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ROADM Solutions

 

The BTI7800 Series ROADM family of modules provides reconfigurable optical add/drop multiplexing, reach extension, and end-to-end service management for the BTI7800 optical network.

Note

The ROADM family of modules is supported starting with release 2.1.1.

The ROADM family consists of ROADM modules that provide wavelength routing, EDFA line amplifier modules that provide automatic span loss compensation and reach extension, CFP2-format EDFA pluggable pre-amplifier modules that provide supplementary amplification for the host module, and passive multiplexer/demultiplexer modules that provide wavelength access.

The common control system embedded in ROADM and line amplifier modules supports automated network and channel equalization, simplifying the ongoing optimization and power management of the optical network. The ROADM solution also provides end-to-end channel performance metrics that allow comprehensive service visibility and facilitate troubleshooting.

Communication between ROADM elements is performed through an integrated optical service channel (OSC). Through the OSC, ROADM elements share information and automatically measure system parameters and adjust system control targets to manage channel power levels. The OSC enables turning up of the optical layer without using any service wavelengths, and provides accurate span measurement, and robust optical shutdown capabilities.

Note

The BTI7800 Series ROADM family of modules does not interoperate with the BTI7000 Series Dynamic Optical Layer.

Note

The BTI7800 Series ROADM solution does not provide dispersion compensation. You must use coherent transceivers when connecting to BTI7800 Series ROADM equipment.

ROADM Terminology

A ROADM module is a BTI7800 module that provides wavelength routing and channel equalization. An example of a ROADM module is the 2-Port Reconfigurable Optical Add/Drop Multiplexer (ROADM2).

A ROADM element is a BTI7800 module that provides a designated function as a constitutent part of a ROADM node. A ROADM module is a ROADM element, but a ROADM element is not necessarily a ROADM module. Examples of ROADM elements are the 2-Port Reconfigurable Optical Add/Drop Multiplexer (ROADM2) and the 96-Channel Fixed Mux/Demux (FMD96).

A ROADM node is a configuration of ROADM elements that together provide a nodal function in an optical network. The ROADM node is a concept only, and exists purely to convey the type of function that the constituent ROADM elements provide. An example of a ROADM node is the add/drop node.

ROADM Nodes

The BTI7800 ROADM family of modules can be configured in different ways to provide different nodal functions for the optical network. Figure 1 shows examples of possible ROADM nodes in an optical network:

Figure 1: Example ROADM Nodes
Example ROADM Nodes
Note

The ROADM node is implicitly defined by how its constituent modules are configured. It is not an explicitly configurable entity, attribute, or parameter.

  • Equalizing terminal node: An equalizing terminal node consists of a ROADM module that adds and drops wavelengths at the end of a linear network. This configuration is intended for multi-wavelength connectivity between two sites. A multiplexer/demultiplexer co-deployed with the ROADM module provides access to the add/drop wavelengths.

  • Add/Drop node: A ROADM node is used to connect sites together in a linear, ring or mesh configuration. Each node consists of two or more ROADM modules that provide optical add/drop/pass-through capability. A multiplexer/demultiplexer co-deployed with each ROADM module provides access to the add/drop wavelengths for that module.

    Two-degree add/drop node, for example, terminates two network spans and provides add/drop/pass-through of wavelengths.

  • Line equalizing node: A line-equalizing node corrects channel power imbalances at a transit site. Each node consists of two back-to-back ROADM modules that actively balance channel powers to remove channel power disparity.

  • Line amplifier node: A line amplifier node amplifies the composite signal at a transit site. It is generally deployed between equalizing nodes to provide composite signal amplification. Each node consists of two back-to-back ILA modules where each module provides amplification for an incoming span.

Note

The above list does not cover all possibilities. Other types of ROADM nodes can be created.

Note

Limits exist on the number of ROADM and ILA modules you can install in a BTI7800 system. See the BTI7800 Series Hardware Overview and Installation Guide for more information.

Equalizing Terminal Node

The equalizing terminal node is used at the terminal ends of a linear network of one or more spans. The equalizing terminal node provides add/drop access to all wavelengths on the network span, performs bidirectional amplification, and applies channel equalization and tilt compensation to all outbound channels.

Figure 2: Equalizing Terminal Node with a ROADM2 Module
Equalizing Terminal Node with a ROADM2 Module

An equalizing terminal node consists of the following equipment and configuration:

  • One ROADM module connected to the network span.

  • One multiplexer/demultiplexer module connected to one of the client ports of the ROADM module. The multiplexer/demultiplexer module provides access to the add/drop wavelengths for the connected ROADM module. The other client port is unused.

  • An optional PRE module to provide supplementary amplification of the incoming line signal. The PRE module is installed in the PRE slot of the ROADM module. The ROADM module directs the incoming composite line signal to the PRE module prior to regular amplification and routing.

Add/Drop Node

An add/drop node consists of two or more ROADM modules deployed together to provide wavelength pass-through between network spans and wavelength add/drop for local access. Each ROADM module is connected to a single network span (degree). The number of ROADM modules required is equal to the number of network spans connected to the node. A node with two network spans requires two ROADM modules. A node with eight network spans requires eight ROADM modules.

