SDN and Wi-Fi Part 1 – SDN Background

The purpose of this blog is to define what Software-defined Networking (SDN) is and to start a dialogue around what this could mean for Enterprise Wireless Local Area Networks (WLANs). The first part of the blog involves defining SDN, what is driving it, what the benefits are, how it impacts us today and how it will impact us in the future. The final phase involves starting a dialogue around what this does and could mean for Enterprise WLANs.

Evolving from work initially done at UC Berkeley and Stanford University in 2008, Software-defined Networking (SDN) is a new and innovative approach to designing, building and managing networks. SDN decouples or separates the function that makes decisions about where traffic is sent (the control plane), from the function that forwards the traffic (the data or forwarding plane). Typically both the control plane and data plane functions reside on a single specialized physical piece of network equipment for example a router, switch, WLAN controller or Access Point (AP). With SDN however, global control of the network is achieved by the logical centralization of the control plane function in a software controller. Network administrators can deal with a pool of data plane devices (virtual or physical) as a single entity. Network flows are controlled at the level of the global network abstraction, rather than at the level of the individual devices. This is done with a Southbound Application Programmatic Interface (API), most notable being OpenFlow. OpenFlow is an open standard for a communications protocol that enables the control plane to interact with the data plane. It must be noted that OpenFlow is not the only protocol available or in development for SDN.

Another key characteristic of Software-defined Networking is providing open Application Programmatic Interfaces (API) into network equipment. SDN allows enterprises to replace a manual proprietary interface into networking equipment with an open, Application Programmatic Interface (API) that can enable the automation of tasks such as configuration and policy management and can also enable the network to dynamically respond to application requirements. This interface is typically referred to as the Northbound API and facilitates innovation, efficient service orchestration and automation.

The explosion of mobile devices, the need for always-on anywhere access, server virtualization, and the rise of cloud services are among the trends driving the need for a new and innovative approach to designing, building and managing networks. Some of the key trends driving the need for Software-defined Networks include: Within the enterprise network, traffic patterns have changed significantly. In contrast to client-server applications of yesteryear where the bulk of communication occurred between one client and one server, today’s applications access different databases and servers creating an avalanche of traffic; Users are pushing for corporate access from any mobile device including smartphones, tablets and laptops anywhere and anytime (even their own, Bring Your Own Device (BYOD)). The enterprise is under pressure to accommodate these devices while protecting corporate data and intellectual property;  Many enterprise network managers have enthusiastically embraced or are considering a utility computing model which could include a public cloud, private cloud or a hybrid of both resulting in yet more traffic across the network and additional security, compliance and auditing concerns.

Software-defined Networking enables the enterprise to address the high-bandwidth, dynamic nature of today’s applications, adapt the network to ever-changing business needs, and significantly reduce operations and management complexity. Some of the benefits enterprises can achieve through Software-defined Networks include: Centralized management and control of networking devices from multiple vendors; Improved automation and management by using common APIs to abstract the underlying networking details from the orchestration and provisioning systems and applications;  Rapid innovation through the ability to deliver new network capabilities and services without the need to configure individual devices or wait for vendor releases; Programmability by operators, enterprises, independent software vendors, and users (not just equipment manufacturers) using common programming environments; Increased network reliability and security as a result of centralized and automated management of network devices, uniform policy enforcement, and fewer configuration errors; More granular network control with the ability to apply comprehensive and wide-ranging policies at the session, user, device, and application levels across wired and wireless networks; Better end-user experience as applications exploit centralized network state information to seamlessly adapt network behavior to user needs.

Now that you have good background information on SDN, check out part 2 where I start a dialogue around what this could mean for Enterprise WLANs.


Author: Kenneth Fernandes

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