Rafael Gidron

MAGNET II: a metropolitan area network based on asynchronous time sharing

MAGNET II is a testbed for integrated networks. It was designed and implemented based on requirements of real-time network management and control. Quality-of-service requirements explicitly appear in the design specifications of the network on the media access level. Switching is based on the concept of asynchronous time sharing. The core of the network distinguishes between three traffic classes. The quality of service of these classes is monitored and controlled by the traffic-control architecture of the network. Monitoring is supported by observation units distributed throughout the system. The main network resources, switching bandwidth, communication bandwidth, and buffer space, are observable and controllable. >

TeraNet: a multi-gigabits per second ATM network

Abstract TeraNet is an experimental network being built at the Center for Telecommunications Research, Columbia University. The network is part of the ACORN (Advanced Communications Organization for Research Network) project. The purpose of ACORN is to investigate innovative optical network architectures which offer user access at data rates as high as one Gigabit per second (Gbit/s). The design principles of TeraNet incorporate three main concepts: a transmission medium that contains multiple channels; a system architecture that employs a multihop approach to routing packets; and a traffic control architecture that supports multiple traffic classes. The network contains a set of network interface units (NIU) that are interconnected with passive optics. Each NIU is a two-by-two switch with an additional user access port. Each of the six NIU ports (three input and three output) can handle data rates up to one Gbit/s. The NIU buffers and the bandwidth of the output links are shared by four traffic classes according to the ATS concept of resource allocation. The packet format and routing procedure are compatible with the emerging ATM standard.

TeraNet: a multihop multichannel ATM lightwave network

TeraNet is an experimental network which offers user access rates as high as one gigabit per second. The design principles of TeraNet incorporate three main concepts: a transmission medium that contains multiple channels, a system architecture that employs a multihop approach to routing packets, and a traffic control architecture that supports multiple traffic classes. The network contains a set of network interface units (NIUs) that are interconnected with passive optics. Each NIU is a two by two switch with an additional input and output port for user access. Output buffers and the bandwidth of the output links are shared according to a resource allocation concept called asynchronous time sharing (ATS). The packet format and routing procedure are compatible with the emerging asynchronous transfer mode (ATM) standard.<<ETX>>

A switching architecture for asynchronous time sharing

The concept of asynchronous time sharing is based on a multiclass network model and a distributed scheduling algorithm that provides guaranteed quality of service. There are three traffic classes for transporting user information and a fourth class for network management and control. Access to resources is resolved through a scheduling mechanism based on time sharing and space partitioning. A generic switching architecture that supports asynchronous time sharing and guarantees quality of service as negotiated at call setup is presented. The architecture exhibits switch fabric independence and only requires that the switch fabric be nonblocking. An operating implementation is described in detail.<<ETX>>

A metropolitan area network based on asynchronous time sharing

A metropolitan area network is described that guarantees quality of service on the hardware level. The network supports three classes of traffic. Switching is based on the principle of asynchronous time sharing, i.e., the three traffic classes enter any switch fabric sequentially. The system architecture consists of a set of generic switch fabrics that are implemented as buses, rings, or link schedulers. A switching node typically consists of a ring that interconnects a set of access buses; these nodes are interconnected via T3/DS3 links. A flexible hardware design that supports the traffic control architecture in order to guarantee the quality of service as negotiated at call setup is also presented.<<ETX>>

Project ACORN and distributed approaches to ATM networks

Centralized and distributed approaches to the design and implementation of a multi-gigabit per second asynchronous transfer mode (ATM) switch are discussed. The implementation constraints associated with a centralized switch are demonstrated and an alternative distributed optical network architecture is described. The distributed approach exploits unique opportunities presented through the use of a passive optical medium. A network based on these principles (TeraNet), has been implemented that offers user access rates of 1 Gbit/s. The distributed ATM switch fabric resides in small, geographically dispersed access stations interconnected by a shared, all-optical medium carrying many wavelength-multiplexed channels. Although the underlying multihop architecture for the ATM network produces a lower per-port throughput than that afforded by a large centralized ATM switch, significant implementation advantages exist. Possible techniques to yield a higher per-port throughput approaching that of a large centralized switch are also discussed.<<ETX>>

A User Tunable Access Lightwave Network

A new approach to reconfiguration management of a wavelength-multiplexed multihop lightwave network is proposed. Unlike earlier approaches, this «User Tunable Access Lightwave Network» employs a fixed connection diagram among the multihop access stations but allows each user to select its «home» access station by means of a wavelength agile optical transmitter, capable of retuning on a time scale comparable with the setup time of a new virtual connection. By so doing, it becomes possible to effect a reconfiguration with minimal impact upon existing virtual connections. A traffic-driven heuristic is presented which can rapidly adapt to time-varying traffic patterns and which can be implemented on a distributed basis within the multihop access stations, with each station requiring knowledge of only its own generated traffic

Designing an IMAC system using TeraNet

Even though considerable progresses have been made with communication technology, one of the more difficult problems facing in installing a comprehensive clinically effective Image Management and Communication (IMAC) system for a hospital is the communication problem. Most existing systems are based on Ethernet or Token-ring net. Some of the newer systems are being installed using FDDL. All these systems have inherent problems like communication speed, control of bandwidth usage, or/and poor performance under heavy traffic. In order to overcome these difficulties, we are designing a complete IMAC system based on a novel network known as TeraNet, being developed at Center for Telecommunication Research, Columbia University.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Design and implementation of a distributed switching node for a multihop ATM network

Design and implementation issues for large distributed asynchronous transfer mode (ATM) switching systems are considered. The ATM switch fabric resides in small, geographically dispersed access stations interconnected by a shared, all-optical medium carrying many wavelength-multiplexed channels. The authors present the architecture of the distributed ATM fabric and describe the optical subsystem. They summarize the per-port throughput relative to the dimensionality of the distributed switching elements contained in the access station, and discuss design considerations relative to the dimensionality of the switching element. The detailed design of an access station, or network interface unit (NIU), and its associated subsystems, implemented as part of the ACORN/TeraNet project, are presented.<<ETX>>