A method of controlling data transmission in the ATM network which establishes simple modes of a network control for a case in which a plurality of cell loss priority levels are involved within the cells of a single virtual channel. The method includes the steps of declaring the traffic characteristics for either the loss intolerable cells only, or the loss intolerable cells and the loss tolerable cells separately, and carrying out at the network a connection admission control by estimating a cell loss rate on a basis of the declared traffic characteristics, such that the cell loss rate for either the loss intolerable cells only, or the loss intolerable cells and the loss tolerable cells separately in the multiplexed virtual channels is secured by the network on a basis of the estimated cell loss rate.

Method of controlling data transmission in ATM network with cell loss priority level

This invention relates to a method and apparatus for transmitting constant and variable bit rate traffic in a broadband ISDN switch. Data from constant bit rate sources such as television cameras is entered into a group of queues. Each member of the group for queuing data of a different band of bit rates. Data is transmitted from these queues with highest priority from the queue storing data of the highest band of bit rates. If the longest enqueued entity of data in one of the other queues has been enqueued for more than a prespecified period, its priority is increased. Analytic studies have shown that use of three queues for constant bit rate traffic and a fourth queue for variable bit rate traffic allows a high occupancy in the output channels to be maintained with a negligible number of data entities excessively delayed.

Serving constant bit rate traffic in a broadband data switch

Asynchronous transfer mode (ATM) technology is discussed in relation to the requirements of corporate networking. An introduction to ATM switch architecture is presented. The various approaches to ATM switch design that have appeared in previously published literature are reviewed. A discussion is presented of some current issues facing the development of the ATM networks. It is argued that much simpler solutions to many of these issues may be adopted in the context of the corporate network than is permissible for the public broadband network. >

ATM technology for corporate networks

In an asynchronous transfer mode (ATM) network multimedia environment, the bandwidth efficiency can be improved by defining multiple quality of service (QOS) classes and using a traffic control which manages required QOS of each class individually (QOS control). Priority assignment control is presented as a QOS control method in an ATM switching node. To quantitatively evaluate the control performance, the region determined by the offered load of each class where the QOS requirements of all the classes are satisfied is analytically obtained and various combinations of two classes and related control effects are discussed. When required values of cell loss rate and delay time are both different between the classes, the control effect is large; however, when only either of them is different, the effect is relatively small. The control scheme to enlarge the actual admissible offer load region by adaptively changing the priority assignment ratio is presented and its feasibility is confirmed by the simulation. >

Priority assignment control of ATM line buffers with multiple QOS classes

Broadband switching networks are disclosed, which has a plurality of broadband switch nodes and a broadband switch inter-node transmission line for connecting the plurality of broadband switch nodes, information being transmitted by cells, each of which comprises a header and an information field, wherein the broadband switch node comprises a broadband input and output port for inputting and outputting the cells to and from the broadband inter-node transmission line, and a switch for separating the cells being input through the broadband input and output port and for multiplexing the cells so as to output them, wherein data composed of the plurality of cells is transmitted and received through the broadband switch node by constant bit rate transmission, variable bit rate transmission, or a combination of the constant bit rate transmission and the variable bit rate transmission.

Broadband switching networks

An ATM switching system architecture is presented which employs distributed control to cope with diversified requirements. ATM switching system is expected to efficiently and flexibly handle multimedia traffic, therefore traffic control architecture is one of the most crucial issues for ATM switching systems. The requirements, architectural concept and construction scheme of two important technologies, self-routing switches and quality control of statistical switching, are discussed. A switch fabric, which provides a unified inter-module inter face, switches and distributes cells between modules. It gives very stable switching performance under an arbitrary flow environment without centralized resource management. A three-layerd traffic control model is also presented which consists of cell transfer level, call control level and network control level. Control functions of each level and the interfaces among them are considered, then cell transfer level control schemes and their performances are discussed, including marking scheme for policing control and the effect of burstiness. Laboratory experiment system is designed and implemented to confirm the feasibility of the ATM switching system architecture concept. The system employs a VLSI memory switch with dynamic link speed control as an element of the self-routing switch fabric, achieving the capacity of 256 I55Mb/s lines. It also realizes efficient statistical switching functions such as policing control, multiplexing and quality control for multiple transport quality classes.

S. Hino

Papers

An atm switching system based on a distributed control architecture