TVM: Tabular VM migration for reducing hop violations of service chains in cloud datacenters
Network Function Virtualization is a recent and significant development applied in cloud datacenters, which can help service providers manage network services more flexibly and economically than using middle-boxes. User requests may demand different numbers of services in a chain, where the related flows can be directed to different physical machines (PMs) hosting required virtual network functions (VNFs) in a designated order. Sometimes, with the limited resources in current PMs, the deployment of service chains may result in great hop counts and cause hop (latency) violations against the service level agreements (SLAs) of user requests. Therefore, we propose a dynamic service-chain management approach called Tabular VM Migration (TVM) to reduce hop violations of service chains in cloud datacenters. Different from other VM management policies, TVM considers the order of a set of VMs in a service chain and migrates key VMs which may cause hop violations onto the selected PMs. Thus, hop violations are reduced with few migrations. Simulation results indicate that TVM performs better than other common VM management policies, and reduce at most 16.68% of total number of hop violations induced by a static deployment approach (SOVWin).