Software-Defined Networking Drives the Transition from Configurable to Programmable Networks

This Industry Viewpoint was authored by Stephen Collins, Vice President of Product Marketing and Business Development at Active Broadband Networks

Fixed broadband providers are struggling to accommodate explosive growth in bandwidth consumption while also satisfying the needs of their subscribers. In order to remain profitable, operators need to reduce the cost and complexity of broadband service delivery while improving customer quality of experience. In order to do this, broadband providers must make their networks more flexible, adaptable, and capable of delivering services that are managed dynamically by their subscribers.

Broadband providers have to move beyond provisioning static services mainly on the basis of connection speed to offering dynamically managed services that factor in bandwidth consumption, quality of service and time of day to better satisfy the needs of residential and business broadband customers. Software-defined networking (SDN) will be instrumental in achieving this goal by driving the transition from today’s configurable networks to fully programmable networks that will better suit the needs of a wide range of applications, services and users.

Constrained by Today’s Configurable Network Infrastructure

Existing broadband network infrastructure is dynamically reconfigurable, but operators and their subscribers are constrained by a predefined set of configuration parameters that determine the behavior of the underlying hardware and the various protocols utilized for dynamic policy control. The network can adapt to the needs of applications or users only to the extent that the underlying infrastructure can be reconfigured, either manually through a labor-intensive process or automatically using a policy server.

Policy is Not Software-Defined Networking

Policy servers have helped make the network more agile by enabling applications to dynamically reconfigure networks, but they are still constrained by the pre-defined scope of standardized service configuration protocols (e.g., PCMM, Radius and Diameter) that are used to communicate with the underlying network infrastructure. Applications are unable to directly program the network elements and network elements cannot expose features or capabilities that don’t fit within the policy protocol without revising the existing standard and upgrading software (and possibly hardware) in all affected elements.

SDN Allows Direct Programmatic Control of Network Elements

Software-defined networking removes the abstraction layer imposed by policy to allow direct programmatic control of switching or forwarding tables in network elements. This direct programming model frees the developer to envision applications without the constraints of a pre-defined, configuration-based policy abstraction layer, and enables network element vendors to expose functionality that can be combined in any way by the application developer to deliver existing services more efficiently, or create completely new applications that directly leverage network capabilities.

What It Means for the Future of the Network

The shift from configurable to programmable networking will have a profound impact on the way networks are operated and network services are sold. A programmable network will allow network behavior to be modified in real-time and new applications and network services to be deployed rapidly, independent of vendor development cycles. This will enable operators to reduce the cost and complexity of broadband service delivery while better serving the needs of subscribers.

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Categories: Industry Viewpoint · SDN