Each ROADM module performs bidirectional amplification and applies channel equalization and tilt compensation to all outbound channels.

Local access to add/drop wavelengths is provided through multiplexer/demultiplexer modules. Each multiplexer/demultiplexer attaches to a single ROADM module to provide local access to the add/drop wavelengths of the network span connected to that ROADM module. The multiplexer/demultiplexer cannot provide access to add/drop wavelengths for a ROADM module to which it is not directly attached. The minimum number of multiplexer/demultiplexer modules required is equal to the number of network spans with add/drop wavelengths for this node.

The following figure shows an add/drop node with two ROADM modules.

Figure 3: Add/Drop Node
Add/Drop Node

Each ROADM module performs the following switching functions within an add/drop node:

  • Routes wavelengths from its attached span to directly connected ROADM modules for transmission into another span.

  • Routes wavelengths from its attached span to the locally attached multiplexer/demultiplexer module. The wavelengths are passed in a composite signal to the multiplexer/demultiplexer for demultiplexing.

  • Multiplexes pass-through wavelengths (from other ROADM modules) with the 'add' wavelengths (from the locally attached multiplexer/demultiplexer) for transmission into the attached span.

Note the following:

  • Each ROADM module can only pass through wavelengths between the attached span and ROADM modules that are directly connected. Not all ROADM modules need to be connected with each other. Only those ROADM modules with pass-through traffic between the respective spans need to be connected together.

  • Each ROADM module can only add and drop wavelengths between the attached span and the directly connected multiplexer/demultiplexer. The ROADM module cannot add or drop wavelengths from other ROADM modules and the directly connected multiplexer/demultiplexer.

  • Typically, the ROADM module adds and drops wavelengths through a multiplexer/demultiplexer to a UFM residing on the same chassis. It is also possible to configure the ROADM module to add and drop wavelengths through a multiplexer/demultiplexer to a UFM residing on another system, or to other vendors' equipment. See Alien Wavelengths.

  • If a wavelength is configured for pass-through, the same wavelength cannot be configured for add/drop on either of the ROADM modules.

  • Wavelengths on different spans are independent of each other. The same wavelength can be reused (Figure 4).

    Figure 4: Reusing Channels
    Reusing Channels

Two-Degree Add/Drop Node

A 2-degree add/drop node terminates two network spans and provides add/drop/pass-through of wavelengths. It provides bidirectional amplification, tilt compensation, and channel equalization of the DWDM signals.

Figure 5: Two-Degree Add/Drop Node with ROADM2 Modules
Two-Degree Add/Drop Node with ROADM2 Modules
Note

There are no fixed roles for the client ports. All client ports (C1 to Cn) have equivalent capability. The client port connections shown in this section are examples only, and can be changed.

A 2-degree add/drop node consists of the following equipment and configuration:

  • Two ROADM modules. Each module's L1 port connects to a network span. Client ports of the two modules (for example, C2) are connected with each other for routing pass-through traffic between spans.

  • One or more multiplexer/demultiplexer modules. One multiplexer/demultiplexer module is required for each network span that carries add/drop wavelengths. If a network span does not have add/drop wavelengths, then it does not require a multiplexer/demultiplexer. The multiplexer/demultiplexer's L1 port connects to a client port (for example, C1) of its mating ROADM module. The multiplexer/demultiplexer's client ports connect to local layer 1 transport equipment such as transponders.

    In the 'drop' direction, the multiplexer/demultiplexer takes the incoming composite DWDM signal from its L1 port and demultiplexes it into individual wavelengths on its client ports. Each client port carries a specific fixed wavelength. In the 'add' direction, the multiplexer/demultiplexer multiplexes the individual client signals into a composite DWDM signal for the ROADM module to process.

  • Optional PRE modules to provide supplementary amplification of the incoming line signals. The PRE module is installed in the PRE slot of the ROADM module. The ROADM module directs the incoming composite line signal to the PRE module (if enabled) prior to regular amplification and routing.

In a given direction, a pass-through wavelength is amplified by the receiving ROADM module, routed through the connected client ports (for example, C2) to the transmitting ROADM module where the wavelength is equalized with the other co-travelling wavelengths, amplified, and launched into the next span.

Add/drop wavelengths are routed within a single ROADM module between the network span attached to the L1 port and the multiplexer/demultiplexer connected to a client port (for example, C1). Wavelengths cannot be added or dropped from a network span attached to one ROADM module to a multiplexer/demultiplexer connected to the other ROADM module. A multiplexer/demultiplexer is only required if there are add/drop wavelengths for that span.

The signal path followed by an add/drop wavelength is as follows:

  • In the 'drop' direction, the received signal is amplified, and then passed out the client port (for example, C1) to the multiplexer/demultiplexer where the selected wavelengths are routed to the attached equipment.

  • In the 'add' direction, the multiplexer/demultiplexer multiplexes the client signals from the attached equipment and passes the composite signal to the client port (for example, C1) of the attached ROADM module. The ROADM module selects and further multiplexes the 'add' channels with the pass-through channels, amplifies, equalizes, and launches the final composite signal onto the line.

