07-02-2013, 11:30 AM
A Seminar Report On Dynamic Synchronous Transfer Mode
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ABSTRACT
DTM is a form of circuit switching for fiber-optic networks that employs TDM (time division multiplexing) in a new way that dynamically reallocates available bandwidth to users that need it. DTM was designed to remove the bottleneck at fiber network access points. These bottlenecks are typically caused by the need to process and buffer large amounts packet-based data. DTM seeks to limit complexity and use transmission capacity more efficiently. In particular, DTM can fully support high-bit-rate, real-time traffic, and multicasting. When used as a link layer for IP networks, it can support strict QoS. Along with Gigabit Ethernet and Cisco DPT (Dynamic Packet Transport), DTM is considered one of the technologies to use in new fiber-access metropolitan area networks. Circuit switching has always been more reliable than packe switching, and provides a nonblocking data transmission system (it's predictable because you get all the bandwidth you paid for). At the same time, packet switching has many benefits, including the ability to use bandwidth efficiently by multiplexing the transmissions of many users over mesh-topology links.
DEFINITION AND OVERVIEW
DEFINITION
Dynamic synchronous transfer mode (DTM) is an exciting networking technology. The idea behind it is to provide high-speed networking with top-quality transmissions and the ability to adapt the bandwidth to traffic variations quickly. DTM is designed to be used in integrated service networks for both distribution and one-to-one communication. It can be used directly for application-to-application communication or as a carrier for higher-layer protocols such as Internet protocol (IP). DTM, Dynamic synchronous Transfer Mode, is a broadband network architecture based on circuit switching augmented with dynamic reallocation of time slots. DTM provides a service based on multicast, multi rate channels with short set-up delay. DTM supports applications with real-time QoS requirements as well as applications characterized by bursty, asynchronous traffic
OVERVIEW
This tutorial explores the development of DTM in light of the demand for network-transfer capacity. DTM combines the two basic technologies used to build high-capacity networks—circuit and packet switching—and therefore offers many advantages. It also provides several service-access solutions to city networks, enterprises ,residential and small offices, content providers, video production networks, and mobile network operators.
PACKET-SWITCHED NETWORKS
Packet switching was developed to cope more effectively with the data-transmission limitations of the circuit-switched networks during bursts of random traffic. In packet switching, a data stream is divided into standardized packets. Each contains address, size, sequence, and error-checking information, in addition to the payload data. The packets are then sent through the network, where specific packet switches or routers sort and direct each single packet.
SLOT ALLOCATION
DTM uses a distributed algorithm for slot reallocation, where the pool of free slots is distributed among the nodes. At the reception of a user request, the node first checks its own time slots to see if it has slots enough to satisfy the request and, if so, immediately sends achannel establishment message to the next hop. Otherwise, the nodefirst has to request more slots from the other nodes on the link. Each node maintains a status table that contains information about free slots in other nodes, and when more slots are needed the node consults its status table to decide which node to ask for slots. Every node regularly sends out status messages with information about its local pool of slots.
CHANNEL ESTABLISHMENT
Each node has a network controller, which handles the node-tonode signaling. This signaling is done via the control slots and is used for channel management and time slots reservation. When a DTM user wants to set up a channel, it sends a create primitive to the network control element which allocates the necessary bandwidth and sends an announce message to the receiving node. The network control element also sets up the channel tables in the DTM link layer and sends back an indication primitive, notifying the sending user that the requested capacity, i.e. the requested number of slots per frame, have been allocated. The user either waits for a confirmation from the receiving side (video, voice) or sends data directly after receiving the indication (datagram).
CONCLUSION
DTM has been developed and tested since 1990 in a research environment. The basic principles are well tested, and the product development has been preceded by several generations of research pilots. The necessary protocols are well developed and ready for standardization. Working beta systems exist. Within ETSI the standardization of the Dynamic synchronous Transfer Mode (DTM) technology is underway. There are several patents and patentapplications related DTM.
