Priority mechanisms in ATM networks

Cell loss priority mechanisms for the asynchronous transfer mode (ATM) are discussed. The introduction of loss priority mechanisms implies an increase of the maximum admissible load, on ATM pipes or a decrease of the necessary size of the buffers in ATM switches. The gain achieved by loss priorities is calculated for the example of an ATM switch with a shared buffer. Using a mathematical analysis, it is shown that loss priorities increase the admissible load of the ATM pipes slightly in the case of a Poisson arrival process. About 15-20% of the buffer places can be saved, even for unfavorable traffic mixes (for maximum admissible cell loss probabilities of 10^-10 for high-priority cells and 10^-5 for low-priority cells)