Configuring VOA Module Interfaces

Table Of Contents

Configuring VOA Module Interfaces

About Variable Optical Attenuation

VOA Modules

Configuring VOA Module Interfaces

Configuring Attenuation

Configuring Automatic Attenuation

Configuring Manual Attenuation

Displaying the Attenuation Configuration

About Optical Thresholds

Configuring Optical Receive Power Thresholds

Displaying the Optical Threshold Configuration

Configuring VOA Module Interfaces

This chapter describes how to configure the VOA modules supported by the Cisco ONS 15530. These modules allow the Cisco ONS 15530 to extend the internodal distances and number of nodes supported for point-to-point, hubbed ring, and meshed ring topology networks.

This chapter includes the following sections:

• About Variable Optical Attenuation

• Configuring VOA Module Interfaces

• Configuring Attenuation

• Displaying the Attenuation Configuration

• About Optical Thresholds

• Configuring Optical Receive Power Thresholds

About Variable Optical Attenuation

The attenuation typically occurs on the input side of the EDFA (erbium-doped fiber amplifier) so that the input power of each band transmitted to the EDFA is equalized. The VOA modules can also attenuate OSC channels, EDFA output (when preamplifying), or individual data channels.

The Cisco ONS 15530 supports two types of VOA modules:

•PB-OE (per-band optical equalizer) modules

•WB-VOA (wide-band variable optical attenuator) modules

A PB-OE module selects one or two bands of channels to attenuate and passes on the rest of the signal. By reading pass band after-attenuation power through the photo detector of the PB-OE module, the total power of the sum of the channels in the pass band will be obtained, from which the average power of an individual channel can be deduced if we assume they have been equalized. By monitoring the optical power of the PB-OE module, the total of the channels power of band is deduced by factoring the standard ranges of channels. WB-VOA modules attenuate all the channels it receives. The power reading through the photodetector of the WB-VOA module gives the total power of the signal after attenuation.

Figure 10-1 illustrates the use of PB-OE and WB-VOA modules to perform band based power equalization.

Figure 10-1 Four Band Equalization with Three Power Equalizers

VOA Modules

The VOA modules are half-width modules inserted into a carrier motherboard installed in a Cisco ONS 15530 shelf. The carrier motherboards can be installed in slots 1 through 4 and 7 through 10. All optical connectors are located on the front panel and the connectors are angled and recessed.

Each carrier motherboard can hold up to two VOA modules. There are four types of VOA modules available:

•Single WB-VOA modules

•Dual WB-VOA modules

•Single band PB-OE modules

•Dual band PB-OE modules

Single WB-VOA Modules

The single WB-VOA modules accept one signal and attenuate all frequencies within that signal. The signal can contain a single channel, such as the OSC, a band of channels, or multiple channel bands.

Single WB-VOA modules have two types of interfaces:

•Voain interfaces

•Voaout interfaces

Figure 10-2 shows the interfaces for the single WB-VOA module.

Figure 10-2 Single WB-VOA Module Interfaces

Dual WB-VOA Modules

The dual WB-VOA modules consist of two WB-VOA units that each accepts one signal and attenuates all frequencies within that signal.

Dual WB-VOA modules have two types of interfaces:

•Voain interfaces

•Voaout interfaces

Figure 10-3 shows the interfaces for the dual WB-VOA module.

Figure 10-3 Dual WB-VOA Module Interfaces

Single Band PB-OE Modules

A single band PB-OE module accepts an incoming signal containing at least two bands, which are split by an optical filter into two components. The first component is attenuated and the second component is passed to another module where it can be attenuated and passed back to the original PB-OE. The PB-OE then recombines the two equalized components into a single signal and sends it out.

Single PB-OE modules have four types of interfaces:

•Voafilterin interfaces and subinterfaces

•Voafilterout interfaces

•Voabypassin interfaces

•Voabypassout interfaces

Figure 10-4 shows the interfaces for the single PB-OE module.

