Topics, 232 References, 236 5G Transport Network 9.1.1 5G Transport Transport networks for 5G will be more versatile than today and characterized by the different 5G use cases and different network architectures (as described in Chapters 1 and 5) and also by different kinds of operator networks and different operating models. In addition to reducing latency and increasing capacity and user peak rates of the mobile network to a new level, there is a strong tendency to simplify the mobile backhaul and make it robust against failures and abnormal situations, SO that mobile services run uninterrupted over the 5G transport, while minimizing transport operational needs. Security is vital as well as resiliency. From a networking technology standpoint, there at first sight is no dramatic change from LTE where already all the 3GPP logical interfaces were IP (Internet Protocol) based. A special case is the low layer split point, which is now with 5G evolving from the legacy Common Public Radio Interface (CPRI)/Open Base Station Architecture Initia- tive (OBSAI) to standard networking technologies. However, a major evolution in technology is still underway as connectivity relies more and more on IP, due to the availability of IP services for resiliency, security, flexibility, and scalability, with operational and troubleshooting tools. IP (natively or with Multi- protocol Label Switching MPLS) is a common building block for transport services for 5G Technology: 3GPP New Radio, First Edition. Edited by Harri Holma, Antti Toskala, and Takehiro Nakamura. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd. 9 Transport mobile backhaul and is needed even more for 5G. At the same time, low speed links, old transport nodes, and technologies may gradually be retired from the network during the upgrade phase of 5G and replaced with modern solutions. The optical layer, besides supplying large bandwidth for communications, is becoming to a greater extent capable of solving connectivity needs directly in the photonic 