OpenDayLight OpenFlow OpenVSwitch

OpenDayLight is a SDN controller that provisions the network policies as specified and sends that information to the Hypervisor. As a controller it also performs the role of maintaining those policies in spite of the changes happening in the network, recomputing policies and pushing to Hypervisors.

OpenFlow is the protocol used to program the Hypervisor vSwitches like traffic flow and is the protocol throughwhich an SDN controller communicates with the hypervisors.

OpenVSwitch is the implementation of a virtual switch in the Hypervisor that exposes OpenFlow protocol for flow information and uses the so called information provided via this protocol ot make packet forwarding decisions.

SDN helps users virtualize the hardware and works to create a computer network by breaking down the network into the following separate planes:

1. The control plane offers the performance and fault management of OpenFlow protocol, is frequently used for managing device configurations that are remotely connected to a software-defined network.
2. The data plane forwards traffic to its desired destination. Before traffic reaches the data plane, the control plane dictates what path flows it will take by using the flow protocol— when a network administrator works with the software-defined network and manages the network.

Traditional networking consists of the following traits:

1. The functions of traditional networking are primarily implemented from dedicated devices using one or more switches, as well as routers and application delivery controllers.
2. The functionality of traditional networking is largely implemented in dedicated hardware and thus traditional hardware-centric networking comes with limitations.

Therefore, the most notable difference between SDN and traditional networking is that SDN is software-based while traditional networking is usually hardware-based. Because it’s software-based, SDN is more flexible, allowing users greater control and ease for managing resources virtually throughout the control plane.

Traditional networks use switches, routers and other physical infrastructure to create connections and run the network.

SDN controllers feature a northbound interface that communicates with APIs. Because of this communication, application developers can directly program the network, as opposed to using the protocols required by traditional networking.

SDN lets users use software to provision new devices instead of using physical infrastructure, so IT administrators can direct network paths and proactively arrange network services. Unlike traditional switches, SDN also has the ability to better communicate with devices using the network.

Virtualization is the primary difference between SDN and traditional networking. When SDN virtualizes entire network, it generates an abstract copy of your physical network.

While in a traditional network, the physical location of the control plane complicates the ability to control the traffic flow.

With SDN, the control plane becomes software-based, allowing it to be accessed through a connected device.

A decentralized SDN is one that enables both physical and logical distribution of the SDN control plane