SDN is virtualization occurrence that has been occurring at datacenters across the globe for the past several years and extends to computing hardware, storage devices, and network infrastructure.
In fact, by placing a layer of intelligent software between network devices (such as switches, routers, and network cards) and the operating system that talks to the wire, Software defined networking allows IT professional to configure networks with the help of only software.
Similar to virtualization, SDN achieves the same abstraction. With hardware virtualization, the hypervisor inserts between the physical components of a computer and the operating system.
Importantly, the operating system observes the virtualized components and functions with those, and the hypervisor interprets the instructions coming to the virtualized components, which the physical hardware can handle.
That said, one can move virtual machines to various computers made up of distinct hardware till the time hypervisor is adaptable. This is because the operating system in the virtual machine needs to know how to talk to the virtualized components. It gives freedom to configure and reconfigure computers and servers.
Moreover, networks are virtualized so that software can organize how networks are built, and configured. Importantly, the physical network components route the real traffic, and the place where the traffic flow is controlled is called the control plane in SDN.
Emergence of Software Defined Networking
SDN has emerged from virtualization mainly because it is useful in public and private cloud. The cloud has a good amount of network configuration and planning, primarily in disaster recovery situations.
Furthermore, the deployment of SDN is open sourced and supported by various vendors. The vendors implement a set of APIs called OpenFlow. Just picture Open Flow as the engine and mechanics behind implementing SDN. The tools that allow one to configure virtualized networks use Openflow to communicate with various devices on the network.
The best part is that SDN allows an administrator to holistically administer the network with a set of capabilities without worrying about a vendor supporting certain capabilities.
Advantages of SDN
Centralized network provisioning
SDN offers a consolidated view of the entire network, making it simpler to consolidate enterprise management and provisioning. For instance, virtual LAN (VLANs) are becoming part of physical LANs, making a Gordian knot of links. At the same time, by removing the data planes, SDN can propel service delivery and offer quickness in provisioning virtual and physical network devices from a central location.
Holistic enterprise management
Enterprise networks have to establish new application and virtual machines in order to accommodate processing requests for big data. SDN permits IT managers to experiment with network configuration without affecting the network. At the same time, SDN supports management of physical and virtual machines and network devices from a central controller. SDN offers a single set of APIs to create a management console for physical and virtual devices.
Lower operating costs
Administrative efficacy, improvement in server utilization, and control of virtualization leads to operational saving. SDN reduces the operating costs and leads to administrative savings as network administration issues can be centralized and automated.