Software-defined Networking


Software defined Networking (SDN) is a new approach to designing, building and managing networks. SDN definitions vary.

The three main definitions of SDN are:

1) Pure SDN

2) SDN via APIs

3) SDN via overlays.

Pure SDN:

The Open Networking foundation’s definition of SDN is: “This architecture decouples the network control and forwarding functions enabling the network control to become directly programmable and the underlying infrastructure to be abstracted for applications and network services. The OpenFlow™ protocol is a foundational element for building SDN solutions”

In this scenario the control plane or “brain” of a network device is moved from a network device and resides in an external controller which has a centralized view of the network. Network devices such as routers and switches only maintain keep the data or forwarding plane and no longer have a control plane.

This is often viewed as the classic definition of SDN and is often called pure SDN.

SDN via APIs:

Another definition of SDN is SDN via Application Programming Interfaces (APIs). In this scenario, networking devices maintain a local control and data plane, but have enhanced or richer APIs for device management and configuration.

SDN via overlays:

In this scenario, a virtual network using tunnels is overlaid across an existing physical network. The virtual network can be programmed and dynamically updated quickly from a controller running within a hypervisor. The physical network of routers and switches is not programmed (except in certain cases). Overlay technologies such as VXLAN are used to create the virtual overlay network.

Computer Data, Inc. and SDN:

Computer Data, Inc. has designed and written multiple courses on OpenFlow and SDN and deliver training on these emerging technologies worldwide.

Computer Data, Inc. also develop SDN applications to enhance and optimize network functionality.