Growable packet switch with two priority classes

Growable packet switch (GPS) is known to be able to construct arbitrarily large switches out of modest-size packet switches. However, the conventional GPS deals with only one kind of traffic. In this paper, we propose two methods that make the GPS enable to support two kinds of traffics with different requirements by using three principles, such as 1) middle module for the exclusive use of each class, 2) higher priority at each output buffers for the class 1 packets which require small waiting time, 3) buffering of class 2 packets which require small packet loss probability. An approximate analysis for packet loss probability and mean waiting time of each class is performed by numerical calculations and simulations. It is shown that mean waiting time of class 1 packets is much less than that of class 2 packets and loss probability of class 1 packet is low.