Line-Equalizing Node

The line-equalizing node amplifies the incoming DWDM signal and equalizes the individual wavelengths before transmitting out the other span. It is deployed where future add/drop capability might be required, or to support extended reach systems by eliminating channel power disparity. All channels are passed through from one span to the opposite span. No multiplexer/demultiplexer modules are required.

Figure 6: Line-Equalizing Node with ROADM2 Modules
Line-Equalizing Node with ROADM2 Modules
Note

There are no fixed roles for the client ports. All client ports (C1 to Cn) have equivalent capability. The client port connections shown in this section are examples only, and can be changed.

A line-equalizing node consists of the following equipment and configuration:

  • Two ROADM modules where each module's L1 port connects to a network span. The C2 ports of the two modules are connected with each other for routing all traffic between spans. The C1 ports are not used.

  • Optional PRE modules to provide supplementary amplification of the incoming line signals. The PRE module is installed in the PRE slot of the ROADM module. The ROADM module directs the incoming composite line signal to the PRE module (if enabled) prior to regular amplification and routing.

Pass-through wavelengths are routed from the L1 port of one ROADM module through the interconnected C2 ports and out the L1 port of the other ROADM module. The first ROADM module amplifies the incoming composite signal to compensate for any losses on the line and can pass the composite signal through the attached PRE module to achieve greater amplification.

Note

The routing description in this section is a generalization. Exact details differ between the different types of ROADM modules.

Once the composite signal is amplified, it is passed out the C2 port to the other ROADM module, where the channels of the composite signal are equalized and launched onto the line.

Line Amplifier Node

A line amplifier node provides amplification and tilt compensation of the composite DWDM signals but does not equalize the individual wavelengths. All channels are passed through from one span to the other span. No ROADM or multiplexer/demultiplexer modules are required.

Figure 7: Line Amplifier Node with ILA Modules
Line Amplifier Node with ILA Modules

A line amplifier node consists of the following equipment and configuration:

  • Two ILA modules, with each module connecting to a network span. The C1 ports of the two modules are connected with each other for passing traffic between spans.

  • Optional PRE modules to provide supplementary amplification of the incoming line signals. The PRE module is installed in the PRE slot of the ILA module. The ILA module directs the incoming composite line signal to the PRE module (if enabled) prior to regular amplification and routing.

The input signal on the L1 port of the ILA module is amplified (possibly through a PRE) to compensate for incoming line losses and passed out the C1 port to the second ILA, where it is sent out the other span. Amplification is applied to the composite DWDM C-band signal only.

Split ROADM Node

A split ROADM node is a highly survivable configuration where ROADM modules comprising a ROADM node are located in separate network elements managed by separate CMMs. A failure or outage at one network element affects traffic on that network element only. Add/drop traffic on the same ROADM node but on another network element is not affected if the traffic is not configured to pass through the failed network element.

Like a regular ROADM node, a split ROADM node is conceptual, and cannot be explicitly created or deleted. A ROADM node becomes a split ROADM node once client port fiber connections are created between ROADM modules residing on different network elements.

Configuring ROADM functionality on a split ROADM node differs from configuring ROADM functionality on a regular ROADM node in the following ways:

Alien Wavelengths

In some situations, it might be desirable to add/drop a wavelength from a ROADM node to equipment on another network element or device. This wavelength is called an alien wavelength since the local add/drop endpoint is unknown to the local ROADM node. The local ROADM node routes the alien wavelength(s) between the line span and the attached multiplexer/demultiplexer, but does not validate the external endpoint connected to the other side of the multiplexer/demultiplexer (Figure 8).

Figure 8: Add/Drop Alien Wavelength
Add/Drop Alien Wavelength

The external endpoint can be located on other vendors' equipment, or it can simply be a BTI7800 module that resides on another network element.

ROADM Component Model

The ROADM software component model consists of a number of objects as described in the following table:

Component Name

Description

Instance Range

dol (Dynamic Optical Layer).

This is the ROADM container component. It is automatically created when a ROADM element is added to a system.

There is one unnumbered instance per system.

port

Ports of the proper type are automatically created under dol when a ROADM, ILA, PRE, or multiplexer/demultiplexer module is added.

ROADM/ILA: There is one line port, one PRE port, and one or more client ports (depending on the module).

PRE: There is one port on the PRE module itself.

multiplexer/demultiplexer: There is one line port and multiple client ports (one per channel).

oms

The optical multiplex sections (OMS) are automatically created under dol when a ROADM or ILA module is added. The OMS represents the multiplexed signal (C-band).

ROADM/ILA: There is a single OMS per client or line port.

osc

The optical service channels (OSC) are automatically created under dol when a ROADM or ILA module is added. The OSC is responsible for managing and monitoring communications with other nodes as well as within a node.

ROADM/ILA: There is a single OSC per client or line port.

och

The optical channel (OCH) is a user-traffic-bearing bidirectional channel that is defined by its central frequency (wavelength) and bandwidth. It is cross-connected within the node as part of an overall optical service.

The operator creates the line port och components under dol when provisioning an optical service.

The system automatically creates the client port och components under dol when optical channel cross-connects are added.

ROADM/ILA: There can be multiple OCHs per client or line port, up to the number of wavelengths supported.

och-xcon

The optical channel cross-connect specifies how a particular wavelength is routed within the ROADM node.

