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Wavelength Protection Switch Solutions

 

The WPS4 (BT8A78WPS4) provides 1+1 revertive or non-revertive optical protection switching.

Four wavelength protection groups can be provisioned on one module.

WPS4 modules function in a bookended configuration with one WPS4 being provisioned at the local node and one at the remote node.

A wavelength protection group consists of 3 ports (Cnout / in, LnAout / in, LnBout / in) as shown in the diagram above.

At the local node, the signal received at the Cnin port is split into two identical signals and transmitted out the LnAout and LnBout ports. These signals are received at the LnAin and LnBin ports at the remote node where an internal optical switch selects one of the incoming signals based on optical power levels. The selected signal is then transmitted out the Cnout port.

Traffic transmitted from the remote node to the local node is handled in the same manner.

The path between the two LnA ports is called the working path. The path between the two LnB ports is called the protecting (or protection) path. Either path can be active. An incoming path is active if its signal is selected by the internal optical switch. The other path is in standby. Only one path can be active at any given time.

Note

Paths are unidirectional. For example, the working path can be active in one direction and standby in the opposite direction.

Should a fault occur on the active path causing the received power to fall below the loss of light threshold, an automatic protection switch occurs. After the fault has been cleared, traffic continues to be selected from the active path unless the group is configured for revertive switching. In revertive switching, traffic reverts to the working path (LnA) when the wait-to-revert time expires. In this case, if traffic is already on the working path, it remains on the working path.

The WPS4 provides the following functionality:

  • Can protect a single wavelength or multiple wavelengths

  • Supports operation on the following bands:

    • For extended C-band operation covering 1500 to 1570 nm

    • For L-band operation covering 1560 to 1620 nm

    • For O-band operation covering 1260 to 1360 nm

  • Broadcast launch via a splitter to active and standby paths

  • Active path selection via latching optical switch

  • Automatic switching based upon received power levels

  • Manual switching based upon provisioned switch state

  • Monitoring of all input power levels

WPS4 Protection and Rapid Restoration Configurations

The WPS4 supports the following applications:

  • Optical Protection Switching - In Optical Protection Switching configurations, WPS4 protection switching operates within 50 ms of fault detection to ensure a minimum disruption of service. See Table 1.

  • Rapid Restoration - In Rapid Restoration configurations, the time taken to restore traffic is dictated by the APSD or APR control systems between the local and remote WPS4. Therefore 50 ms protection switching is not guaranteed. The system will quickly and automatically restore service as soon as these controls resolve. This is typically in the order of seconds. See Table 2.

Table 1: WPS4 Protection Switching Configurations

Optical Protection Switching Configurations

LoLightRx Threshold

Unamplified line protection

Default

Unamplified channel protection

Default

Amplified line protection with unamplified protection path

Default

Amplified channel protection with amplified protection path

Customized

Table 2: WPS4 Rapid Restoration Configurations

Rapid Restoration Configurations

LoLightRx Threshold

Amplified line restoration with unamplified protection path

Default

Amplified line restoration with amplified protection path

Default

If the optical solution you wish to use is not listed, please contact Juniper Networks Support.

Wavelength Protection Switch Unamplified Line Protection

The following example shows how the WPS4 can provide unamplified line protection within a network.

The optical protection switch solution:

  • Is a simple system configuration with diverse network paths on working and protection fiber pairs

  • The default provisioning of the LoLightRx threshold (-35 dBm) should be used to protect for a fiber break on system fibers.

Note

This is the preferred configuration for unamplified systems as the optical multiplex section (OMS) is protected by a single protection group.

Wavelength Protection Switch Unamplified Channel Protection

The following example shows how the WPS4 can provide unamplified channel protection within a network.

The optical protection switch solution:

  • Provides per optical channel (OCh) protection configuration with diverse network paths on working and protection fiber pairs

  • The default provisioning of LoLightRx threshold (-35dBm) should be used to protect for a fiber break on system fibers.

Wavelength Protection Switch Amplified Line Protection with an Unamplified Protection Path

The following example shows how the WPS4 can provide amplified line protection with an unamplified protection path within a network.

The optical protection switch solution:

  • Is a simple system configuration with diverse network paths on working and protection fiber pairs

    • Amplification allows for extended link budgets with BTI7000 Series LGA/MGA/MGM amplifiers

  • The default provisioning of the LoLightRx threshold (-35dBm) should be used to protect for a fiber break on system fibers

  • Losses on Working and Protection paths should be balanced to within 2dB to avoid the need for amplifier gain adjustments after a protection event. This should be achieved by adding attenuation to the lowest loss path of the two

  • Care must be taken with booster amplifiers as a protection event might trigger APR in EDFA.

Note

This is the preferred configuration for amplified systems as the optical multiplex section (OMS) is protected by a single protection group.

