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TCX1000-2D8CMD Colorless Multiplexer-Demultiplexer Overview

 

The TCX1000-2D8CMD is a simple and low cost port expander that uses a combiner-splitter architecture. The TCX1000-2D8CMD is housed in industry standard LGX cassettes that you can flexibly mount in 1RU, 3RU, or 4RU passive chassis solutions.

TCX1000-2D8CMD Overview

The TCX1000-2D8CMD is a colorless, two-directional optical multiplexer-demultiplexer that provides eight colorless client ports and two line ports. You can use the TCX1000-2D8CMD to expand the number of channels you can support on the TCX1000-RDM20. For example, by connecting the TCX1000-2D8CMD to a single universal port on the TCX1000-RDM20, you can switch an additional eight channels through the TCX1000-RDM20 using only a single universal port, while still maintaining the spectrally programmable (colorless) operation and using the minimum numbers of universal ports on the TCX1000-RDM20, allowing for future expansion.

Client Ports

You connect your transceivers to the eight client ports on the TCX1000-2D8CMD labeled Cx In and Cx Out.

Note

The combiner-splitter architecture of the TCX1000-2D8CMD requires you use only coherent transceivers.

Channels received from the line ports of the TCX1000-2D8CMD are broadcast to all eight client ports. The coherent transceivers connected to the client ports are responsible for selecting their corresponding wavelength and filtering out the impact of the unwanted broadcast channels.

The TCX1000-2D8CMD has no optical filtering. If channels with overlapping spectral usage are presented on the client ports of the same TCX1000-2D8CMD, interference occurs between the channels. You cannot add/drop multiple channels that are the same wavelength to the TCX1000-2D8CMD client ports. If two or more channels at the same wavelength are added to the TCX1000-2D8CMD, channels collide causing transmission impairment of the overlapping channels. You must take care to ensure that these collisions do not happen; this is not enforced by the hardware. However, if the proNX Optical Director detects this situation, it reports an alarm.

Line Ports

The TCX1000-2D8CMD has two line ports. Channels present on the client ports are combined and sent out both line ports simultaneously.

You can connect the line ports of the TCX1000-2D8CMD to the TCX1000-RDM20 universal ports to provide either:

Single Direction Add/Drop Colorless Multiplexing

Figure 1 shows a single direction ROADM node that supports single direction add/drop colorless multiplexing-demultiplexing. This example uses only one of the line ports on the TCX1000-2D8CMD.

Looking at Figure 1 from left to right: transceivers connect to the client (Cx In and Cx Out) ports of the TCX1000-2D8CMD, whose line port (L0 IN and L0 OUT) connects to a single universal port on the TCX1000-RDM20.

All channels present on the TCX1000-2D8CMD are combined and sent out the line port to the universal port on the TCX1000-RDM20, which multiplexes these channels, along with any channels directly connected to its universal ports and sends them out the line port of the TCX1000-RDM20.

Figure 1: Single Direction ROADM Node Add/Drop Colorless Multiplexing
Single Direction ROADM Node Add/Drop
Colorless Multiplexing

1 + 1 Redundancy

Figure 2 shows a 2-degree ROADM node that provides 1 + 1 redundancy for the channels connected to the TCX1000-2D8CMD. The node consists of two TCX1000-RDM20s and one TCX1000-2D8CMD. The software configuration of the connecting TCX1000-RDM20s control the selection of which channels are routed to/from each ROADM line port.

Figure 2: Summary Colorless 1+1 Redundancy Multiplexing in ROADM Node
Summary Colorless 1+1 Redundancy
Multiplexing in ROADM Node

In this ROADM node, one of the line ports on the TCX1000-2D8CMD connects to TCX1000-RDM20 serving the west direction (degree) and the other line port connects to TCX1000-RDM20 serving the east degree. By connecting to both TCX1000-RDM20 devices, the TCX1000-2D8CMD has add/drop access to wavelengths in both directions, which is a prerequisite to setting up a service with redundant paths.

The TCX1000-2D8CMD broadcasts the identical composite line signal out both line ports simultaneously and the connecting TCX1000-RDM20 is responsible for selecting which channels are sent through to the TCX1000-RDM20 line ports. The selection and routing of the channels is dynamically controlled through the proNX Optical Director.

Note

The TCX1000-2D8CMD has no optical filtering; the identical composite line signal is broadcast out both Line ports of the TCX1000-2D8CMD simultaneously and it is the responsibility of the connected TCX1000-RDM20 to select and route the channels through to the Line port.

The drop (demultiplexing) side of the TCX1000-RDM20 is responsible for selecting the channels destined to the TCX1000-2D8CMD and routing the channels to the correct universal port and line port on the TCX1000-2D8CMD.

Both TCX1000-2D8CMD line port paths cannot be active at the same time because the TCX1000-2D8CMD does not perform any switching; it simply broadcasts the channels.

Operation

The Drop (demultiplexing) side of the TCX1000-RDM20 is responsible for selecting which channels are sent to the receiving TCX1000-2D8CMD line port. The TCX1000-2D8CMD broadcasts the received channels to all client ports where the connected transceivers are responsible for selecting their corresponding wavelength and filtering out the impact of the unwanted broadcast channels. As such, the TCX1000-2D8CMD is suitable for coherent only applications.

The Add (multiplexing) side of the TCX1000-RDM20 is responsible for receiving the composite line signals from the TCX1000-2D8CMD on its universal ports and multiplexing the composite line signal, along with any channels directly connected to the universal ports, and sending the composite WDM signal out its line port on to the fiber system.

Note

The TCX1000-2D8CMD has no optical filtering. If channels with overlapping spectral usage are presented on the client ports of the same TCX1000-2D8CMD, interference occurs between the channels. You cannot add/drop multiple channels that are the same wavelength to the TCX1000-2D8CMD client ports. If two or more channels at the same wavelength are added to the TCX1000-2D8CMD, channels collide causing transmission impairment of the overlapping channels. You must take care to ensure that these collisions do not happen; this is not enforced by the hardware. However, if the proNX Optical Director detects this situation, it reports an alarm.

Calculating the TCX1000-2D8CMDs Required for Your Configuration

This section is meant to help you understand and determine the number of devices you need for your particular configuration.

Example 1

For the first example, assume that you need to support 16 channels and you want to do so using the fewest number of universal ports on the TCX1000-RDM20 so that you can leave ports for future expansion. You can create this configuration using the TCX1000-2D8CMD as follows:

  • Two TCX1000-2D8CMD (8 ports x 2=16 ports)

  • One TCX1000-RDM20

In this example, you connect the 16 transceivers to the client ports on the two TCX1000-2D8CMD multiplexers and you connect only one of the line ports from each TCX1000-2D8CMD to a universal port on the TCX1000-RDM20. This leaves you 18 universal ports on the TCX1000-RDM20 for future expansion (20 ports total - 2 ports=18 ports). This enables the transport of 16 colorless channels while using only a single universal port.

Example 2

For the second example, assume that you need to support 48 channels and you want to do so using the fewest number of universal ports on the TCX1000-RDM20 so that you can leave ports for future expansion. You can create this configuration using the TCX1000-2D8CMD as follows:

  • Six TCX1000-2D8CMD (8 ports x 6 = 48 ports)

  • One TCX1000-RDM20

The six TCX1000-2D8CMDs provide a total of 48 ports for transceiver connections. One of the line ports from each TCX1000-2D8CMD connects to a universal port on the TCX1000-RDM20, using a total of 6 universal ports. This leaves you 14 free universal ports on the TCX1000-RDM20 for future expansion.