Masking compressed video connection utilization in ATM networks

This paper examines the use of cell injection to change the observable characteristics of Variable Bit Rate (VBR) ATM connections most commonly used to transport compressed video. “Cell Injection” is a technique for masking Virtual Connection (VC) utilization in ATM networks from undesired third parties by altering the flow of traffic over the connection. We model the cell injection process as a Markov Modulated Poisson Process (MMPP) and discuss both the theoretical and applied aspects of the cell injection approach. Aggregate bounds for sustained cell rate (SCR) and mean burst size (MBS) are derived using the Cruz bound. Analytic results are compared with measurements of real cell-injected ATM traffic and the effects of injection on the original traffic are summarized. The results demonstrate that VBR characteristics can be effectively masked within reason. Further, an interesting side effect is that cell injection shifts the power in the mid and high frequency regions towards low frequency regions, which is the dominant factor in queue length distributions