[WDM Basics] OTN Tributary Boards and Line Boards Highlighted

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OTN Tributary Boards and Line Boards

Huawei OTN product series support the use of separate tributary and line boards.

Tributary and line boards work with cross-connect boards.

A tributary board plus a line board together performs the functions of an OTU board.

Different from an OTU board, the tributary and line boards achieve more flexible and fine-grained grooming of electrical services and offers a higher bandwidth utilization by working with a cross-connect board.

OTN Tributary Boards

Function：OTN tributary boards are used mainly to locally add/drop client services from the WDM side.

Specifically, an OTN tributary board receives a client service, converts the service into an electrical signal, maps the signal into an appropriate ODUk signal, and sends the ODUk signal to the cross-connect board.

Positions of OTN tributary boards in a WDM system:

OTN Line Boards

Function：

• Allows for local add/drop of client services on the WDM side by working with an OTN tributary board.

Specifically, the OTN tributary board receives a client service, converts the service into an electrical signal, maps the signal into an appropriate ODUk signal, and sends the ODUk signal to the cross-connect board for grooming. When the OTN line board receives the ODUk signal from the cross-connect board, it maps and multiplexes the signal and converts the signal into an OTUk signal carried over an ITU-T G.694.1-compliant DWDM wavelength. The reverse conversion is similar.

• Transparently transmits WDM-side services by working with another OTN line board.

When receiving a west WDM-side service, this OTN line board performs E/O conversion, demapping, and demultiplexing to convert the service into an ODUk signal. Then this OTN line board sends the ODUk signal to the cross-connect board for grooming. When the other OTN line board receives the ODUk signal from the cross-connect board, it converts the ODUk signal into an OTUk signal carried over an ITU-T G.694.1-compliant DWDM wavelength by performing mapping, multiplexing, and E/O conversion, and sends the OTUk signal to the east. The reverse process is similar.

Positions of OTN line boards in a WDM system:

OTU boards can be used to add client-side services to the WDM side. Why the tributary/line separated architecture is needed?

As shown in the preceding figures, the major difference between the tributary/line separated architecture and the OTU architecture lies that centralized cross-connect boards are introduced into the tributary/line separated architecture for grooming of ODUk signals at different levels. To be specific, under the tributary/line separated architecture, client-side services are not encapsulated into WDM-side services (OTUk) and added to the line side using one board.This architecture improves electrical-layergrooming flexibility and bandwidth usage.

Reference: https://info.support.huawei.com/onlinetoolweb/resources/en/25_zhiluban.html

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