Traffic grooming


Traffic grooming is the process of grouping many small telecommunications flows into larger units, which can be processed as single entities. For example, in a network using both time-division multiplexing and wavelength-division multiplexing, two flows which are destined for a common node can be placed on the same wavelength, allowing them to be dropped by a single optical add-drop multiplexer. Often the objective of grooming is minimizing the cost of the network. The cost of line terminating equipment is the most dominant component in an optical WDM network's cost. Thus grooming typically involves minimizing the usage of ADMs.
This is similar to the use of virtual channels and virtual paths in ATM networks.
Effective grooming requires consideration of the topology of the network and the different routes in use. This is especially useful when dealing with mesh networks.

Grooming Algorithms

The traffic grooming problem has proven to be computationally intractable in the general case. Hence heuristic solutions are typically used.

Electrical-Layer Grooming

Grooms electrical signals at a granularity of ODUk.
Grooms optical signals at a granularity of wavelength by flexibly selecting transmission paths.