This paper presents a methodology to calculate the worst-case reliability of smart distribution system. Impact of communication infrastructure failure on the system reliability is investigated in both substation-centered and decentralized multi-agent restoration management. Different communication infrastructure is also examined to evaluate the impact in the reliability of the substation centered distribution system. Comparison of the Worst-case Expected Energy Not Served (WEENS) is performed for all scenarios. Worst case communication link failure is adopted in reliability evaluation of cyber enabled distribution system.