Software Defined Networking is a paradigm that emerged in the networking industry recently. This technology is not mature yet, but is gaining momentum, driven by the fact that traditional networks began to show their limitations. Many standardization activities are still ongoing, given the fact that there are many aspects of a network that SDN touches upon, and having the right tools to support these efforts is important. The Wireless Transport Emulator (WTE) was designed for supporting the standardization endeavors of the Wireless Transport Group, part of the Open Networking Foundation (ONF), a consortium that aims to promote SDN adoption through defining open standards. WTE uses different technologies in order to simulate a wireless transport network, consisting of emulated Network Elements, that implement a Microwave Information Model, TR-532. It consists of a NETCONF server implementation that advertises the TR-532 information model, and the link representations based on Open vSwitch (OVS) bridges and a Python framework that glues everything together. The tool is also extremely useful for SDN application developers that want to create applications using the aforementioned information model, because it eliminates their need of owning real, expensive, wireless transport devices in order to test the functionality that they are developing.
Software-Defined Netowrks, Wireless Transport, Open Networking Foundation
Computer networks have become, nowadays, complex and increasingly challenging from the configuration and setup point of view. Therefore, the need for key architectural changes to the paradigm of networking has risen. Software-Defined Networking (SDN) emerged around the year 2009, from the work that was done in Stanford University in the context of the OpenFlow project. It is a revolutionary approach in networking, which focuses on mitigating the limitations proven by traditional networks. The concepts proposed by this paradigm are not new, some being even 25 years old, but the timing was not right at the time, thus their adoption in the industry was not possible then.
SDN proposes a novel network architecture, where the forwarding state of the data plane is managed by a distant control plane, decoupled from the data plane (Stancu 2015). In this way, network devices become simple packet forwarding devices, while the control logic or the control plane is implemented in what is called the controller. This has numerous advantages, from being able to much more easily introduce new policies in the network through software, to being able to centrally configure all network devices instead of configuring individually each one. This way SDN can provide enhanced mechanisms for network management and configuration.
SDN can be used for optimizing the radio (e.g. remote radio units - RRUs and baseband units - BBUs) and transport (e.g. optical cross connects, microwave links) resources in future 5G systems. These resources can be managed by centralized controllers, on top of which an orchestrator may be placed. Therefore the SDN orchestrator has to be exposed to an adequately detailed abstraction of these resources.