipment.

After you set the clock sources for all the NEs, query the networkwide clock trace status again.

Procedure

Step 1 In the NE Explorer, select an NE and choose Configuration > Clock> Clock Source PriorityList from the Function Tree.

Step 2 ClickQuery to query the clock source.

Step 3 ClickCreate to display the Add Clock Source dialog box.

Step 4 Select a clock source and clickOK.

NOTE

l Select more than one clock source by holding the Ctrl key.

l If the clock trace relation changes because of the clock source change, the Prompt dialog box is

displayed, asking you whether to refresh the clock trace relation. Usually you can clickOK. If you

select Disable Prompting Next Time, the Prompt dialog box is not displayed even when the clock

trace relation changes.

Step 5 Optional: If an external clock source is selected, select External Clock Source Mode accordingto the type of external clock signals. For 2 Mbit/s clocks, specify the bytes to deliver SSM

message.

Step 6 Select a clock source, and click or to adjust its priority level. The clocksources are arranged in the descending order. The clock source on top is the preferred one for

the NE.

NOTE

Internal clock sources have the lowest priority because of their low precision.

Step 7 ClickApply.






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A prompt appears telling you that the operation was successful.

Step 8 ClickClose.

----End

5.4 Setting Clock Source Protection

In complex clock networks, the synchronization status message (SSM) or extended SSM

protocol prevents the incorrect traceable clock source. After setting a clock source for an NE

and specifying the clock priority level, you need to enable the SSM or extended SSM protocol

to provide protection for clocks. 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 SSM or extended SSM protocol to prevent the NEs from tracing an

incorrect clock source. This is how the clocks are protected.

PrerequisiteYou must be an NM user with "NE and network operator" authority or higher.

Procedure


Step 2 In the Clock View, right-click an NE and choose Clock Subnet Settings.

Step 3 Click the Clock Subnet tab. ClickQuery to query the parameter settings.

Step 4 Select Start Standard SSM Protocol orStart Extended SSM Protocol.





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NOTE

l The same SSM protection protocol must be used within the same clock protection subnet.

l The standard SSM is a mechanism used for the synchronization management in an SDH network. It is

loaded in the lower four bits of the S1 byte in SDH overheads. By allowing for the exchange of the

quality information of clock source among nodes, SSM ensures that the equipment automaticallychooses the clock source of the highest quality and priority to prevent clock mutual tracing. The SSM

protocol can be used in the interconnection with other vendors' equipment.

l The extended SSM brings forward the concept of clock source ID based on the standard SSM. It uses

the higher four bits of the S1 byte to define a unique ID for the clock trace, and is transmitted with the

standard SSM together. When a node receives the S1 byte, it checks whether the clock source ID defined

in the higher four bits originates from this station. If so, the clock source is unavailable. This scheme

prevents the clock from mutual tracing when the clock tracing trail is configured as a ring. The extended

SSM protocol is primarily used in the interconnection between Huawei equipment.

Step 5 Set the subnet number of the clock subnet to which the NE is associated. Assign the same subnetnumber to the NEs that have the same traceable clock source.

NOTE

l Set the clock subnet number to identify the clock subnet that an NE belongs to.

l When dividing clock subnets, divide the NEs that have the same traceable clock source to the same

subnet. The clock source is referred to as the subnet clock source. The division of clock subnets complies

with the principle of "The clock traceable chain cannot be too long" (not more than 20 NEs), to avoid

clock precision degrade.

Step 6 Optional: If the extended SSM protocol starts, set the clock ID of the clock source.

Step 7 ClickApply.

A prompt appears telling you that the operation was successful.

Step 8 ClickClose.

Step 9 Optional: If the clock ID is specified for the line clock of an NE, click the Clock ID Status tab,and set the Enabled Status to Enabled. ClickApply.

----End

5.5 Setting 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. Thus, this

does not affect services.

Prerequisite


Procedure

Step 1 In the NE Explorer, select an NE and choose Configuration > Clock> Clock SourceSwitching from the Function Tree. Click the Clock Source Switching Condition tab.

Step 2 ClickQuery to query the parameter settings.

Step 3 Double-click the parameters to set clock switching conditions.






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Step 4 ClickApply.

A prompt is displayed telling you that the operation was successful.

Step 5 ClickClose.

----End

5.6 Setting Clock Source Reversion

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.

Prerequisite


Procedure


Step 2 In the Clock View, right-click an NE and choose Clock Source Reversion Parameter.

Step 3 Optional: Choose Configuration > Batch Clock Operation from the Main Menu. Click theClock Source Reversion Parameter tab. From the Object Tree on the left-hand pane, select an

NE and click .

Step 4 Double-click and set the reversion mode and the WTR time.

NOTE

l Do not set Clock Source WTR Time(min) to 0 to avoid repeated switching when the clock is unstable.

l You can configure clocks for multiple NEs at the same time by batch operations.

