A Markov model of CCN pending interest table occupancy with interest timeout and retries

Abstract

The occupancy of the pending interest table (PIT) in content-centric networks (CCN) and other information-centric networking (ICN) architectures has an undeniable effect on the congestion level and the performance of the network. Each interest packet forwarded upstream by a node results in at most one data packet arriving back at the node and being possibly forwarded to many interfaces downstream. Clearly, to regulate the rate of arrival of new data chunks at a node, one can regulate the arrival rate of interest packets. To be able to design effective mechanisms to control the traffic in CCN, a systematic study and analysis of the PIT occupancy is thus imperative. In this paper, we derive an analytical model to estimate the PIT occupancy distribution via an approximate continuous time Markov (CTMC) model and validate the model via simulation experiments with different system parameters. Our proposed model is not only useful in the design of traffic controllers for managing the PIT occupancy but also offers an effective method for dimensioning the PIT.