ENSC: Multi-Resource Hybrid Scaling for Elastic Network Service Chain in Clouds

Software-based network service chains in Network Function Virtualization (NFV) need to be dynamically allocated and scaled on hardware resources. This is because the resource demand of virtual network functions (VNFs) typically varies as a results of network flow volume. NFV elastic solutions by coarse-grained horizontal scaling or fine-grained vertical scaling have been investigated in recent years. However, none of the existing solutions can achieve both efficiency and scalability. To address this challenge, we propose elastic network service chain (ENSC), which utilizes a fine-grained hybrid scaling method to achieve both NFV efficiency and scalability. We systematically compare horizontal scaling with vertical scaling from six aspects and determine the priority within hybrid scaling. We formulate the resource allocation problem in the cloud datacenter as an integer linear programming (ILP) model and develop a heuristic algorithm called Rubik. Our evaluation results show that ENSC achieves higher acceptance ratios and resource utilization than horizontal scaling and vertical scaling methods.