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proNX Optical Director Links and Services Overview

 

All TCX1000 Series devices are configured and managed by proNX Optical Director. This topic describes the basic concept of links and services for the TCX Series Optical Transport System. It includes the following subjects:

Links

Links Overview

Configuring and learning device links allows the proNX Optical Director to have a view of the topology of the optical network, which is a prerequisite for managing optical services. An accurate view of the topology allows the proNX Optical Director to dynamically control the optical links in your network and to determine the available service paths for the services that you subsequently create. In order to build the topology, the proNX Optical Director needs to know how devices are connected together, including knowledge of the device links within a ROADM node, the device links between ROADM nodes, the device links between amplifier sites, and the device links between ROADM nodes and amplifier sites. See Table 1 for definitions of terms used in this section.

Table 1: Optical Network Glossary

Term

Definition

Amplifier site

A site containing a line amplifier device providing amplification of the incoming composite DWDM signals. An example of a line amplifier device is the TCX1000-ILA, which is an inline amplifier that provides amplification in both directions.

Device link

A link between any two managed devices. Device links represent the actual fibers installed between devices in your network.

Line span

A device link connecting the line ports of two devices together.

Tail facility

The link from the optical network edge to the client transponder. See Table 4 and Table 3.

Topology

The ROADM topology, which is the topology concerned with how ROADM nodes are connected together, and consequently, how wavelengths are allocated in the network.

Note: The ROADM topology models an amplifier site as part of a line because line amplifiers operate on the composite DWDM signal and not on the individual wavelengths.

Figure 1 shows an example of how devices can be connected together in a 2-degree ROADM node. A 2-degree ROADM node contains two ROADM elements, with each ROADM element connected to a line (or degree). These ROADM elements are labelled A and B in the example.

ROADM Element A consists of a TCX1000-RDM20 and a 2D8CMD. The 2D8CMD connects to a universal port on the TCX1000-RDM20 in ROADM Element A and can optionally connect to a universal port on the TCX1000-RDM20 in ROADM Element B. By connecting to both TCX1000-RDM20 devices, the 2D8CMD has add/drop access to wavelengths on both degrees, which is a prerequisite to setting up a service with working and protection paths.

In contrast, ROADM Element B just consists of a TCX1000-RDM20, so it only has add/drop access to wavelengths on the line that it is attached to. The reason for this is that the TCX1000-RDM20 can only switch wavelengths between its universal ports and its line port. It cannot switch wavelengths from one universal port to another.

Figure 1: 2-Degree ROADM Node Example
2-Degree ROADM Node Example

The endpoint or client transponder can be a standalone device or integrated within a router or a switch. The endpoint transponder can connect to the ROADM node in a couple of different ways. One way is to connect the endpoint transponder to a client port on the 2D8CMD in ROADM Element A to provide add/drop access to both degrees. By doing this, you can then set up a service with both working and protection paths through the network. The second way is to connect the endpoint transponder directly to a universal port on the TCX1000-RDM20 in either ROADM Element A (not shown) or ROADM Element B to provide add/drop access to the degree to which the TCX1000-RDM20 is attached.

The device links to the endpoint transponders are known as tail facilities, which are the connections between the optical network edge and the client device. The proNX Optical Director can be used to provision tail facility links to supported ports on Juniper Networks equipment as well as to provision the endpoints themselves. See Table 3 and Table 4 for the list of the tail facility endpoints that the proNX Optical Director can configure.

Device links within a ROADM node and from a ROADM node to a tail facility endpoint must be manually provisioned.

Device links between ROADM nodes, between amplifier sites, and between ROADM nodes and amplifier sites, can be learned depending on which release of the proNX Optical Director and TCX1000-RDM20 you are running. These device links are called line spans because they connect to the line ports of the devices.

Provisioned Device Links

A provisioned device link is a device link that you explicitly create. A provisioned device link where both endpoints are within the same ROADM element is called a physical link. A provisioned device link where one endpoint resides outside the ROADM element is called an external link. For more information on external and physical links, see http://www.openroadm.org.

Note

In Juniper Networks’ implementation, only device links that are provisioned have a physical or external type designation. Auto-learned device links are not associated with a link type.

It is important that your configured device links match the actual device links or unexpected behavior can occur.

Note

When you provision a device link to a ROADM port, the ROADM port is automatically placed in-service administratively. You do not need to manually place the port in-service.

