  Given the rapid increase in traffic, greater demands have been put on
research in high-speed switching systems. Such systems have to simultaneously
meet several constraints, e.g., high throughput, low delay and low complexity.
This makes it challenging to design an efficient scheduling algorithm, and has
consequently drawn considerable research interest. However, previous results
either cannot provide a 100% throughput guarantee without a speedup, or require
a complex centralized scheduler. In this paper, we design a distributed 100%
throughput algorithm for crosspoint buffered switches, called DISQUO, with very
limited message passing. We prove that DISQUO can achieve 100% throughput for
any admissible Bernoulli traffic, with a low time complexity of O(1) per port
and a few bits message exchanging in every time slot. To the best of our
knowledge, it is the first distributed algorithm that can provide a 100%
throughput for a crosspoint buffered switch.