The operator creates the och-xcon component under dol when provisioning an optical service.

The och-xcon consists of a pairing of endpoints, as follows:

  • pass-through: between an och on a line port and an och on a line port of another ROADM module

  • pass-through (split ROADM): between an och on a line port and an och on a client port of the same ROADM module

  • add/drop: between an och on a line port and a UFM interface

There can be multiple OCH-XCONs in the system.

fiber-conn

The fiber connection represents the physical fiber connectivity between ports on the local ROADM node (intra-nodal), and between ports across different ROADM nodes (inter-nodal). It allows the system to check the actual physical connectivity against the provisioned connectivity. All fiber connections are bidirectional.

Fiber connections are mandatory.

See Provisioning fiber connections.

There are multiple fiber connections in the system (one configured fiber connection for each physical fiber pair).

Provisioning Fiber Connections

Fiber connections represent the physical fiber connectivity between ports on the local ROADM node (intra-nodal), and between ports across different ROADM nodes (inter-nodal). It allows the system to check the actual physical connectivity against the provisioned connectivity. All fiber connections are bidirectional.

Fiber connections are mandatory.

Note

If a fiber connection is not provisioned on a port, none of the components associated with that port will raise alarms or conditions.

If auto-provisioning is enabled (Auto-Provisioning of BTI7800 Equipment), then some of the fiber connections might be automatically created when the corresponding physical fibers are installed.

For details, see the following:

Provisioning Intra-Nodal Fiber Connections

Use this procedure to provision intra-nodal fiber connections. Fiber connections are mandatory.

Note

If a fiber connection is not provisioned on a port, none of the components associated with that port will raise alarms or conditions.

If auto-provisioning is enabled and you do not want to pre-provision, then you might be able to skip this procedure. When auto-provisioning is enabled, the system automatically provisions the following intra-nodal fiber connections when the corresponding physical fibers are connected and the modules, associated ports, and the OSC are enabled:

  • intra-nodal fiber connections between ROADM client ports (for regular and split ROADM nodes)

  • intra-nodal fiber connections between ILA client ports

All other intra-nodal fiber connections must be manually created.

  1. Confirm that you need to manually provision fiber connections.

    In general, you do not need to manually configure fiber connections if auto-provisioning is enabled.

  2. Enter configuration mode.
  3. Configure the fiber connection between two ROADM elements.

    Provisioning fiber-conn allows the BTI7800 to detect discrepancies between the configured fiber connection and the actual fiber connection. A fiber-conn is mandatory.

    Note

    This command assumes the modules are connected by their C1 ports. This is an example only. There is no restriction on which client ports are used for interconnecting the ROADM modules, nor does the same client port need to be used on both modules.

    For example, to create a fiber-conn between the C1 ports of two ROADM modules:

    bti7800(config)# dol fiber-conn port:1/6/0/C1 port:1/11/0/C1

    When configuring a fiber connection between ROADM modules on a split ROADM node, append the IP address of the NE at the other end of the fiber to the port identifier. The IP address to use is the shared management IP address of the network element. For example, if the other ROADM module is on an NE with shared management IP address 10.1.100.2:

    bti7800(config)# dol fiber-conn port:1/6/0/C1 port:1/11/0/C1@10.1.100.2
    Note

    For a split ROADM node, you must configure two fiber connections, one for each NE at each end of the fiber.

  4. If desired, enable far end identifier monitoring.

    For example:

    bti7800(config-fiber-conn-port:1/6/0/C1/port:1/11/0/C1)# fe-im-mon true

    When far end identifier monitoring is enabled, the provisioned fiber connection is compared against the actual fiber connection. If there is a mismatch, the system raises the Far End Identification Mismatch (feim) alarm.

    Note

    If the fiber connection is auto-provisioned, the feim alarm will not be raised because there will not be a mismatch.

  5. Apply the provisioning.
    bti7800(config-fiber-conn-port:1/6/0/C1/port:1/11/0/C1)# commit

Provisioning Inter-Nodal Fiber Connections

Use this procedure to provision inter-nodal fiber connections. Fiber connections are mandatory.

Note

If a fiber connection is not provisioned on a port, none of the components associated with that port will raise alarms or conditions.

If auto-provisioning is enabled and you do not want to pre-provision, then you can skip this procedure because the system automatically provisions the inter-nodal fiber connections when the corresponding physical fibers are connected and the modules, associated ports, and the OSC are enabled.

  1. Confirm that you need to manually provision fiber connections.

    In general, you do not need to manually configure fiber connections if auto-provisioning is enabled.

  2. Enter configuration mode.
  3. Configure the fiber connection with the far end ROADM node.

    Provisioning fiber-conn allows the BTI7800 to detect discrepancies between the configured fiber connection and the actual fiber connection. A fiber-conn is mandatory.

    For example, to create a fiber-conn between the line port of the local ROADM module and the far end line port on the NE identified by IP address 10.1.1.1:

    bti7800(config)# dol fiber-conn port:1/9/0/L1 port:1/8/0/L1@10.1.1.1
  4. Specify the fiber type.

    For example:

    bti7800(config-fiber-conn-port:1/9/0/L1/port:1/8/0/L1@10.1.1.1)# fiber-type ndsf
  5. If desired, enable far end identifier monitoring.