Wavelength Protection Switch Amplified Channel Protection with an Amplified Protection Path

The following example shows how the WPS4 can provide amplified channel protection with an amplified protection path within a network.

The optical protection switch solution:

  • Is a simple system configuration with diverse network paths on working and protection fiber pairs

    • Amplification allows for extended link budgets.

    • Either or both paths can be amplified.

  • A 50-GHz DWDM operation is supported via ROB496 ROADM

  • A 100-GHz DWDM operation is supported via BTI7000 Series LGA/MGA/MGM optical amplifiers.

A custom provisioning of the WPS4's LoLightRx threshold is required when installing and provisioning the optical network. See Provisioning customized LoLight-Rx threshold

Wavelength Protection Switch Amplified Line Restoration with an Unamplified Protection Path

The following example shows how the WPS4 can provide amplified line restoration with an unamplified protection path.

The optical restoration switch solution:

  • Is a flexible system configuration with diverse network paths on working and protection fiber pairs

    • Amplification allows for extended link budgets with restoration supported using BTI7800 AMP1 amplifiers

  • Default provisioning of LoLightRx (-35 dBm) should be used to protect for a fiber break on system fibers

  • Losses on Working and Protection paths should be balanced to within 2dB avoid the need for amplifier gain adjustments after a protection event. This should be achieved by adding attenuation to the lowest loss path of the two.

Note

This is the preferred configuration for amplified systems as the optical multiplex section (OMS) is protected by a single protection group.

Wavelength Protection Switch Amplified Line Restoration with an Amplified Protection Path

The following example shows how the WPS4 can provide amplified line restoration with an amplified protection path.

The optical restoration switch solution:

  • Is a flexible system configuration with diverse network paths on working and protection fiber pairs

    • Amplification allows for extended link budgets using BTI7000 Series LGA/MGA/MGM optical amplifiers.

  • The default provisioning of LoLightRx (-35dBm) should be used to protect for a fiber break on system fibers.

  • The BTI7000 Series LGA/MGA/MGM optical amplifiers will turn off the output in the event of an input LOS event. The fault will propagate to the WPS4 as each downstream amp turns off. This might not complete within 50ms. Therefore this is Rapid Restoration rather than Protection. An automatic switch will still occur.

Note

It is possible to construct restoration solutions using the other amplifiers in the BTI Series portfolio but there are often deployment restrictions associated with these configurations. If these configurations are required, please contact Juniper Networks Support to evaluate your specific network requirement.

Provisioning Wavelength Protection Groups and Ports

Up to four wavelength protection groups can be provisioned on one module. A wavelength protection port can carry either a single wavelength or multiple wavelengths. The wavelength protection group number at the remote node is not required to match the wavelength protection group number of the WPS4 provisioned at the local node.

The wavelength protection ports are automatically created by the system when the group is provisioned. By default and under no line failures, LnA will be active.

LnA is the working port and LnB is the protecting port. This is a set configuration and cannot be changed.

The following table details the wavelength protection groups and their associated physical ports as detailed on Wavelength Protection Switch (WPS4) faceplate.

wavelength protection group

Associated wavelength protection group ports

wavelength protection group #1

C1 L1B L1A

wavelength protection group #2

C2 L2B L2A

wavelength protection group #3

C3 L3B L3A

wavelength protection group #4

C4 L4B L4A

The wavelength ports (Cn, LnA, LnB) cannot be created independently of the group, nor can they be deleted. To delete a wavelength port you must delete the wavelength protection group it belongs to.

When a wavelength protection group is unprovisioned or deleted, the three wavelength ports associated with the group will be automatically deleted and line port A will be forced active, regardless of the received power.

The wavelength ports do not support the ability to shut down the laser. When the ports are optically connected, the WPS4 is capable of passing light from the Cn OUT, LnA OUT and LnB OUT ports at all times. Even when the module is not powered or when the module is not installed in the chassis.

Note

The Loss of Light Receive threshold (LoLightRx) must be set according to the optical link budget in order for the protection switch to operate as per specification.

Provisioning Wavelength Protection Groups

Use this procedure to provision the wavelength protection groups on a WPS4.

  1. Provision the wavelength protection groups.

    The following examples show how to provision four wavelength protection groups on the WPS4.

    bti7800(config)# protection wavelength group wpsgroup:1/2/1
  2. Optional, provision revertive or non-revertive switching.

    The default is non-revertive. The following example shows how to provision revertive switching.

    bti7800(config-protection-wavelength-group-wpsgroup:1/2/4)# revertive-type revertive bti7800(config-protection-wavelength-group-wpsgroup:1/2/4)# commit bti7800(config-protection-wavelength-group-wpsgroup:1/2/4)#
  3. Optional, provision additional wavelength protection group parameters.

