dynamic synchronous transfer mode (DTM)

Dynamic Synchronous Transfer Mode (DTM) is a broadband network technology developed by the Swedish company Dynarc based on time division multiplexing(TDM) and dynamic circuit switching. DTM is intended to combine the advantages of traditional telecommunications with the mechanisms of modern data communications to provide improved QoS services in fiber optic networks.

With DTM, connections are established separately from data packet switching, so traffic flows do not affect each other. Signaling and data traffic are also separate from each other. Control information is processed only during connection establishment and termination. To increase throughput, the DTM method has no traffic flow control.

The TDM and space division multiplex( SDM) used in the DTM method are based on a simple circuit switching technique. Here, DTM uses the same frame structure as Synchronous Digital Hierarchy( SDH) and Synchronous Optical Network( SONET). The transmission time is 125 µs per frame. DTM is located on the lower three layers of the OSI reference model and, unlike Synchronous Digital Hierarchy (SDH), uses a signaling protocol. Nevertheless, DTM can be used in an SDH infrastructure, where DTM data streams can be transported over SDH. The transmission channels and switching are located at the DTM layer.

The DTM structure is less complex, only a small portion of the time slots are used for control information, and the overhead is 1%.

A DTM channel can be considered as a dynamic resource, which can be scaled up in steps of 512 kbit/s up to the full capacity of up to 1 Gbit/s. Further scaling is planned. Each channel occupies a fixed number of time slots, which becomes via control time slots. This number can be varied so that the bandwidth requirement can be dynamically adapted to the data volume. the DTM channel is transparent for IP packets, multimedia or voice data.

DTM is a proprietary process that is not standardized.