Delay and capacity analysis of structured P2P overlay for IP telephony

In this paper, we provide an analytical model for the structured P2P overlay based on Chord DHT used for lookup service in session based applications like IP telephony systems. Our model captures the performance behavior of such overlays including the mean session set-up delay of a call as well as the system capacity. These parameters reflect how good the overlay as a lookup service is performing. We formulate the system as a queuing network. We idealize Chord routing semantics to extract useful characteristics to obtain closed form expressions for the session setup delay and capacity as a function of the number of participating supernodes. The analysis also answers the question of finding an optimum number of supernodes for minimum session setup delay.