June 13, 2019
By Hassan Dakroub, Customer Solutions Architect
The wave of virtualization is catching up in every vertical of technology, and new protocols are being defined to improve functionality and management of emerging technologies. Software-defined Networking, or SDN, is one of those technologies. SDN was first used in data centers to configure network devices connecting virtual machines amongst themselves and the internet on a massive scale and is now being adapted into other applications and technologies.
At a high level, SDN allows better control of devices in a network and enables automation of functionality within the network. Prior to SDN, network devices consisted of separate control and data planes within the same device which required individual configuration or programming of each device. The data plane forwards traffic from one port to another within the same network box, while the control plane determines the ingress and egress ports for each data stream and pushes that information to the data plane. The control plane makes the forwarding determination by either using user-defined static configuration or using protocols to communicate with other network devices. These protocols discover what every surrounding device knows about the network, and then makes the calculation for the shortest path for each traffic stream. This process works but requires individual instructions to each network element, which can slow down as the number of executable instructions increases. Like everything in the networking space, this method was long overdue for some course correction to improve efficiency and speed and led to the birth of SDN.
SDN centralizes the control brain and localizes the “brain” in the network. This separation of the control and data planes is done by centralizing the control plane of networking devices into an SDN controller. This allows a network operator to configure the network from a central location and add new services or update existing services without having to log in to every network device affected by the change. This reduces the time to configure the network and makes the operation of the devices much simpler. Additionally, the centralized control plane simplifies automation in the network. This is because a centralized control plane has constant visibility of the network and devices which can determine network conditions, changes, and parameters and allow custom-built applications to be implemented in the network. These applications will enable dynamic intelligence that will lead to improved performance and of the devices and the network by being able to predict network performance and dynamic correction/adjustment based on the performance.
We will discuss the various elements of SDN over subsequent posts and we’ll start by discussing three protocols and model languages that are essential for the operation of SDN. These protocols are the YANG data model, Netconf, and Restconf.
New protocols such as SDN, NETCONF, RESTCONF, YANG data Model, as well as devices that support these protocols, empower this new technology wave to simplify network management, and automating it, in a multi-vendor, multi-functionality network. This also makes supporting new technologies and services possible as they emerge, without having to forklift the whole network.
References: