Optimizing NFV Chain Deployment through Minimizing the Cost of Virtual Switching

Network Function Virtualization (NFV) is a novel paradigm that enables flexible and scalable implementation of network services on cloud infrastructure. A key factor in the success of NFV is the ability to dynamically allocate physical resources according to the demand. This is particularly important when dealing with the data plane since additional resources are required in order to support the virtual switching of the packets between the Virtual Network Functions (VNFs). The exact amount of these resources depends on the way service chains are deployed and the amount of network traffic being handled. Thus, orchestrating service chains that require high traffic throughput is a very complex task and most existing solutions either concentrate on handcrafted tuning of the servers to achieve the needed performance level, or present theoretical placement functions that assume that the switching cost is part of the input. In this work, we bridge this gap by presenting a deployment algorithm for service chains that optimizes performance by minimizing the actual cost of virtual switching. The results are based on extensive measurements of the actual switching cost and the performance of service chains in a realistic NFV environment. Our evaluation indicates that this new algorithm significantly reduces virtual switching resource utilization when compared to the de-facto standard placement in OpenStack/Nova - allowing a much higher acceptance ratio of network services.