China Communications • October 2017 1 large number of manual configuration and it’s difficult to integrate networking devices from different suppliers. However, SDN [1] can of- fer a more flexible and convenient way for the fine-grained TE which is flow-based forward- ing different from the TE in conventional IP networks which is the destination-based for- warding [2], [3]. Besides, the SDN can simpli- fy network operations and accelerate service delivery by open standardized interfaces and centralized control. What’s more important is that the migration from the legacy networks to the SDNs can also bring benefits to the customers. Openness which is one of main properties of the SDN can provide customers choice to build the best-of-breed networks. More forwarding paths available to carry the flows from the customers under the control of the central controller can provide more op- portunities to establish the demand services specified by the customers and reduce the end- to-end delay, therefore to improve the Quality of Experience (QoE) of the customers. The general traditional network migra - tion is a technical process of upgrading and exchanging the existing hardware/software (infrastructure) to other traditional network devices [4], [5], [6]. In the SDN scenarios, for- warding devices can select not only the port or ports of the shortest paths but also other ports to route flows for one source-destination pair. Abstract: Software Defined Networking (SDN) provides a flexible and convenient way to support fine-grained traffic-engineer- ing (TE). Besides, SDN also provides better Quality of Experience (QoE) for customers. However, the policy of the evolution from legacy networks to the SDNs overemphasizes the controllability of the network or TE while ignoring the customers’ benefit. Standing in the customers’ position, we propose an opti- mization scheme, named as Optimal Migra- tion Schedule based on Customers’ Benefit (OMSB), to produce an optimized migration schedule and maximize the benefit of custom- ers. Not only the quality and quantity of paths availed by migration, but also the number of flows from the customers that can use these multi-paths are taken into consideration for the scheduling. We compare the OMSB with other six migration schemes in terms of the benefit of customers. Our results suggest that the sequence of the migration plays a vital role for customers, especially in the early stages of the network migration to the SDN. Keywords: network management; network migration; software-defined networking; traf- fic engineering I. INTRODUCTION TE in the legacy networks usually needs a Migration to Software-Defined Networks: the Customers’ View Tingting Yuan 1 , Xiaohong Huang 1, *, Maode Ma 2 , Pei Zhang 1 1 Institute of Network Technology, Beijing University of Posts and Telecommunications 2 School of Electrical & Electronic Engineering, Nanyang Technological University * The corresponding author, email: huangxh@bupt.edu.cn Received: Apr. 20, 2017 Revised: Aug. 7, 2017 Editor: Gaogang Xie FUTURE INTERNET ARCHITECTURE AND TESTBEDS