    For example:

    bti7800(config-fiber-conn-port:1/9/0/L1/port:1/8/0/L1@10.1.1.1)# fe-im-mon true

    When far end identifier monitoring is enabled, the provisioned fiber connection is compared against the actual fiber connection. If there is a mismatch, the system raises the Far End Identification Mismatch (feim) alarm.

    Note

    If the fiber connection is auto-provisioned, the feim alarm will not be raised because there will not be a mismatch.

  6. Apply the provisioning.
    bti7800(config-fiber-conn-port:1/9/0/L1/port:1/8/0/L1@10.1.1.1)# commit

Provisioning a Pass-Through Connection

Use this procedure to provision a bidirectional pass-through connection from one line span to another line span on a ROADM node.

Prerequisites:

  • A pair of ROADM modules must be provisioned, one for each line span.

  • All relevant ports must be created. The ROADM module ports are auto-created when the ROADM module is added.

  • The inter-nodal (line-side) fiber connections must be created. See Provisioning inter-nodal fiber connections.

Figure 9: Pass-Through Connection Example
Pass-Through Connection Example
Note

If you are configuring a pass-through connection on a split ROADM node, see Provisioning a passthrough connection on a split ROADM node.

  1. Enter configuration mode.
  2. Create the optical channel on the line port of the first ROADM module.

    For example, to create an optical channel on the line port of a ROADM module in chassis 1, slot 6, with a frequency of 192.85 THz and a name of chan285:

    bti7800(config)# dol och:1/6/0/L1/chan285 central-frequency 192.85

    The name is a character string that should be sufficiently meaningful to allow you to identify the channel. In this example, the last three digits of the frequency are used as part of the identifier.

  3. Create the optical channel on the line port of the second ROADM module.

    For example, to create an optical channel on the line port of a ROADM module in chassis 1, slot 11, with a frequency of 192.85 THz and a name of chan285:

    bti7800(config)# dol och:1/11/0/L1/chan285 central-frequency 192.85
  4. Configure the fiber connection between the two ROADM modules if a fiber connection does not already exist.

    Provisioning fiber-conn allows the BTI7800 to detect discrepancies between the configured fiber connection and the actual fiber connection. A fiber-conn is mandatory. For more information on provisioning intra-nodal fiber connections, see Provisioning intra-nodal fiber connections.

    For example, to create a fiber-conn between the C1 ports of the two ROADM modules:

    bti7800(config)# dol fiber-conn port:1/6/0/C1 port:1/11/0/C1
    Note

    This command assumes the ROADM modules are connected by their C1 ports as in the above diagram. This is an example only. There is no restriction on which client ports are used for interconnecting the ROADM modules, nor does the same client port need to be used on both modules.

  5. Create the cross-connect.

    For example:

    bti7800(config)# dol och-xcon och:1/6/0/L1/chan285 och:1/11/0/L1/chan285
  6. Commit the provisioning.
    bti7800(config)# commit
    Note

    The system automatically creates the optical channel (with the same channel name) on the ROADM client port (och:1/6/0/C1/chan285).

Provisioning a Pass-Through Connection on a Split ROADM Node

Use this procedure to provision a bidirectional pass-through connection from one line span to another line span on a split ROADM node.

Prerequisites:

  • A pair of ROADM modules must be provisioned, one for each NE (and line span).

  • All relevant ports must be created. The ROADM module ports are auto-created when the ROADM module is added.

  • The inter-nodal (line-side) fiber connections must be created. See Provisioning inter-nodal fiber connections.

Figure 10: Pass-Through Connection Example (Split ROADM Node)
Pass-Through Connection Example (Split ROADM Node)
  1. Enter configuration mode on NE A.
  2. Configure the fiber connection between the two ROADM modules if a fiber connection does not already exist.

    Provisioning fiber-conn allows the BTI7800 to detect discrepancies between the configured fiber connection and the actual fiber connection. A fiber-conn is mandatory. For more information on provisioning intra-nodal fiber connections, see Provisioning intra-nodal fiber connections.

    For example, to create the fiber-conn on NE A:

    bti7800(config)# dol fiber-conn port:1/6/0/C1 port:1/11/0/C1@10.1.100.2
    Note

    This command assumes the ROADM modules are connected by their C1 ports as in the above diagram. This is an example only. There is no restriction on which client ports are used for interconnecting the ROADM modules, nor does the same client port need to be used on both modules.

  3. Create an optical channel on the line port of the ROADM module on NE A.

    For example, to create an optical channel on the line port of a ROADM module in chassis 1, slot 6, with a frequency of 192.85 THz and a name of chan285:

    bti7800(config)# dol och:1/6/0/L1/chan285 central-frequency 192.85

    The name is a character string that should be sufficiently meaningful to allow you to identify the channel. In this example, the last three digits of the frequency are used as part of the identifier.

  4. Create the cross-connect on NE A and apply the changes.

    For example:

    bti7800(config)# dol och-xcon och:1/6/0/L1/chan285 och:1/6/0/C1/chan285
    Note

    The client port optical channel specified in the command is automatically created after executing this command. You do not need to create the client port optical channel explicitly.