[attachment=49974]
ABSTRACT
DTM is a form of circuit switching for fiber-optic networks that employs TDM (time division multiplexing) in a new way that dynamically reallocates available bandwidth to users that need it. DTM was designed to remove the bottleneck at fiber network access points. These bottlenecks are typically caused by the need to process and buffer large amounts packet-based data. DTM seeks to limit complexity and use transmission capacity more efficiently. In particular, DTM can fully support high-bit-rate, real-time traffic, and multicasting. When used as a link layer for IP networks, it can support strict QoS. Along with Gigabit Ethernet and Cisco DPT (Dynamic Packet Transport), DTM is considered one of the technologies to use in new fiber-access metropolitan area networks. Circuit switching has always been more reliable than packe switching, and provides a nonblocking data transmission system (it's predictable because you get all the bandwidth you paid for). At the same time, packet switching has many benefits, including the ability to use bandwidth efficiently by multiplexing the transmissions of many users over mesh-topology links.
DEFINITION AND OVERVIEW
DEFINITION
Dynamic synchronous transfer mode (DTM) is an exciting networking technology. The idea behind it is to provide high-speed networking with top-quality transmissions and the ability to adapt the bandwidth to traffic variations quickly. DTM is designed to be used in integrated service networks for both distribution and one-to-one communication. It can be used directly for application-to-application communication or as a carrier for higher-layer protocols such as Internet protocol (IP). DTM, Dynamic synchronous Transfer Mode, is a broadband network architecture based on circuit switching augmented with dynamic reallocation of time slots. DTM provides a service based on multicast, multi rate channels with short set-up delay. DTM supports applications with real-time QoS requirements as well as applications characterized by bursty, asynchronous traffic
OVERVIEW
This tutorial explores the development of DTM in light of the demand for network-transfer capacity. DTM combines the two basic technologies used to build high-capacity networks—circuit and packet switching—and therefore offers many advantages. It also provides several service-access solutions to city networks, enterprises ,residential and small offices, content providers, video production networks, and mobile network operators.
PACKET-SWITCHED NETWORKS
Packet switching was developed to cope more effectively with the data-transmission limitations of the circuit-switched networks during bursts of random traffic. In packet switching, a data stream is divided into standardized packets. Each contains address, size, sequence, and error-checking information, in addition to the payload data. The packets are then sent through the network, where specific packet switches or routers sort and direct each single packet.
SLOT ALLOCATION
DTM uses a distributed algorithm for slot reallocation, where the pool of free slots is distributed among the nodes. At the reception of a user request, the node first checks its own time slots to see if it has slots enough to satisfy the request and, if so, immediately sends achannel establishment message to the next hop. Otherwise, the nodefirst has to request more slots from the other nodes on the link. Each node maintains a status table that contains information about free slots in other nodes, and when more slots are needed the node consults its status table to decide which node to ask for slots. Every node regularly sends out status messages with information about its local pool of slots.
CHANNEL ESTABLISHMENT
Each node has a network controller, which handles the node-tonode signaling. This signaling is done via the control slots and is used for channel management and time slots reservation. When a DTM user wants to set up a channel, it sends a create primitive to the network control element which allocates the necessary bandwidth and sends an announce message to the receiving node. The network control element also sets up the channel tables in the DTM link layer and sends back an indication primitive, notifying the sending user that the requested capacity, i.e. the requested number of slots per frame, have been allocated. The user either waits for a confirmation from the receiving side (video, voice) or sends data directly after receiving the indication (datagram).
CONCLUSION
DTM has been developed and tested since 1990 in a research environment. The basic principles are well tested, and the product development has been preceded by several generations of research pilots. The necessary protocols are well developed and ready for standardization. Working beta systems exist. Within ETSI the standardization of the Dynamic synchronous Transfer Mode (DTM) technology is underway. There are several patents and patentapplications related DTM.