Figure 10-4 Single PB-OE Module Interfaces

Dual Band PB-OE

If two consecutive bands have to be attenuated, use a dual band PB-OE module. When more than two add bands are to be attenuated, multiple VOA modules can be cascaded. The dual band PB-OE supports bands AB, CD, EF, and GH. Use a dual band PB-OE module to equalize signals with at least two bands.

Dual PB-OE modules have four types of interfaces:

•Voafilterin interfaces and subinterfaces

•Voafilterout interfaces

•Voabypassin interfaces

•Voabypassout interfaces

Figure 10-5 shows the interfaces for the dual PB-OE module.

Figure 10-5 Dual PB-OE Module Interfaces

Configuring VOA Module Interfaces

To configure optical amplification support on the Cisco ONS 15530, perform the following steps:

Step 1 Configure attenuation values.

Step 2 Configure alarm thresholds (optional).

Step 3 Configure topology neighbor information (optional).

For information on configuring topology neighbor information, see the "Configuring Interfaces in the Network Topology" section on page 14-24.

Configuring Attenuation

The Cisco ONS 15530 supports two types of attenuation, automatic and manual. The WB-VOA module allows both automatic and manual attenuation. The PB-OE module only allows manual attenuation.

For more information on configuring attenuation in an amplified network, refer to the
Cisco ONS 15530 Optical Turn-Up and Test Guide publication.

Configuring Automatic Attenuation

The WB-VOA modules support automatic attenuation. Once you set a desired signal power, the system checks every second until the signal power comes into attenuable range. Then the system sets the attenuation so that the signal transmits at the desired power value. The system waits 60 seconds before checking the signal power again and adjusting the attenuation if necessary. The system automatically adjusts the attenuation only if it is at least 0.5 dBm out of range.

To configure automatic attenuation on a WB-VOA module interface, perform the following steps:

Command

Purpose

Step 1

Switch# configure terminal

Switch(config)#

Enters global configuration mode.

Step 2

Switch(config)# interface voain slot/subcard/port

Switch(config-if)#

Selects the WB-VOA module interface to configure and enters interface configuration mode.

Step 3

Switch(config-if)# optical attenuation automatic desired-power value

Specifies the automatic attenuation value in units of 0.1 dBm.

Note Automatic attenuation and manual attenuation are mutually exclusive. Only one method can be active at a given time. If manual attenuation is in effect, the optical attenuation automatic desired-power command overrides that configuration.

Example

The following example shows how to configure automatic attenuation on a voain interface on a WB-VOA module:

Switch# configure terminal
Switch(config)# interface voain 1/0/0
Switch(config-if)# optical attenuation automatic desired-power 150
Configuring Manual Attenuation

The WB-VOA modules and PB-OE modules support manual configuration of attenuation. When you manually configure the attenuation, the interface attenuates at the value specified in the command.

To configure manually attenuation on a VOA module interface, perform the following steps:

Command

Purpose

Step 1

Switch# show interfaces {voafilterin slot/subcard/port.subinterface | voain slot/subcard/port} attenuation desired-power value

Shows the attenuation value necessary to achieve the desired power value.

Step 2

Switch# configure terminal

Switch(config)#

Enters global configuration mode.

Step 3

Switch(config)# interface {voafilterin slot/subcard/port.subinterface | voain slot/subcard/port}

Switch(config-if)#

Selects the VOA module interface to configure and enters interface configuration mode.

Step 4

Switch(config-if)# optical attenuation manual value

Specifies the manual attenuation value in units of 0.1 dBm.

Note Automatic attenuation and manual attenuation are mutually exclusive. Only one method can be active at a given time. If automatic attenuation is in effect, the optical attenuation manual command overrides that configuration.

