Cell Relay is a newer approach to data networks. The cell is the data unit. In order to support voice, the data units must be small so that they can be processed quickly and sent through the network with minimal delay. This is not true with data, which favors large data units. Voice requires small data units, and data favors large data units.

In a cell relay network, the facility is used when needed. Whenever there is information to be transmitted, the switch simply sends the data units. There is no need to negotiate for a connection (as is the case in circuit switching), there is no need for a channel to be allocated (there are no channels in ATM), and as long as there is enough bandwidth to support it, there can be unlimited transmissions over the same facility.

Copied with permission,McGraw-Hill Telecommunications from the book Telecommunications Protocols, by Travis Russell, 1997 McGraw-Hill Telecommunications, pages 45-48.