Performance Modeling of SDN with NFV under or aside the Controller Ahmed Fahmin 1 , Yuan-Cheng Lai 2 , Md. Shohrab Hossain 1 , Ying-Dar Lin 3 , and Dipon Saha 1 1 Department of Computer Science and Engineering, Bangladesh University of Engineering and Technology, Bangladesh 2 Department of Information Management, National Taiwan University of Science and Technology, Taipei, Taiwan 3 Department of Computer Science, National Chiao Tung University, Hsinchu, Taiwan Email:ahmedfahmin@gmail.com, laiyc@cs.ntust.edu.tw, mshohrabhossain@cse.buet.ac.bd, ydlin@cs.nctu.edu.tw, dipon2276@gmail.com Abstract—Software Defined Networking (SDN) emphasizes the separation of data and control plane while network function virtualization (NFV) decouples network function from underlying hardware. Combining SDN with NFV would have many benefits, but the problem is how to integrate them. There are two possible architectures for such integration: the controller interacts with virtualized network functions (VNFs) or the switch interacts with VNFs. In this paper, the former is referred to as NFV under the controller (NFV C) while the latter is called NFV aside the controller (NFV AC). To the best of our knowledge, there is no analytical model for mathematically investigating the performance of such architectures. This paper therefore aims to carry out analytical modeling of SDN with NFV under or aside the controller. We model and analyze these two SDN+NFV architectures using M/M/1 queuing model and validate our analysis with various simulations. Results show that the analytical results well match the simulation results. Also a packet delay reduction of 54.67% can be achieved for NFV AC over NFV C, meaning that NFV AC is a better architecture for integrating SDN with NFV. Index Terms—SDN, Network function virtualization, M/M/1 queuing model, OpenFlow. I. I NTRODUCTION Traditionally, a network is built on dedicated hardware, such as routers and switches, with network software provided by the network vendors. A network engineer’s ability to customize the network software is very limited and is mostly restricted by the network vendor. This has led to the concept of Software Defined Networking (SDN), where flexibility and dynamism have been introduced in the virtualization of the control plane. The basic approach is to separate a network into a control plane and a data plane, thereby being able to manage various network devices centrally. The main benefit of the SDN concept is the programability of controlling the network devices. This has enabled network engineers to change network configuration and the logic of data flow according to the business requirements. On the other hand, Network Function Virtualization (NFV) is a new approach which deploys or designs various network functions. It decou- ples the network functions, such as NAT, DNS caching, etc. from their proprietary hardware appliances, so that they can be implemented in virtual machines, improving their service quality. SDN focuses on the separation of the network control plane from the physical routers’ data plane. SDN is treated as the control software that sits atop a bunch of physical devices with which it communicates through interfaces. On the other hand, NFV is about virtualizing various resources into network functions in software, so that we do not need any specialized physical devices dedicated to any particular network functions. Recent works [1], [2] have shown that both SDN and NFV can be combined to provide more centralized control software and generic hardware where the utilities of SDN can be realized through virtualized robust network functions provided by NFV. There are several works [3]–[10] on SDN modeling. None of these has considered NFV in their analytical modeling. Two recent works [1], [2] have investigated the performance of SDN and NFV coexisting architecture using simulation and experimentation. However, no analytical model was developed for the SDN architecture combining with NFV. This work is the first to model the architecture that combines SDN with NFV, as well as analyzing its performance. There are different approaches to combining SDN with NFV. Since the controller determines which instance of vir- tualized network function (VNF) serves the packets which need network functions (NFV packets for short), the NFV packets can be redirected to the controller from the switch. The controller then forwards these NFV packets to the proper VNF for executing the required network functions. That is, the NFV packets will pass through the controller. This approach is called SDN with NFV under the controller (NFV C). Another approach is that some of the NFV packets are sent to the controller, the controller determines which instance of VNF will serve these packets, and will set in motion the appropriate actions for the switch. Consequent NFV packets belonging to the same flow can be directly redirected to the determined instance of VNF without the controller. We term this approach SDN with NFV aside the controller (NFV AC). The main objective of this work is to carry about analytical modeling of NFV C and NFV AC. We also demonstrate a comparison between the two architectures based on the delay of NFV packets. Our work covers: (i) developing the analytical models for the two architectures, (ii) performing simulation to validate our analytical model, and (iii) performing sensitivity analysis of certain system parameters (such as arrival rates, 2017 5th International Conference on Future Internet of Things and Cloud Workshops 978-1-5386-3281-9/17 $31.00 © 2017 IEEE DOI 10.1109/W-FiCloud.2017.15 211 2017 5th International Conference on Future Internet of Things and Cloud Workshops 978-1-5386-3281-9/17 $31.00 © 2017 IEEE DOI 10.1109/FiCloudW.2017.76 211