    At any wavelength protection group configuration mode, you can configure the parameters listed in the table below. See also the CLI command protection wavelength group.

    Parameter

    Description

    protid

    A user-defined identifier of the protection group.

    0 to 32 alphanumeric characters

    Default : An empty string

    Note: This identifier is not required to match the remote node.

    remote-protid

    A user-defined identifier of the remote protection group.

    0 to 32 alphanumeric characters

    Default : An empty string

    Note: This identifier is not required to match the remote node.

    custom

    User-defined string.

    0 to 255 alphanumeric characters

    Default : An empty string

  4. Verify the wavelength protection group provisioning is correct.

    Use the show protection wavelength group command to verify if the WPS4 provisioning is correct.

    bti7800# show protection wavelength group

You have successfully completed this procedure.

Related Commands

show running-config

show protection wavelength group table

Provisioning Wavelength Protection Ports

Use the following procedure to provision the wavelength protection ports on the WPS4.

  1. Provision the lolight-rxth

    The following example shows how to configure the loss of light threshold for each port in wavelength group.

    bti7800(config)# protection wavelength port wpsport:1/3/1/C1A lolight-rxth -25.0
    Note

    The lolight-rxth must be configured according to the optical link budget in order for the protection switch to operate as per specification. See also WPS4 protection and rapid restoration configurations and Provisioning customized LoLight-Rx threshold.

  2. Optional, provision additional wavelength port parameters.

    The following additional wavelength port parameters can be provisioned.

    Parameter

    Description

    id

    A user-defined identifier of the local wavelength protection port.

    0 to 32 alphanumeric characters

    Default : An empty string.

    Note: This identifier is not required to match the remote node.

    remote-id

    A user-defined identifier of the remote wavelength protection port.

    0 to 32 alphanumeric characters

    Default : An empty string.

    Note: This identifier is not required to match the remote node.

    custom

    User-defined string.

    0 to 255 alphanumeric characters

    Default : An empty string.

  3. Verify the wavelength port provisioning is correct.

    Use the show protection wavelength port command to verify if the wavelength protection port provisioning is correct.

    bti7800# show protection wavelength port
  4. Optional, view wavelength port statistics

    Use the show statistics command to view wavelength port statistics.

    bti7800# show statistics current wpsport:1/1/L1A

You have successfully completed this procedure.

Related Commands

show running-config

show protection wavelength port

Provisioning Customized LoLightRx Thresholds

Use this procedure to set customized LoLightRx thresholds. For additional information see WPS4 protection and rapid restoration configurations

Provisioning Customized LoLightRx Threshold

You will be required to provision customized LoLightRx thresholds in the following network configurations:

  • 50-GHZ DWDM networks deploying WPS4 channel protection with BTI7000 Series ROB496 ROADM

  • 100-GHz DWDM networks deploying WPS4 channel protection with BTI7000 Series LGA/MGA/MGM optical amplifiers.

Note

You might be required to provision the LoLightRx thresholds in network configurations which are not defined in WPS4 protection and rapid restoration configurations. Contact Juniper Networks Support if you require further information.

Note

In networks deploying WPS4 channel protection with BTI7000 Series LGA/MGA/MGM optical amplifiers, this procedure should also be performed every time there are significant changes to the channel powers. We recommend that you reset the LoLightRx threshold if the receive power of a channel changes by more than +/- 2.5dB.

Before beginning this procedure ensure the ROB496 ROADM or Amp and the WPS4s are installed, provisioned and are connected in the network. The wavelength protection groups must be provisioned. The ROB496 ROADM or Amp must be provisioned with the channels up. The protection and working paths must be alarm free.

  1. Note the received power on the wavelength protection ports LnA and LnB for the required channel.

    The following commands show examples of how to display the received power on L1A and L1B.

    bti7800# show statistics current wpsport:1/1/L1A
    bti7800# show statistics current wpsport:1/1/L1B
  2. Calculate the customized LoLightRx threshold values for LnA and LnB using the equations listed below.

    The following examples show how to calculate the LoLightRx thresholds.

    Example 1: Cn = ROB496 ROADM

    For example if the received power at LnA was -10 dBm and the received power at LnB was -15 dBm then the following applies:

    Customized LoLightRx threshold LnA = -10 dBm - 6 dB = -16 dBm
    Customized LoLightRx threshold LnB = -15 dBm - 6 dB = -21 dBm

    Example 2: Cn = BTI7000 Series LGA/MGA/MGM optical amplifiers

    For example if the received power at LnA was -10 dBm and the received power at LnB was -15 dBm then the following applies:

    Customized LoLightRx threshold LnA = -10 dBm - 4.5 dB = -14.5 dBm
    Customized LoLightRx threshold LnB = -15 dBm - 4.5 dB = -19.5 dBm
  3. Provision the LoLightRx thresholds for LnA and LnB.

