Asynchronous Transfer Mode Networking Research Articles

Virtual path group protection switching-A method for fast ATM network survivability

A telecommunications network often has survivability capabilities to restore service following the occurrence of various service-affecting defects. To ensure high reliability over a wide range of services, the network must be able to restore service very quickly, on the order of 60 to 200 ms. This requirement can place extreme and costly processing demands on network elements (NEs). Many different survivability techniques are possible depending on an application's cost, service, and performance requirements. Furthermore, networks are now being developed based on asynchronous transfer mode (ATM) technology and carried within a synchronous digital hierarchy/synchronous optical network (SDH/SONET) physical layer. In these networks, the existing physical-layer protection switching capabilities (for example, SDH/SONET line or path protection switching) cannot detect ATM-specific defects (such as loss of ATM connection continuity) and thus cannot protect against them. While protection switching of individual ATM virtual connections (virtual path [VP] or virtual channel [VC]) could be added to accommodate ATM-specific defects, such a large-scale defect as a facility failure will cause a fault on each of hundreds or even thousands of separate ATM connections and thus will require as many simultaneous and independent restoration operations. The virtual path group (VPG) protection switching technique described in this paper offers both fast restoration (on the order of 60 ms) and minimum processing. This technique, useful in a broad range of ATM networking applications, provides high-performance network protection largely consistent with established ATM standards. It forms a basis for emerging ATM network protection standards, and it will provide leading-edge network survivability features to future Lucent Technologies ATM solutions.

Real-time transmission of multilayer video over ATM networks

With today's network technology, our expectations for high performance networked multimedia applications are increasing. However, no complete solution as yet exists for providing integrated services to networked multimedia systems. The difficulty lies in the nature of the multimedia data, basically video and audio, which is difficult to store and transmit. The coded video is sensitive to delay, delay variation, bit errors and losses. Our research focuses on the transmission of multilayer real-time video traffic over ATM (Asynchronous Transfer Mode) networks. This issue covers several aspects of ATM and multimedia networking such as video application layer, ATM adaptation layers, traffic and buffer management. The main assumption in this research is that the real-time video traffic is content based coded and consists of several video objects. A single video source with various video objects introduces the need for multiple priorities. We propose a multipriority traffic management model for ATM networks that includes a new priority cell mapping algorithm, a new priority based bandwidth allocation approach, a new adaptation layer definition, and a new multipriority buffer access control algorithm. Using multipriority traffic will complicate the traffic management, the buffer management and the work of the ATM adaptation layers. On the other hand, by allowing the network to have several priority layers during a connection, the overall quality for real-time video will be increased. To our knowledge, no method exists for managing a single connection for multipriority video traffic over ATM networks. Our model is new and addresses the essential transmission requirements of near future multipriority video coding systems over broadband networks.

Engineering ATM networks for congestion avoidance

With the combination of telecommunication, entertainment and computer industries, computer networking is adopting a new method called Asynchronous Transfer Mode (ATM) networking. Congestion control plays an important role in the effective and stable operation of ATM networks. Traffic management concerns with the design of a set of mechanisms which ensure that the network bandwidth, buffer and computational resources are efficiently utilized while meeting the various Quality of Service (QoS) guarantees given to sources as part of a traffic contract. In this paper, the most widely recognized congestion control schemes for ABR service are investigated. Some of these schemes show either lack of scalability or fairness while other well‐behaved schemes may require a highly complex switch algorithm that is unsuitable for implementation in cell‐switching high‐speed ATM networks. A new and improved congestion control scheme is proposed to support the best‐effort ABR traffic. This algorithm provides the congestion avoidance ability with high throughput and low delay, in addition to achieving the max–min fairness allocation.

Airline with the personal touch

Passengers flying with Cathay Pacific from Hong Kong's new Chek Lap Kok Airport may not be in too much of a hurry to board their plane once they see what the airline's high-tech departure lounge has to offer. The major IT element within the lounge is a unique state-of-the-art passenger `infotainment' network that allows passengers to access a multitude of services via custom-built desktop units. The system is based around asynchronous transfer mode (ATM) networking technology, which provides a high-speed switching capability for multimedia sources such as video, graphics, text and audio. Passengers access services via a touch screen by swiping their boarding pass through a built-in boarding pass/credit card reader. This immediately personalises the display according to records stored in a customer database, and the passenger is presented with a customised graphical user interface that allows them to navigate through a number of different menu levels with four simple, colour coded `hot' buttons: forward, backward, main menu and restart. At a touch they can find flight information, choose from a large number of TV channels, obtain the latest share price information, view travel facts about their destination, or perhaps listen to a selection of radio channels. Looped video material similar to traditional in-flight entertainment is also provided.

Neuro-fuzzy control in ATM networks

The aynchronous transfer mode (ATM) has been deemed the transfer technique of choice in an integrated environment supporting multimedia services. The authors present an extensive review of fuzzy-logic-based and artificial-neural-network-based traffic control mechanisms that have been proposed in the field of asynchronous transfer mode networking. Following a qualitative review of the models used, system architectures suggested and results obtained, future trends and directions are briefly discussed.

A managerial analysis of ATM in facilitating distance education

In this paper, the fundamental characteristics and capabilities of ATM (Asynchronous Transfer Mode) networks in a distance learning environment are examined. Current and projected ATM applications are described. Issues and challenges associated with developing ATM networking solutions for instructional delivery are explored. Guidelines facilitating ATM implementation in the educational setting for instructional enrichment are presented.