This editorial introduces the topic area of this special issue, namely the area of Software Defined Networking (SDN) controlled optical transport networks, i.e., so-called transport SDN (T-SDN) networks, that support emerging fifth generation (5G) wireless networks. We first outline the SDN concept and the main challenges and potential benefits of SDN control in optical transport networks. We then introduce the articles of this special issue, which we have categorized into articles addressing: (i) T-SDN control plane architectures, (ii) T-SDN provisioning and restoration, and (iii) control of specific transport technologies in T-SDNs. We conclude this editorial with a broad outline of future research directions related to T-SDNs supporting 5G networks.

这篇社论介绍了本期特刊的主题领域，即软件定义网络（SDN）控制的光传输网络，即所谓的传输SDN（T-SDN）网络，它支持新兴的第五代（5G）无线网络。 。我们首先概述SDN概念以及光传输网络中SDN控制的主要挑战和潜在利益。然后，我们介绍此特刊的文章，我们将其分类为以下文章：（i）T-SDN控制平面体系结构，（ii）T-SDN设置和恢复，以及（iii）T-SDN中特定传输技术的控制SDN。在本社论的结尾，我们概述了与支持5G网络的T-SDN相关的未来研究方向。