    Example 1: Provisioning the LoLightRx thresholds for LnA and LnB when Cn = ROB496 ROADM

    bti7800(config)# protection wavelength port wpsport:1/1/1/L1A lolight-rxth -16.0

    Example 2: Provisioning the LoLightRx thresholds for LnA and LnB when Cn = BTI7000 Series LGA/MGA/MGM optical amplifiers

    bti7800(config)# protection wavelength port wpsport:1/1/1/L1A lolight-rxth -14.5
  4. Repeat this procedure for any other ports provisioned on the WPS4s.

Performing User-Invoked Switches on the WPS4

Manual Switch

A manual switch is applied to the active line and results in a switching traffic away from the active line to the current standby line. The standby line will then become the new active line. A manual switch is not permitted if the standby line has a loss of signal. A manual switch does not disable automatic switching and does not require to be released.

Forced Switch

A forced switch is applied to the active line and results in switching traffic away from the active line to the current standby line. The standby line will then become the new active line. A forced switch is permitted even if the standby line is not alarm free. A forced switch can be provisioned even when the WPS4 is not present. It will persist until it is released.

Lockout Switch

A lockout switch is applied to the standby line and results in preventing traffic from switching to the standby line. A lockout switch is permitted even if the standby line is not alarm free. A lockout switch can be provisioned even when the WPS4 is not present. It will persist until it is released.

Note

Lockout and forced protection switch provisioning will persist in the system database.

Note

The commit function is not required when performing a user-invoked switch.

Revertive and Non-revertive Wavelength Protection Switching

In revertive switch operation, traffic will switch back to the working line after the fault has cleared and the wait-to-revert time has elapsed. The wait-to-revert time is 600 seconds and cannot be changed. Automatic, manual, forced and lockout switches will revert after they are released if the active line after release is protecting line (LnB).

In non-revertive switch operation traffic will not switch back to the active line. The default is non-revertive.

Performing a Manual Wavelength Protection Switch

User-invoked wavelength protection switches can be performed either in the operational or configuration mode. The show protection wavelength group table is performed in the operational mode only.

Note

The commit function is not required when performing a user-invoked switch.

  1. Performing a manual wavelength protection switch

    The following example shows how to perform a manual switch when the currently active line is L1A.

    bti7800# protection wavelength switch manual wpsport:1/2/L1A

You have successfully completed this procedure.

Related Commands

show protection wavelength group table

Performing a Forced Wavelength Protection Switch

User-invoked wavelength protection switches can be performed either in the operational or configuration mode. The show protection wavelength group table is performed in the operational mode only.

A forced switch is performed on the active line and results in a switch away from the active line. The active line then becomes the standby line.

Note

The commit function is not required when performing a user-invoked switch.

  1. Performing a forced wavelength protection switch.

    The following example shows how to perform a forced switch when the currently active line is L1A.

    bti7800# protection wavelength switch forced wpsport:1/2/L1A
  2. Releasing a forced switch.

    The following example shows how to release a forced switch when the currently standby line is L1B.

    bti7800# protection wavelength switch release wpsport:1/2/L1B

You have successfully completed this procedure.

Related Commands

show protection wavelength group table

Performing a Lockout Wavelength Protection Switch

User-invoked wavelength protection switches can be performed either in the operational or configuration mode. The show protection wavelength group table is performed in the operational mode only.

A lockout switch is performed on the standby line and results in preventing traffic from switching to that line.

Note

The commit function is not required when performing a user-invoked switch.

  1. Performing a lockout switch

    The following example shows how to perform a lockout when the currently standby line is L2B:

    bti7800# protection wavelength switch lockout wpsport:1/2/L2B
  2. Releasing a lockout switch

    The following example shows how to release a lockout switch when the currently standby line is L2B:

    bti7800 # protection wavelength switch release wpsport:1/2/L2B

You have successfully completed this procedure.

Related Commands

show protection wavelength group table

Wavelength Protection Switch Alarms

Alarms and conditions can be viewed using the CLI. Autonomous notifications are available via NETCONF and SNMP.

The following alarms are supported on the WPS4:

  • Port alarms:

    • loLightRx

  • Module alarms:

    • eqptMiss

    • eqptMism

Wavelength Protection Switch Performance Monitoring

Performance monitoring is conducted on provisioned ports. Current and historical statistics are supported.

The types of physical layer performance monitoring parameters are listed in the following table:

Monitored Type

Montype

Description

Units

Optical Power Received

OPR

The power of the optical signal received on a port.

dBm

The optical power received on each port (Cn, LnA and LnB) is monitored and can be viewed using the CLI command show statistics.

An example is shown below.

bti7800# show statistics current wpsport:1/1/L1A