Auto-Learned Device Links

Automatic learning of line spans is supported if you are running proNX Optical Director release 2.2 or higher and the devices in your network are running the following releases:

  • TCX1000-RDM20 running release 3.1 or higher

  • TCX1000-ILA running any release

The proNX Optical Director learns about the existence of line spans based on the Link Layer Discovery Protocol (LLDP) neighbor information that the devices report. While the proNX Optical Director can determine the neighbors from this data, it cannot determine the type of fiber used for the span because the type of fiber used cannot be automatically detected. Instead, the proNX Optical Director assumes a default fiber type for all line spans in the network.

Note

If this default fiber type is different from the actual fiber type for a particular span, you will need to manually configure the fiber type for that span.

To change the fiber type, you have to create an external link based on the auto-learned link and then change the fiber type of the external link. The proNX Optical Director does not allow you to change the fiber type of an auto-learned device link directly because auto-learned data originates from the device and is read-only. For convenience, the proNX Optical Director user interface lets you perform this task as if you are editing the fiber type.

Nevertheless, it is important for you to be aware that when you change the fiber type of an auto-learned device link, you are actually creating a separate external link and assigning a fiber type to that external link. When the proNX Optical Director sees an external link and an auto-learned link sharing the same two endpoints, the proNX Optical Director uses the fiber type provisioned for the external link.

If you later physically unplug the fiber associated with the auto-learned device link, the auto-learned designation disappears from the table (in the Device Links Current page), but the entry remains to represent the newly created external link. You can delete this external link just like you can delete any other external link.

Note

Unlike a provisioned link, an auto-learned link to a ROADM port does not automatically place the ROADM port administratively in-service. You will need to manually place the port in-service or create the external link for the line span. One way of creating the external link is to edit the fiber type.

Link Validation

The proNX Optical Director validates device links for network-wide consistency. The following provisioning inconsistencies are detected and alarmed:

  • Two or more device links share the same endpoint (that is, a port has a link to more than one device). The proNX Optical Director displays the inconsistent links in the table in the Device Links Current page. The inconsistent links are considered invalid and are not considered part of the topology.

  • An auto-learned line span does not match the provisioned (expected) line span. The proNX Optical Director displays the inconsistent links in the table in the Device Links Current page. The auto-learned line span is considered valid and part of the topology. The provisioned (expected) line span is considered invalid and is therefore not part of the topology.

Supported Optical Links

Table 2 describes the allowed link endpoint combinations.

The source and destination designations are used only to distinguish between the two link endpoints. They are assigned arbitrarily and are interchangeable.

Source Link Endpoint

Destination Link Endpoints

Notes

A line port on a TCX1000-RDM20 or a TCX1000-ILA

A line port on a TCX1000-RDM20 or a External TCX1000-ILA

Note: You can cascade up to four TCX1000-ILAs in an amplifier chain.

Universal port on TCX1000-RDM20

Universal port on a co-located TCX1000-RDM20 in a multi-degree note

Note: This is a fiber connection used for channel pass-through between ROADM elements in a multi-degree ROADM node.

Universal port on TCX1000-RDM20

A line port on a TCX1000-2D8CMD optical multiplexer-demultiplexer

Enables 8 channels from the TCX1000-2D8CMD to be multiplexed over a single universal port on the TCX1000-RDM20.

Universal port on TCX1000-RDM20

A line port on a BTI7800-FMD96 fixed optical multiplexer-demultiplexer

Enables up to 96 x 200 Gbps coherent channels from the BTI7800-FMD96 to be multiplexed over a single universal port.

The FMD96 is a fixed channel multiplexer/demultiplexer, which means that each client port is associated with a hardcoded fixed wavelength. When you create a link between an FMD96 client port and a tail facility endpoint, you must ensure that the tail facility endpoint is configured with a wavelength that matches the wavelength of the client port on the FMD96.

A universal port on a TCX1000-RDM20

A supported tail facility endpoint on Juniper Networks equipment.

See Table 4.

A client port on an FMD96 or on a 2D8CMD

A supported tail facility endpoint on Juniper Networks equipment.

See Table 4.

Services

Services Overview

An optical service provides wavelength connectivity between optical service endpoints and exists as a series of individual optical cross-connects that route the service wavelength through the multiplexers/demultiplexers, ROADMs, and line amplifiers that make up the optical network. The proNX Optical Director encapsulates this series of cross-connects into a single entity for presentation to the user.

Attached to each end of the optical service is the endpoint transponder. The endpoint transponder can be a standalone transponder or a transponding function integrated on packet equipment.

The connection between the endpoint transponder and the optical network edge is called the tail facility. The tail facility endpoint (that is, transponder) is not part of the optical network, but you can use the proNX Optical Director to configure the tail facility endpoint if the tail facility terminates on a supported transceiver port on Juniper Networks equipment. This is called a supported tail facility endpoint.

