What is the basic principle behind Dynamic synchronous transfer mode (DTM)?

- Dynamic synchronous transfer mode or DTM is one of the most interesting of all the networking technologies. 

- The basic objective behind implementing this technology is to achieve high speed networking along with the transmissions of top quality.

- It also possesses the ability of adapting the bandwidth in varying traffic conditions quickly. 

- DTM was designed with the purpose of being used in integrated service networks including both the one to one communication and distribution.

- Furthermore, it can be used in application to application communication. 

- Nowadays, it has also found its use as a carrier for IP protocols (i.e., high layer protocols). 

- DTM is a combination of 2 basic technologies namely packet switching and circuit switching. 

- It is because of this that the DTM has many advantages to offer. 

- It also comes with a number of services access solutions for the following fields:

Ø  City networks

Ø  Enterprises

Ø  Residential as well as other small offices

Ø  Content providers

Ø  Video production networks

Ø  Mobile network operators

Principles of Dynamic synchronous transfer mode (DTM)

 

- This mode has been designed to work up on a unidirectional medium. 

- This medium also supports multiple access i.e., all the connected nodes can share it. 

- It can be built up on various topologies such as:

1. Ring
2. Double ring
3. Point – to – point
4. Dual bus and so on.

- TDM or time division multiplexing is what up on which the DTM is based. 

- Here, a fiber link’s transmission capacity is broken down in to smaller units of time. 

- The total link capacity is broken down in to frames of fixed size of 125 microseconds. 

- The frames are then further subjected to division in to time slots of 64 bit. 

- How many time slots will be there in one frame is determined by its bit rate. 

- These time slots consist of many separate control slots and data slots. 

- In some cases more control slots might be required, then the data slots can be turned in to control slots or vice versa.

- The nodes that are attached to the link possess the right to write both the kinds of slots. 

- As a consequence of this, same time slot position will be occupied by the all the time slots within each frame. 

- Each node possesses the right to at least one slot which can be used by the node for transmitting control messages to the other nodes. 

- These messages can also be sent when requested by the user as a response to messages sent by the other nodes or for some purpose of network management.

- A small fraction of the whole capacity is constituted by the control slots, while a major part is taken by the data slots that carry payload. 

- With the number of control slots, the signaling overhead in DTM varies though it is usually very low.

- Whenever a communication channel is established, a portion of the available data slots is allocated to the channel by the node. 

- There has been an increasing demand of the network transfer capacity because of the globalization of the network traffic and integrated audio, video and data transmission. 

- Optical fibers’ transmission capacity is increasing by great margins when compared to any other processing power. 

- DTM still holds the promise for providing full control to the network resources.