Performability analysis of services in a software-defined networking adopting time-based moving target defense mechanisms.

Moving target defense (MTD) has been developed as an emerging technology to enhance system/network security by randomly and continuously changing attack surface. Despite the significant progress of recent efforts in analyzing the security effectiveness of MTD mechanisms, critical gaps still exist in terms of the impact of running MTD mechanisms on system performance and dependability, exposing a critical design tradeoff between security and performance. To investigate the tradeoff, we propose performability models for evaluating services hosted in software-defined networks with a time-based MTD mechanism being deployed. We developed analytical models for evaluating key performability metrics, in terms of response time, throughput, availability, host utilization, a number of requests lost, and cost (i.e., energy consumption plus profits lost due to dropped jobs). Our results showed that using the time-based MTD mechanism can (1) improve service response time and host utilization; (2) introduce a higher number of requests lost and higher overall cost; and (3) reduce service availability while still handling most of the jobs without much performance degradation.