Example

The following example shows how to manually configure attenuation on a voafilterin subinterface on a PB-OE module:

Switch# configure terminal
Switch(config)# interface voafilterin 1/0/0.1
Switch(config-subif)# optical attenuation manual 20

The following example shows how to calculate and configure attenuation on a voain interface on a WB-VOA module:

Switch# show interfaces voain 1/0/0 attenuation desired-power 0
Current Output Power: 10.0dBm
Desired Output Power: 0.0dBm
Minimum settable Attenuation: 3.4dB
Maximum settable Attenuation: 30.0dB
Current set Attenuation: 3.4dB (default)
Attenuation needed to achieve Desired Output Power:13.4dB
Switch# configure terminal
Switch(config)# interface voain 1/0/0
Switch(config-if)# optical attenuation manual 13.4

Displaying the Attenuation Configuration

To display the attenuation configuration, use the following EXEC command:

Command

Purpose

show interfaces {voafilterin slot/subcard/port.subinterface | voain slot/subcard/port}

Displays the VOA module interface configuration.

Example

The following example shows how to display the attenuation configuration of a voafilterin subinterface:

Switch# show interfaces voafilterin 9/0/0.1
voaFilterIn9/0/0.1 is up, line protocol is up
Hardware is voaFilterIn Port
Port Transmit (Tx) Support: False
Port Receive (Rx) Support: True
VOA This Port operates on: 2
Attenuation Mode: manual
Minimum settable Attenuation: 3.7dB
Maximum settable Attenuation: 30.0dB
   Current set Attenuation: 3.7dB (default)
Light Quality: Good/In Range
Current Output Power: -0.5dBm
Low Alarm Threshold Severity: major (default)
Low Warning Threshold: -27.0dBm (default)
Low Warning Threshold Severity: not alarmed (default)
High Warning Threshold: 9.0dBm (default)
High Warning Threshold Severity: not alarmed (default)
High Alarm Threshold: 11.0dBm (default)
High Alarm Threshold Severity: major (default)

The following example shows how to display the attenuation configuration of a voain interface:

Switch# show interfaces voain 9/0/0
voaIn9/0/0 is up, line protocol is up
Hardware is voaIn Port
Port Transmit (Tx) Support: False
Port Receive (Rx) Support: True
VOA This Port operates on: 1
Attenuation Mode: manual
   Minimum settable Attenuation: 1.7dB
Maximum settable Attenuation: 30.0dB
   Current set Attenuation: 15.0dB
Light Quality: Good/In Range
Current Output Power: -12.1dBm
Low Alarm Threshold Severity: major (default)
Low Warning Threshold: -27.0dBm (default)
Low Warning Threshold Severity: not alarmed (default)
High Warning Threshold: 9.0dBm (default)
High Warning Threshold Severity: not alarmed (default)
High Alarm Threshold: 11.0dBm (default)
High Alarm Threshold Severity: major (default)

About Optical Thresholds

You can configure optical thresholds on the VOA module interfaces that issue alarm messages to the system if the optical thresholds are exceeded. Every second the monitoring facility updates the counters that correspond to the alarm thresholds. When the signal degrades, or fails entirely, the system issues alarms to the console. These alarms can help isolate failures in the system and in the network.

Configuring Optical Receive Power Thresholds

The VOA modules have optical receive power thresholds monitored by the Cisco ONS 15530. This section describes four types of alarm threshold configuration procedures:

•Low Power Alarm

•Low Power Warning

•High Power Warning

•High Power Alarm

Low power warnings are raised when the received optical power drifts too close to LOL (Loss of Light). Low power alarms show a critical condition of LOL. High power warnings are raised when the received optical power drifts too close to high power alarm conditions. High power alarm are raised when received optical power exceeds the receiver saturation threshold.

To configure power thresholds on VOA module interfaces, perform the following steps, beginning in global configuration mode:

Command

Purpose

Step 1

Switch(config)# interface {voafilterin slot/subcard/port.subinterface | voain slot/subcard/port}

Selects the VOA module interface to configure and enters interface configuration mode.

