SDN Focus Shifts to Network Services

Brad Casemore is Research Director for IDC’s Datacenter Networks practice and is a featured guest blogger.

Cloud computing requires a datacenter network and corresponding network services that are more flexible and responsive than traditional datacenter network architectures. Responding to that need, software-defined networking (SDN) has emerged as a means of realizing network virtualization and network programmability, while also ensuring that the network can deliver the virtualized network and security services that are essential to the provision of scalable multi-tenant services.

In an SDN model, network services — such as load balancing – can be virtual applications that run on an SDN controller, which is decoupled from the data path and has global network visibility, thus ensuring that cloud application workloads are optimally handled by the network. This approach of virtualized network services in an SDN architecture provides service velocity, flexibility, scalability, and operational savings that are perfectly suited to the demands of cloud computing.

By its very nature, software-defined networking (SDN) is about putting the applications in the driver’s seat, ensuring that the receive what they need from the underlying physical network, and from higher-layer network services, to operate at peak efficiency and to deliver business benefits. IDC defines SDN according to the following criteria:

• Dynamic exchange between applications and the network
• Delivering programmable
  interfaces to the network
• Management abstraction
  of the topology
• Separation of control and
  forwarding functions

Early in SDN’s development, much of the emphasis was placed on OpenFlow, an open protocol that facilitates decoupling of the control plane from the data plane, effectively allowing the forwarding table of a switch to be programmed by controller software resident on a server. While OpenFlow plays a valuable role in facilitating flow forwarding on a switch, not as much of the initial discussion focused on Layer 4-7 services.

Since then, however, the discourse has moved up the SDN stack, with increasing interest in how network and security services should be best delivered within an SDN architectural model. The application delivery controller (ADC), as an integral element between the applications and the underlying network infrastructure, clearly has an important and evolving role to play in SDN deployments.

Indeed, just as server virtualization led to the proliferation of cloud services, IDC expects the continued spread of virtualization, cloud computing, and now network virtualization to lead in 2013 to a significant increase in virtualized network and security services, including load balancers and firewalls. This will occur in datacenters spanning enterprises and service providers, and major vendors as well as start-up players will serve as prominent suppliers.

Customers, especially those adopting private and public cloud, will benefit from gains in the relative speed and simplicity of service provisioning, and vendors, including Radware, will be seeking to meet their requirements.