If the tail facility does not terminate on a supported transceiver port, the tail facility endpoint is known as an external or alien endpoint. You can connect an alien endpoint to the optical network but you will need to configure the alien endpoint using the external equipment’s management system.

When you create an optical service using the proNX Optical Director, you specify the wavelength and the two endpoints that the wavelength interconnects. The endpoint that you specify can be an optical service endpoint (that is, an optical port at the optical network edge) or a supported tail facility endpoint:

  • If the service connects to a supported tail facility endpoint, then you can specify the tail facility endpoint directly when you create the service. The proNX Optical Director automatically determines where the optical service endpoints are based on the configured device links and sets up the optical service between the optical service endpoints.

  • If the service connects to an alien endpoint, then the endpoint you specify is the optical port that attaches to the alien endpoint at the optical network edge. This can be a topologically-unconnected universal port on a TCX1000-RDM20 if the alien device is attached directly to that port, or a universal port on a TCX1000-RDM20 that is topologically connected to a multiplexer/demultiplexer. In this latter case, the alien device is attached to a client port on the multiplexer/demultiplexer.

Optical Service Endpoints and Tail Facility Endpoints

This section describes two types of endpoints: the optical service endpoint and the tail facility endpoint.

The optical service endpoint refers to the port at the optical network edge that connects to the client transponder. This endpoint is part of the optical network.

The tail facility endpoint is the port on the client transponder that connects to the optical network edge. This endpoint is a client or a user of the optical network.

Figure 2 and Table 3 describe the allowed endpoints when you create a service. You can create a service from endpoints A, B, C, or D to endpoints E, F, G, or H.

Figure 2: Optical Service Endpoints
Optical Service Endpoints

Table 3: Optical Service and Tail Facility Endpoints

Endpoint

Label

Usage

An optical service endpoint where the endpoint is a topologically-unconnected universal port on a TCX1000-RDM20.

This is a universal port that does not have a link associated with it.

A or E

You typically use this endpoint when you set up a service to an alien device that is attached directly to a universal port on the TCX1000-RDM20.

An optical service endpoint where the endpoint is a universal port on a TCX1000-RDM20 that is topologically connected to a multiplexer/demultiplexer.

This is a universal port that has a link to a multiplexer/demultiplexer.

B or F

You typically use this endpoint when you set up a service to an alien device that is attached to a client port on the multiplexer/demultiplexer.

A supported tail facility endpoint where the endpoint is topologically connected to a universal port on a TCX1000-RDM20.

This is a transceiver port at the supported tail facility endpoint.

C or G

You typically use this endpoint when you set up a service to a supported tail facility endpoint that is attached directly to a universal port on the TCX1000-RDM20.

A supported tail facility endpoint where the endpoint is topologically connected to a client port on a multiplexer/demultiplexer.

This is a transceiver port at the supported tail facility endpoint.

D or H

You typically use this endpoint when you set up a service to a supported tail facility endpoint that is attached to a client port on the multiplexer/demultiplexer.

The TCX1000-RDM20 has a pool of 20 universal ports that you can use to connect to other ROADM elements and/or to client transponders. For lower wavelength fan-out, you can deploy the TCX1000-RDM20 without a multiplexer/demultiplexer and use any available universal ports to connect directly to client transponders (labels A, C, E, G). For larger wavelength fan-out, you can deploy the TCX1000-RDM20 alongside a multiplexer/demultiplexer to give access to more wavelengths (labels B, D, F, H).

When creating a service to an alien tail facility endpoint, the endpoint you specify resides in the optical network (labels A, B, E, F) and does not include the tail facility itself. It is your responsibility to ensure that the alien endpoint is configured properly to connect to the optical network at those points.

When creating a service to a supported tail facility endpoint, the endpoint that you specify is the supported port on Juniper Networks equipment (labels C, D, G, H in Figure 2). SeeTable 4 for the list of supported tail facility endpoints.

Creating a service for a supported tail facility listed Table 4 in:

  • Includes control and configuration of endpoint transceiver(s)

  • Sets up of the service, such a 100 Gbps Ethernet transport including wavelength

  • Opens the optical path through network to allow transport of channel

  • Opens the optical path and brings it under control for performance optimization

  • Creates the service, for example from router port to router port

See Figure 2 and Table 3 for the allowed endpoints when you create a service. You can create a service from A, B, C, or D to E, F, G, or H.

