Virtualized server infrastructure for resilient voice communication service

The huge earthquake struck Japan on 11th March, 2011, caused a massive congestion of call attempts from mobile phones that resulted in only 5% of accepted connections due to the congestion control by telephone companies. It is an emergent issue to improve resiliency of communication service in anticipation of future disasters and thus communication service infrastructure necessitates the flexibility of its capacity. In this paper, we introduce server virtualization technology to provide a flexible communication service infrastructure and design a communication service controller that provisions additional capacity by virtual machines in response to increased call attempts from mobile phones after a disaster. The communication service controller is designed with constraint programming and performance/availability estimations for deciding the optimum virtual machine placement according to network operator´s instructions. Through an experimental disaster test, we confirm the capacity of communication service is increased five-fold by virtual machine provisioning with half an hour latency.