On the infinite buffer model and the implementation aspects of the pi-persistent protocol for unidirectional broadcast bus networks

The p_i-persistent protocol is proposed for packet switched multiaccess communication over unidirectional broadcast bus networks. The author´s concern is to further develop this protocol in order to make it easily implementable by allowing it to be sensitive to fluctuations in the offered traffic. In so doing, a study is made of the infinite buffer model of this protocol. The conditions for channel stability are obtained. Three criteria for fairness are studied, and corresponding to each, the author obtains the set of proper p _i that achieves the given fairness criterion. The protocol is applied to an example network, and its performance is compared with that of an equivalent round-robin protocol. It is found that even with infinite buffers, this protocol achieves a capacity of unity, provides better delay vs. throughput behavior than round-robin schemes, and it is insensitive to the bus length and data rate. Performance under some improper p_i is studied, showing that the difference in network performance is not very significant compared to that under proper p_i