Novel traffic management schemes of a telecommunications network using the concept of virtual links is disclosed. As an example, if a switch connects via a high bandwidth link to an access mux that drives lower bandwidth links. The mux is a potential congestion point in the downstream direction (from high to low bandwidth links) because traffic can arrive at a greater rate over the high bandwidth link than it can exit through the lower bandwidth link. If all of the traffic destined for a particular low bandwidth link can be organized into a unique virtual link. This virtual link can be scheduled at a maximum rate not exceeding the bandwidth of the low bandwidth link, thus preventing the mux from ever becoming a congestion point. Therefore, the amount of mux buffering can be reduced to a very small amount (for jitter absorption). One advantage of this scheme in this example is potentially large cost reductions in the high volume access mux at the lesser expense of a more complex low volume switch.

A data transmission apparatus in which the bandwidth necessary for an application is determined and is communicated to a transmission interval counting function. The transmission interval counting function determines a transmission interval according to the necessary bandwidth and effects transmit control on a transmission unit transmitting function with timing set at this transmission interval so as to transfer data in a desired bandwidth. Owing to the above construction, even when a plurality of types of applications for transmitting data at desired times exist and they perform data transmissions while sharing the use of a network, the contention between the data transmissions in the network can be prevented from occurring. This prevents data losses and delays in data transmission from increasing.

A cell loss priority control method for an ATM switch in which degradation of the traffic characteristics of a high priority class or a low priority class is detected, a cell loss probability distribution in a buffer is estimated from the cell traffic characteristics, a buffer threshold value is obtained in accordance with the estimated cell loss probability distribution, and the cell is controlled by using the obtained buffer threshold value which maximizes total traffic throughput of both the high priority class and low priority class.

Because it is difficult to provide adequate quality of service to large-bandwidth calls in integrated-services networks, service providers may allow some customers to book ahead their calls. The present invention provides a scheme resource sharing among book-ahead calls (that announce their call initiation and holding times upon arrival) and non-book-ahead calls (that do not announce their holding times and enter service immediately, if admitted). The basis for this sharing is an admission control algorithm in which admission is allowed if an approximate interrupt probability (computed in real time) is below a threshold. Simulation experiments show that the proposed admission control methodology is superior to alternative schemes that do not allow interruption, such as a strict partitioning of resources.

Disclosed is an adaptive connection admission control method by traffic measurement and estimation, which includes the steps of determining whether a connection is to be accepted or not by using the peak cell rate among the user-declared traffic parameters and the estimation value of the average cell rate of individual connections under service as inputs when a connection set-up request signal is inputted into the system, the step of reducing the number of connections when a connection release request signal is inputted, and the step of calculating the measured value of the average cell rate of all the connections passing through an output link and the estimated value of the average cell rate of individual connections when the measuring interval has ended, to thereby accomplish accurate and smooth connection controls.