For lower wavelength fan-out, you can deploy the TCX1000-RDM20 without a multiplexer-demultiplexer and use the universal ports to connect directly to client transponders (labels A, C, E, G in Figure 2). For larger wavelength fan-out, you can deploy BTI7800-FMD96 fixed multiplexer-demultiplexer to give access to all 96 wavelengths concurrently (labels B, D, F, H in Figure 2). Or, for a colorless, flex grid ready solution, you can use twelve TCX1000-2D8CMD colorless multiplexers with a single TCX1000-RDM20 to provide 96 wavelength access.

Table 4 shows the Juniper Networks compatible tail-facility service endpoints that the proNX Optical Director supports.

Table 4: Juniper Networks Compatible Tail-Facility Service Endpoints

Client Device

Juniper Networks Compatible Service Tail Facility Endpoints

BTI7800

Ports on the UFM3 (BT8A78UFM3) 100G Coherent CFP-M05 transceiver (CFP-100GBASE-CHRT)

Ports on the UFM6 (BT8A78UFM6-I02) 400G Coherent MSA XCVR

ACX6360

Ports on the CFP2-DCO transceiver (CFP2-DCO-T-WDM-1)

MX Series router

  • Ports on MPC5E-100G10G, MPC5EQ-100G10G adapter cards that support QSFP+

  • Ports on MPC6 (MX2K-MIC6-2CE-CFP2) adapter cards that support CFP2

PTX Series router

  • Ports on the 100-Gigabit DWDM OTN PIC with CFP2-ACO (PTX-5-100G-WDM)

  • Ports on the P2-100GE-OTN PIC with the CFP2-DCO-T-WDM-1 pluggable transceiver

QFX Series switch

Ports on the QFX10K DWDM 1.2 Tbps line card (QFX10K-12C-DWDM)

Single Path Service

A single path service is a service that has a single path set up between the two service endpoints. A fault on the path might cause the service to go down.

Protected Service

Figure 3 shows a protected service using a pair of two-degree ROADM nodes connected in a basic two-node ring. More complex ring and mesh configurations are possible as well.

Figure 3: Protected Service
Protected Service

A protected service is a service that has a pair of paths set up between the two service endpoints. One path is placed administratively in-service (IS) and the other path is placed administratively out-of-service (OOS). Under normal conditions, the IS path provides the optical connectivity. If a fault occurs in the current IS path, you can manually restore service by administratively disabling the current IS path and administratively enabling the current OOS path so that the current OOS path becomes the new IS path. This is called manual restoration by changing a. service’s administrative state.

Note

It is up to the operator to ensure that one path is administratively in-service and the other path is administratively out-of-service. The proNX Optical Director does not enforce this but will raise an alarm if both paths are in-service.

A multi-degree colorless multiplexer/demultiplexer such as the TCX1000 2-Degree 8-Channel Colorless Mux/Demux (2D8CMD) is required at each end as the common endpoint for the protected service. The 2D8CMD has two line ports (L0 and L1) that connect to the two different degrees in the ROADM node, thereby supporting two paths between the endpoints.

A protected service is modeled as a pair of services where each service in the pair takes a different path across the network. The individual services in the pair are effectively single path services that share a common wavelength and common endpoints.

There are two ways to set up a protected service in the proNX Optical Director:

  • You can configure the IS path and let the proNX Optical Director determine and configure the OOS path. This is the easier method.

  • You can configure a single path service for the IS path and separately configure a single path service for the OOS path. The proNX Optical Director is then able to determine that you have created a protected service because the single path services that you created share the same wavelength and the same endpoints.

Orphan Service

An orphan service is a service without two add/drop endpoints. If you see an orphan service displayed, it is an indication that you have misconfigured the ROADM topology or otherwise altered the ROADM topology (such as unplugging and plugging fibers to different devices when LLDP is enabled) after the service is created.

The proNX Optical Director only allows you to create an optical service if a path exists between the two add/drop endpoints at the time that you create the service. If, after you create the service, you change the ROADM topology (such as by deleting links or undiscovering ROADM devices) such that the original path no longer exists between the two endpoints, the proNX Optical Director shows the service as two orphan services, one for each endpoint.

The reason for this is that, after the ROADM topology change, the proNX Optical Director cannot reconcile the intended service path with the new ROADM topology and therefore cannot display the full service path. It is only able to display the path from each endpoint to where the topology is broken. Note that this behavior can be different for a cut fiber. In the case of a cut fiber on a line span, the proNX Optical Director still knows where the intended path is as long as the associated external link is provisioned. In this case, the service is shown with a link that is down, and not as a pair of orphan services.

When you fix the ROADM topology, the proNX Optical Director will display the service correctly once again.

To prevent this from happening, ensure you do not change the ROADM topology after you create the service.