Software Defined Networking (SDN) Basics / 101 - Tech | 5G, SDN/NFV & Edge Compute


Wednesday, December 12, 2012

Software Defined Networking (SDN) Basics / 101

What is SDN (Software Defined Networking)? 

Software Defined Networking (SDN) is a network architecture where the control plane is decoupled from the data forwarding plane and implemented as a software application.

Legacy routers and switches had both the control plane and the data forwarding plane implemented in the same hardware appliance. SDN architecture separates the two and makes the control plane run on any standard servers in a centralized location. This architecture provides more programmability and control to the network administrators without requiring physical access to the network's hardware devices that are involved in data delivery.

Also read: 

Need for SDN
SDN Architecture - Protocols & Components

Here is the official definition from the Open Networking Foundation defines SDN, according to an April 13, 2012 white paper:

"Software Defined Networking (SDN) is an emerging network architecture where network control is decoupled from forwarding and is directly programmable. This migration of control, formerly tightly bound in individual network devices, into accessible computing devices enables the underlying infrastructure to be abstracted for applications and network services, which can treat the network as a logical or virtual entity."

Also read: 10 Software Defined Networking Startups

What are the benefits of SDN?
  1. Innovation: Virtualized programmable networks reduces the barrier to entry for new ideas, increasing the rate of innovation in the network infrastructure. For example, researchers can experiment with their ideas on a segment of a production network without impacting it.
  2. New Business Models: Virtualization allows partitioning of network resources and hence, makes it possible for a business model to resell network services.
  3. Ease of Management: A network administrator can shape traffic from a centralized control console without having to touch individual switches
  4. Cost Effective: Allows the administrator to use less expensive, commodity switches and have more control over network traffic flow. 
  5. Flexibility in Vendor Selection: Allows a network operator to mix and match devices from different vendors. Administrator can make independent choices for the control and data plane vendors)
Also read: List of OpenFlow Controllers for SDN

What are the protocols involved in SDN?

The most popular protocol in the SDN world is OpenFlow. 

What is OpenFlow?

OpenFlow is a standard protocol used by a network controller to manage the flow table information in the switches/routers. OpenFlow is used in the communication between control plane and data plane in a Software Defined Network (SDN). It gives access to the forwarding plane of a network switch or router over the network.

OpenFlow protocol originally evolved as a way for researchers to run experimental protocols in the network, has gained popularity over the years.
Who are the major networking vendors that support OpenFlow today?

Brocade Communications, Arista Networks, Extreme Networks, IBM, Juniper Networks, Hewlett-Packard  and NEC have made product announcements regarding OpenFlow. You can find them below. It is surprising to see populare networking product vendors such as Force10, Cisco not having any products that support OpenFlow today - though each one of them have lots of marketing material publishing on OpenFlow.

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