Step 2

Switch(config-if)# optical threshold power receive after-attenuation {low | high} {alarm | warning} value [severity {critical | major | minor | not alarmed | not reported}]

Specifies the threshold value in units of 0.1 dBm. The default values are as follows:

Low alarm: -29 dBm

Low warning: -27 dBm

High warning: 9 dBm

High alarm: 11 dBm

Alarm severity: major

Warning severity: not alarmed

Example

The following example shows how to manually configure an optical threshold on a voafilterin subinterface on a PB-OE module:

Switch# configure terminal
Switch(config)# interface voafilterin 1/0/0.1
Switch(config-subif)# optical threshold power receive after-attenuation low alarm -210

The following example shows how to configure an optical threshold on a voain interface on a WB-VOA module:

Switch# configure terminal
Switch(config)# interface voain 1/0/0
Switch(config-if)# optical threshold power receive after-attenuation high alarm -200
Displaying the Optical Threshold Configuration

To display the configuration of an optical threshold for a VOA module interface, use the following EXEC command:

Command

Purpose

show interfaces {voafilterin slot/subcard/port.subinterface | voain slot/subcard/port}

Displays the VOA module interface configuration.

Example

The following example shows how to display the threshold configuration of a voafilterin subinterface:

Switch# show interfaces voafilterin 2/1/0.2
voaFilterIn2/1/0.2 is up, line protocol is up
Hardware is voaFilterIn Port
Port Transmit (Tx) Support: False
Port Receive (Rx) Support: True
VOA This Port operates on: 1
  Attenuation Mode: manual
  Minimum settable Attenuation: 3.7dB
Maximum settable Attenuation: 30.0dB
Current set Attenuation: 20.0dB
Light Quality: Low Warning Threshold Exceeded
Current Output Power: -16.3dBm
Low Alarm Threshold: -20.0dBm
Low Alarm Threshold Severity: major (Default Value)
Low Warning Threshold: -15.0dBm
Low Warning Threshold Severity: not-alarm (Default Value)
High Warning Threshold: -10.0dBm
High Warning Threshold Severity: not-alarm (Default Value)
High Alarm Threshold: -5.0dBm
High Alarm Threshold Severity: major (Default Value)

The following example shows how to display the threshold configuration of a voain interface:

Switch# show interfaces voain 7/1/0
voaIn7/1/0 is up, line protocol is down
Hardware is voaIn Port
Port Transmit (Tx) Support: False
Port Receive (Rx) Support: True
VOA This Port operates on: 1
  Attenuation Mode: manual
  Minimum settable Attenuation: 1.7dB
Maximum settable Attenuation: 30.0dB
Current set Attenuation: 1.7dB
Light Quality: Loss of Light/Low Alarm Threshold Exceeded
Current Output Power: -256.0dBm
Low Alarm Threshold: -29.0dBm (Default Value)
Low Alarm Threshold Severity: major (Default Value)
Low Warning Threshold: -20.0dBm
Low Warning Threshold Severity: not-alarm (Default Value)
High Warning Threshold: -5.0dBm
High Warning Threshold Severity: not-alarm (Default Value)
High Alarm Threshold: 0.0dBm
High Alarm Threshold Severity: major (Default Value)

	Command	Purpose
Step 1	Switch# configure terminal Switch(config)#	Enters global configuration mode.
Step 2	Switch(config)# interface voain slot/subcard/port Switch(config-if)#	Selects the WB-VOA module interface to configure and enters interface configuration mode.
Step 3	Switch(config-if)# optical attenuation automatic desired-power value	Specifies the automatic attenuation value in units of 0.1 dBm.

	Command	Purpose
Step 1	Switch# show interfaces {voafilterin slot/subcard/port.subinterface \| voain slot/subcard/port} attenuation desired-power value	Shows the attenuation value necessary to achieve the desired power value.
Step 2	Switch# configure terminal Switch(config)#	Enters global configuration mode.
Step 3	Switch(config)# interface {voafilterin slot/subcard/port.subinterface \| voain slot/subcard/port} Switch(config-if)#	Selects the VOA module interface to configure and enters interface configuration mode.
Step 4	Switch(config-if)# optical attenuation manual value	Specifies the manual attenuation value in units of 0.1 dBm.