SDN/NFV Enhanced Time Synchronization in Packet Networks

The need for distribution of accurate and reliable time synchronization is more and more urgent, especially with the development of the fifth-generation (5G) network and the rise of high precision communication. However, the vast majority of the current packet networks is the best effort and cannot offer precision time synchronization. To enable the precise time feature in packet networks, a novel time synchronization scheme is proposed based on software-defined networking/network functions virtualization enabled network architecture, exploring the programmability of network time synchronization as a fundamental concept to define the function model for core components. Time synchronization is built as a virtual network function (VNF), and a synchronization controller is designed to manage the synchronization processing and precision compensation together with the network controller and the proposed VNF. More specifically, the time synchronization model and compensation algorithms are introduced to reveal the mechanism of the synchronization process. To thoroughly study the performance of the proposed scheme, an analytical model is developed that covers the primary influencing factors of synchronization accuracy, including the link length, delay coefficient, timestamping granularity, and local oscillator's characteristic of the network element. Further, experimental and analytical results are presented to demonstrate the effectiveness of the proposed scheme.