Delay Performance of Resilient Cloud Services over Networks

Even though both delay and availability are of high importance for cloud services, it is mostly impossible today to guarantee a certain latency and availability for end-to-end cloud services traversing the telecommunication networks. An enabler is network virtualization with isolated virtual networks and combined control for network and IT resources. In this paper, we introduce two fundamental architectural alternatives in resilience design for cloud services using virtual networks, where in the former, resilience is provided solely by the physical infrastructure provider and in the latter only by the virtual network operator. We show that the resilience design plays a key role in terms of latency of the cloud services. Our simulation results show that the guaranteed maximum delay for the cloud services can differ by more than 90% depending on the implemented resilience design. This can have a big impact on the service performance in large networks especially for today's applications, where each millisecond might count.