The 2016 IEEE RlVF International Conference on Computing & Communication Technologies, Research, Innovation, and Vision for the Future Load Balancing using Multipath Routing In Network Functions Virtualization Tuan-Minh Pham Hanoi National University of Education Hanoi, Vietnam Email: minhpt@hnue.edu.vn Abstract-Network Functions Virtualization (NFV) is a new approach in architectural model of communication networks, where network functions are softwarized and can be deployed dynamically on most different spots in the network, replacing the specialized equipments located at predetermined locations. NFV comes out as an important transformation trend in the recent development of communication networks due to advantages such as the ability to highly customize the network scale and minimize the investment costs. In this research, we analyze and solve the load balancing problem using multipath routing in NFV to optimize network performance and improve responsive ability of a network system based on NFV according to the dynamic changes of user demands. We propose the FAST-RACE algorithm which has ability to give a weight system on the links of the NFV infrastructure in order to equally distribute load among the several shortest paths and minimize the network delay of data flows in the network. The experiment results show that FAST-RACE declines the average delay of data flows about 26% and could support approximately a 14% increase in the number of service demands in comparison to the load balancing solution using hop-count. Specially, the effective performance of FAST- RACE is not subject to a number of service demands and a number of nodes in the NFV infrastructure. Index Terms-NFV; Network Functions Virtualization; Multi- path routing; Load balancing; I. INTRODUCTION Network Functions Virtualization (NFV) is a new approach in architectural model of communication network to optimize the customization ability in network scale, optimize network performance and minimize investment costs when implement- ing to provide new networking services [1]. Hereby, network functions (e.g. Network Address Translation, Deep Packet Inspection, firewall) are softwarized and virtualized instead of the specialized hardware devices (Le. middlexbox). NFV is based on virtualization technologies to enable virtual network function (VNF) which can be deployed dynamically on the NFV infrastructure (NFVI). Besides, NFV uses other network optimization techniques to provide highly customized network services in order to meet the requirements of changes in network services as well as scale and quality of customer network in flexible and rapid manner. Multipath routing is an important element of controlling load traffic on the network. Load balancing or load shar- ing among multiple paths will reduce congestion, optimize throughput and delay of data flows in the network while reducing risks that a damaged transmission line might ruin Linh Manh Pham INRIA Rennes, France Email: manh-linh.pham@inria.fr the entire network service. Research on models and effective algorithms of the load balancing on multipath routing for NFV is a critical issue to achieve solution that optimizes customization ability and network performance based on NFV. Load balancing is to distribute the load on many paths to optimize throughput, delay and increase availability of the network. A widely used load balancing technique is ECMP (Equal-cost Multipath). The principle of ECMP is total traffic going out from one network node will be divided equally over all the shortest paths with the same cost and to the same destination. Many routing protocols like Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS) supports the multipath routing ECMP [2], [3]. Constraints on using the shortest path routing and load sharing equally to the paths with the same cost makes the problem complex and difficult. The problem becomes more complex when considering the basic characteristics of NFV such as the service function chaining (SFC) in NFV. In this paper, we tackle an optimization problem of load balancing for NFV, which takes into account the service func- tion chaining characteristic of NFV, constraints on the NFVI resource, and ECMP routing features. The first contribution of the paper is an analysis and modeling of the load balancing optimization problems using ECMP for NFV. An important contribution of this study is the FAST-RACE algorithm that we propose to provide an effective solution close to the optimal solution, because the problem is NP-hard. The solution provides a weight system for NFVI links. Based on this weight system, traffic will be distributed automatically and equally on several shortest paths and minimize the network delay of data flows in NFV. We have implemented and tested the algorithm in a NFV infrastructure with the variability of size and number of service demands. The experiment result indicates that FAST-RACE helps reduce the average delay of data flows about 26% and could support approximately a 14% increase in the number of service demands in comparison to the load balancing solution using hop-count. Specially, our algorithm performs effectively with a large-scale NFV infrastructure and a high load network. Our solution can be deployed at a network controller under the incorporation of SDN where the forwarding rules can be distributed to the forwarding plane of a network switch by using OpenFlow [4]. 978-1-5090-4134-3/16/$31.00 ©2016 IEEE 85