Step 5 ClickApply.


Step 6 ClickClose.


----End





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5.7 Setting Bound Clock Optical Path

When multiple pairs of fibers exist between two NEs, clock interlock may occur. To avoid this

problem, you must create protection for clock optical paths between NEs by binding clock optical

paths.

Prerequisite

l You must be an NM user with "NE and network operator" authority or higher.

l Applies to the OptiX 2500+(Metro 3000).

Procedure

Step 1 In the NE Explorer, click an NE and select Configuration > Clock> Bound Clock OpticalPath from the Function Tree.

Step 2 ClickNew. The Create a Bound Clock Optical Path Group dialog box is displayed.

Step 3 Select the optical ports to bind, and click to add them to group

NOTE

Select at least two optical ports for binding optical paths.

Step 4 ClickOK. The Operation Result dialog box is displayed and indicates that operation succeeded.

Step 5 ClickClose.

Step 6 Optional: Select the created bound clock optical path group, ClickModify and repeat steps 3to 5 to modify the attribute of bound clock optical path group.

----End

5.8 Preventing Clock Signal Degrade

When clock signals are transmitted over 14 NEs or more, frequency offset and drift can occur.To prevent clock signal degrade, you need to set 2 Mbit/s phase-locked source to optimize the






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clock signals. For OSN equipment, you can also set 2M Phase-Locked Source External Clock

Attributes.

Prerequisite


Procedure


Step 2 In the Clock View, right-click an NE icon and choose Phase-Locked Source Output byExternal Clock.

Step 3 ClickQuery to query parameter settings.

Step 4 Set appropriate values for the parameters.

Step 5 ClickApply.A prompt is displayed telling you that the operation was successful.

Step 6 ClickClose.

----End

5.9 Setting the Phase-Locked Source for External ClockOutput

When a clock signal passes 14 or more NEs, frequency offset and drift may occur. To avoid

clock signal degrade, you need to set a 2 Mbit/s phase-locked source to optimize the clock signal.

For the OptiX OSN equipment, you can set 2M Phase-Locked Source External Clock

Attributes.

Prerequisite


Procedure


Step 2 In the Clock View, right-click an NE and choose Phase-Locked Source Output by ExternalClock.

Step 3 Optional: ClickExternal Clock Output Phase-Locked Source.

Step 4 Optional: Click2M Phase-Locked Source External Clock Attributes.


Step 6 Set parameters and then clickApply.


Step 7 ClickClose.

----End





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5.10 Setting Clock Source Quality

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. You should define the quality level of clock sources only during test and maintenance.

Prerequisite


Procedure


Step 2 In the Clock View, right-click an NE and choose Clock Subnet Setting from the shortcut menu.Click the Clock Quality tab.


Step 4 Click the Clock Source Quality tab and set Configuration Quality to AutomaticExtraction.

Step 5 ClickApply.


Step 6 ClickClose.

Step 7 Click the Manual Setting of 0 Quality Level tab. Set Manual Setting of 0 Quality Level toSynchronous Source Unavailable.

NOTE

Batch operation is supported in the Manual Setting of 0 Quality Level tab. Choose Configuration >

Batch Clock Operation from the Main Menu. Click the Manual Setting of 0 Quality Level tab, select

the NEs you want from the Object Tree on the left side, and click .

Step 8 ClickApply.

----End

5.11 Setting SSM Output

If the synchronization status message (SSM) or extended SSM protocol is enabled, the clocksignals carry SSM messages automatically. You can prevent clock sources from sending SSM






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messages to other clock subnets. This helps you to ensure that the equipment of different clock

subnets do not affect each other at the edge of clock networks.

Prerequisite


Procedure


Step 2 In the Clock View, right-click an NE and choose Clock Subnet Settings from the shortcut menu.Click the SSM Output Control tab.

Step 3 Set the control status of the clock source.

Step 4 ClickApply. A prompt is displayed telling you that the operation was successful.

Step 5 ClickClose.

Step 6ClickQuery to query the parameter value.

----End

5.12 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.

Prerequisite

l You must be an NM user with "NE and network operator" authority or higher.





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l The clock source has been created.

CAUTION

Performing clock source switching may cause service interruption.

Procedure


Step 2 In the Clock View, right-click an NE and choose Clock Source Switching.

Step 3 ClickQuery to query the switching status of a clock source.

Step 4 Optional: If the Lock Status is Lock, right-click and choose Unlock.

Step 5 Right-click the clock source that you want to switch and choose a switching operation.

NOTE

Before switching the clock source, make sure that the new clock source that is not locked and that is of a

good quality is created in the priority table.

Step 6 Optional: To restore the automatic clock source selection mode, right-click the switched clocksource and choose Clear Switching.

----End





01-05 configuring clocks

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