Efficient Load Balancing for the VNF Deployment with Placement Constraints

Abstract

The Virtual Network Function (VNF) deployment problem in Network Function Virtualization (NFV) is of broad theoretical and practical interests. As the traffic surges in data centers, VNF deployment requires load balancing across the servers to avoid possible congestions caused by the uneven distribution of VNFs. In addition, VNFs always specify placement constraints, restricting them to run only on part of the servers. Therefore, we study the load balancing problem for VNF deployment with placement constraints. Despite the rich bodies of recent work on the constrained load balancing problem using the network flow algorithms, they all suffer exponential complexities, leading to unbearable running time in practical executions. In this paper, we propose a new load balancing policy termed Constrained Min-max Placement (CMMP) that schedules VNFs in a way similar to the max-min allocation, where we try to assign the most possible VNFs to the poorest loaded server. The online scheduler for CMMP has a logarithmic time complexity and is simple enough to implement in practice. Trace-driven simulations show that the online CMMP speeds up at least two orders of magnitude of running time comparing to other network flow algorithms.