  5. Repeat 1 to 4 on NE B.

    For example:

    bti7800# config Entering configuration mode terminal

Provisioning an Add/Drop Connection

Use this procedure to provision a bidirectional add/drop connection from a line span on a ROADM module to a UFM interface through a multiplexer/demultiplexer.

Prerequisites:

  • The ROADM module, multiplexer/demultiplexer, and UFM must be provisioned.

  • All relevant ports must be created. The ROADM module ports and the multiplexer/demultiplexer ports are auto-created when the respective modules are added. The UFM interface must be created manually.

  • The inter-nodal (line-side) fiber connections must be created. See Provisioning inter-nodal fiber connections.

Figure 11: Add/Drop Connection Example with a Multiplexer/Demultiplexer
Add/Drop Connection Example with a Multiplexer/Demultiplexer
  1. Enter configuration mode.
  2. Create the optical channel on the line port of the ROADM module.

    For example, to create an optical channel on the line port of a ROADM module in chassis 1, slot 6, with a frequency of 192.95THz and a name of chan295:

    bti7800(config)# dol och:1/6/0/L1/chan295 central-frequency 192.95 bti7800(config-dol-och:1/6/0/L1/chan295)# top

    The name is a character string that should be sufficiently meaningful to allow you to identify the channel. In this example, the last three digits of the frequency are used as part of the identifier.

  3. Configure the fiber connection between the ROADM module and the multiplexer/demultiplexer if a fiber connection does not already exist.

    Provisioning fiber-conn allows the BTI7800 to detect discrepancies between the configured fiber connection and the actual fiber connection. A fiber-conn is mandatory. For more information on provisioning intra-nodal fiber connections, see Provisioning intra-nodal fiber connections.

    For example, to create a fiber-conn between the C2 port on the ROADM and the line port on the multiplexer/demultiplexer:

    bti7800(config)# dol fiber-conn port:1/6/0/C2 port:0/1/0/L1 bti7800(config-fiber-conn-port:1/6/0/C2/port:0/1/0/L1)# top
    Note

    This command assumes the C2 port of the ROADM module is connected to the multiplexer/demultiplexer. This is an example only. There is no restriction on which client port is used to connect to the multiplexer/demultiplexer.

    Note

    This type of fiber connection is not automatically provisioned.

  4. Configure the fiber connection between the multiplexer/demultiplexer and the physical UFM interface.

    The multiplexer/demultiplexer breaks out the DWDM wavelengths by client port, with each client port carrying a unique wavelength. You must specify the client port with the appropriate wavelength in this command. See BTI7800 DWDM Wavelength Plan for a mapping of frequency/wavelength to client port.

    For example, to create a fiber-conn between client port C33 (192.95THz) on the multiplexer/demultiplexer and an otu4 interface on a UFM:

    bti7800(config)# dol fiber-conn port:0/1/0/C33 otu4:1/10/2/1
    Note

    The otu4 interface in this command must be configured with the same frequency that is carried on client port C33 (that is, 192.95THz).

    Note

    This type of fiber connection is not automatically provisioned.

  5. Create the cross-connect.

    For example:

    bti7800(config)# dol och-xcon och:1/6/0/L1/chan295 otu4:1/10/2/1
  6. Commit the provisioning.
    bti7800(config-fiber-conn-port:0/1/0/C33/otu4:1/10/2/1)# commit
    Note

    The system automatically creates the optical channel (with the same channel name) on the ROADM client port (och:1/6/0/C2/chan295).

  7. If you have more add/drop connections to add, repeat 2 and 4 to 6.

Provisioning an Add/Drop Connection to an External Endpoint (Alien Wavelength)

Use this procedure to provision a bidirectional add/drop connection from a line span on a ROADM module to a local external endpoint. A wavelength that is added/dropped from the local NE to a local external endpoint is called an alien wavelength.

Prerequisites:

  • The ROADM module must be provisioned.

  • The client and line ports on the ROADM module must be created. The ROADM module ports are auto-created when the module is added.

  • The inter-nodal (line-side) fiber connections must be created. See Provisioning inter-nodal fiber connections.

Figure 12: Add/Drop Connection Example (Alien Wavelength)
Add/Drop Connection Example (Alien Wavelength)
  1. Enter configuration mode.
  2. Create the optical channel on the line port of the ROADM module.

    For example, to create an optical channel on the line port of a ROADM module in chassis 1, slot 6, with a frequency of 192.95THz and a name of chan295:

    bti7800(config)# dol och:1/6/0/L1/chan295 central-frequency 192.95

    The name is a character string that should be sufficiently meaningful to allow you to identify the channel. In this example, the last three digits of the frequency are used as part of the identifier.

  3. Configure the fiber connection between the ROADM module and the multiplexer/demultiplexer if a fiber connection does not already exist.

    Provisioning fiber-conn allows the BTI7800 to detect discrepancies between the configured fiber connection and the actual fiber connection. A fiber-conn is mandatory. For more information on provisioning intra-nodal fiber connections, see Provisioning intra-nodal fiber connections.

