Nowadays, many applications need varying levels of Quality of Service (QoS). The network that provides the communication service connects the servers and clients. The network traffic which is routed through the network should be engineered. Traffic Engineering (TE) is a mechanism for transferring the packets considering the different QoS level requirements among applications. The optimal resource allocation is the primary strategy for TE so that the network can provide the QoS requirements for each application. The TE can improve network efficiency, performance, and user satisfaction. Software Defined Network (SDN) has been proposed as the novel network architecture that could make networks agile, manageable, and programmable using control and data plane separating compared to traditional network architecture. In this paper, we survey network traffic engineering in SDN. We investigate and cluster the articles published between 2017 and 2022 on traffic engineering in SDN. The state-of-the-art articles about the traffic engineering mechanisms in SDN have been examined and classified into four types: topology discovery, traffic measurement, traffic load balancing, QoS, and dependability. Finally, the cutting-edge issues and challenges are discussed for future research in SDN-based TE.

如今，许多应用程序需要不同级别的服务质量 (QoS)。提供通信服务的网络连接服务器和客户端。应该设计通过网络路由的网络流量。流量工程 (TE) 是一种考虑应用程序之间不同 QoS 级别要求的数据包传输机制。优化资源分配是 TE 的主要策略，以便网络可以为每个应用程序提供 QoS 要求。TE可以提高网络效率、性能和用户满意度。软件定义网络 (SDN) 已被提出作为一种新颖的网络架构，与传统网络架构相比，它可以通过控制和数据平面分离使网络变得灵活、可管理和可编程。在本文中，我们调查了 SDN 中的网络流量工程。我们对 2017 年至 2022 年间发表的关于 SDN 流量工程的文章进行调查和聚类。关于 SDN 中流量工程机制的最新文章已经过审查并分为四种类型：拓扑发现、流量测量、流量负载平衡、QoS 和可靠性。最后，讨论了基于SDN的TE未来研究的前沿问题和挑战。