    For example, to create a fiber-conn between the C2 port on the ROADM and the line port on the multiplexer/demultiplexer:

    bti7800(config)# dol fiber-conn port:1/6/0/C2 port:0/1/0/L1
    Note

    This command assumes the C2 port of the ROADM module is connected to the multiplexer/demultiplexer. This is an example only. There is no restriction on which client port is used to connect to the multiplexer/demultiplexer.

    Note

    This type of fiber connection is not automatically provisioned.

  4. Create the cross-connect within the ROADM module and apply the changes.

    For example:

    bti7800(config)# dol och-xcon och:1/6/0/L1/chan295 och:1/6/0/C2/chan295
    Note

    The client port optical channel specified in this command is automatically created when this command is executed. You do not need to create the client port optical channel explicitly.

    Note

    Although this command creates an optical channel cross-connect between the ROADM line port and the specified ROADM client port, you cannot connect the external endpoint directly to the ROADM client port. You must connect the external endpoint to the appropriate client port on the multiplexer/demultiplexer. The line port on the multiplexer/demultiplexer is then connected to the ROADM client port.

After the provisioning is applied, the alien wavelength is cross-connected from the specified ROADM line port to the associated client port of the attached multiplexer/demultiplexer. You can now connect a fiber from the associated multiplexer/demultiplexer client port to the external endpoint. A fiber-conn between the multiplexer/demultiplexer and the external endpoint is not required.

Deleting a Pass-Through or Add/Drop Cross-Connect

Use this procedure to delete a pass-through or add/drop cross-connect.

  1. Enter configuration mode.
  2. Delete the cross-connect.

    In order to delete a cross-connect, you must delete both the cross-connect and the line port optical channel endpoint(s). You do not need to explicitly delete the client port optical channels because they are deleted automatically.

    The following shows an example of a cross-connect and the associated optical channel endpoints prior to deletion:

    bti7800(config)# do show dol och-xcon
    1. Delete the cross-connect.

      For example:

      bti7800(config)# no dol och-xcon och:1/8/0/L1/chan285 och:1/9/0/L1/chan285
    2. Delete all line port optical channel endpoints associated with the deleted cross-connect.

      This step is mandatory. Depending on the cross-connect, there is either one or two line port optical channel endpoints to delete.

      For example:

      bti7800(config)# no dol och:1/8/0/L1/chan285
      Note

      You cannot reuse line port optical channel endpoints. If you want to set up a new cross-connect on the same wavelength, you must delete and recreate the line port optical channel endpoints first. Failure to do so might lead to unpredictable behavior.

  3. Commit the provisioning.
    bti7800(config)# commit
    Note

    The system automatically deletes the client port optical channel endpoints.

Enabling or Disabling the OMS

Use this procedure to enable or disable the OMS.

The OMS represents the multiplexed signal (C-band). Enabling or disabling the OMS results in the following behavior:

Table 1: Effect of Enabling or Disabling OMS

Port on which the OMS is enabled or disabled

OMS Enabled

OMS Disabled

ROADM client port

Enables the OMS laser output.

Disables the OMS laser output.

ROADM line port

Enables the OMS laser output.

Disables the OMS laser output.

ILA client port

Enables the OMS laser output.

Disables the OMS laser output.

ILA line port

This command has no effect on the OMS laser output for this port. The OMS laser is always on (unless APSD is triggered).

  1. Enter configuration mode.
  2. Enable or disable the OMS.
    1. To enable the OMS:

      For example, on a line port:

      bti7800(config)# dol oms:1/8/0/L1 admin-status up bti7800(config-dol-oms:1/8/0/L1)#
    2. To disable the OMS:

      For example, on a line port:

      bti7800(config)# dol oms:1/8/0/L1 admin-status down bti7800(config-dol-oms:1/8/0/L1)#
  3. Apply the provisioning.
    bti7800(config-dol-oms:1/8/0/L1)# commit

Enabling or Disabling the PRE in the Optical Path

Use this procedure to enable or disable the PRE in the optical path.

Prerequisites:

  • The PRE module is created.

  • The host ROADM or ILA module is created.

The PRE module is used to provide supplementary amplification of the incoming line signal. Enabling or disabling the PRE in the optical path should only be performed in accordance with the optical network design.

Table 2 shows the span losses where a PRE must be enabled and disabled. If you enable or disable the PRE when you should not, the system raises a Loss Out of Specification Receive (loSpecRx) alarm.

Table 2: PRE Module Range

Span loss < 11dB

11dB < Span loss < 23dB

Span loss > 23dB

PRE must be disabled.

If PRE is enabled, a LoSpecRx alarm is raised.

PRE can be enabled.

The host module gain control adjusts automatically to the presence or absence of pre-amplification.

PRE must be enabled.

If PRE is disabled or not installed, a LoSpecRx alarm is raised.

Note

Enabling and/or disabling a PRE module is service affecting.

  1. Enter configuration mode.
  2. Enable or disable the PRE module.

    The PRE module can only be enabled or disabled on the host module line port.

    1. To enable the PRE module in the optical path:

      bti7800(config)# dol oms:1/8/0/L1 pre-state enabled

      The incoming line signal is passed to the PRE module for supplementary amplification.

    2. To disable the PRE module in the optical path:

      bti7800(config)# dol oms:1/8/0/L1 pre-state disabled

      The incoming line signal is no longer passed to the PRE module for supplementary amplification.

  3. Apply the provisioning.
    bti7800(config-dol-oms:1/8/0/L1)# commit

Optical Back Reflection on DOL OSC Entities

Optical back reflection refers to the amount of light that is reflected back up the fiber toward the source. Caused by the reflection of light where the polished end surface of the fiber connector and the surrounding air interface, optical back reflection can indicate a poor fiber connection.

DOL line OSC entities (osc:<chassis>/<slot>/0/L1) support the following optical back-reflection ratio statistics, which help in the detection of compromised fiber connections:

  • Optical back-reflection ratio

  • Minimum optical back-reflection ratio

  • Maximum optical back-reflection ratio

  • Average optical back-reflection ratio

  • Standard deviation from optical back reflection ratio

Note

Optical back reflection counters are supported starting with release 4.1.

To retrieve optical back-reflection ratio statistics for an OSC entity, use the show statistics current CLI command. For example:

bti7800# show statistics current osc:1/8/0/L1

Optical Back Reflection High Threshold Alarm

The Optical Back Reflection High Threshold (obrHt) alarm is raised against a DOL line OSC entity when the optical back-reflection ratio exceeds the alarmHigh threshold value, and then clears when the ratio falls below that value (see Table 3).

Table 3: Default OSC Back-Reflection Ratio Threshold Values (obrHt Alarm)

Threshold

Bin

Parameters

Values

Status

Range

Default

alarmHigh

UnTimed1

RaiseValue

-37 to -6

-18 dB

Enabled

ClearValue

-37 to -6

-19 dB

alarmLow

warningAlert

1 Only the unTimed bin is supported.

If required, you can configure a customized optical back-reflection ratio threshold profile and assign it to one or more DOL line OSC entities. For information, see Configuring a customized optical back-reflection ratio threshold profile.

Note

The obrHt alarm can be raised only while the alarmHigh unTimed threshold bin is enabled.

For more information about the obrHt alarm, see the BTI7800 Series Alarm and Troubleshooting Guide.

Configuring a Customized Optical Back-Reflection Ratio Threshold Profile

Use this procedure to configure a customized optical backreflection ratio threshold profile and assign it to a DOL line OSC entity.

Note

Configure a customized optical back-reflection ratio threshold profile only if required. For information about the default threshold values, see Optical Back Reflection High Threshold Alarm .

  1. Set up the statistics threshold profile for the OSC entity type, specifying values for the raise (RaiseValue) and clear (ClearValue) parameters of the alarmHigh unTimed bin.Note

    Juniper Networks recommends that the difference between the RaiseValue and ClearValue threshold values be 1 dB; for example RaiseValue = -21 dB and ClearValue = -22 dB. Specifying threshold values less than 1 dB apart might cause the obrHt alarm to toggle.

    For example:

    bti7800 config
    Note

    The alarmHigh unTimed bin is enabled by default.

  2. Assign the statistics threshold profile to a DOL line OSC entity. For example:
    bti7800(config)# statistics threshold entity osc:1/8/0/L1 profileName obrProf1
  3. Repeat step 2 for each OSC entity that you want to apply the threshold profile.
  4. Verify the configuration.
    bti7800 show running-config statistics

ROADM Performance Monitoring

Table 4 and Table 5 list ROADM performance monitoring counters. See the following topics for counter definitions:

Table 4: Module Statistics

Counter

ILA module

ROADM module

PRE module

cpu-load-avg

Yes

Yes

cpu-load-min

Yes

Yes

cpu-load-max

Yes

Yes

Table 5: Optical Statistics

Counter

Client port

Line port

PRE port on host

PRE port on PRE

osc

oms

och

opt-back-ref-ratio1

No

Yes

No

No

Yes

No

No

opt-back-ref-ratio-min1

No

Yes

No

No

Yes

No

No

opt-back-ref-ratio-max1

No

Yes

No

No

Yes

No

No

opt-back-ref-ratio-avg1

No

Yes

No

No

Yes

No

No

opt-back-ref-ratio-std-avg1

No

Yes

No

No

Yes

No

No

opr

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opr-min

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opr-max

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opr-avg

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opr-std-avg

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opt

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opt-min

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opt-max

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opt-avg

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opt-std-avg

Yes

Yes

Yes

Yes

Yes

Yes

Yes

opl-rx

Yes2

Yes

Yes

Yes

No

No

No

opl-rx-min

Yes2

Yes

Yes

Yes

No

No

No

opl-rx-max

Yes2

Yes

Yes

Yes

No

No

No

opl-rx-avg

Yes2

Yes

Yes

Yes

No

No

No

span-lngth

No

Yes

No

No

No

No

No

1 The optical back reflection counters are supported starting with release 4.1.

2 On client pass-through ports only. Otherwise, no. A client pass-through port is a client port that carries pass-through traffic.

ROADM Network Engineering

The ROADM network implementation should be based on the ROADM network design. Contact Juniper Networks if you require help with the design of your ROADM network.

Release History Table
Release
Description
opt-back-ref-ratio
opt-back-ref-ratio-min
opt-back-ref-ratio-max
opt-back-ref-ratio-avg
opt-back-ref-ratio-std-avg