A few weeks ago, we planted the seed of SDN being a salvation for carriers, but how exactly does that happen? While there are many reasons why carriers should join the SDN revolution, they must first understand how the technology benefits them directly.
When thinking about the network structure, it is important to remember that one if its key features is separating the data plane from the control plane, both functionally and physically. This means that custom equipment like switches no longer have to determine where a packet should go and then route it. With SDN, the intelligence is separate from the process of moving the bits, and a logically centralized control to dynamically provision and control the network.
The OpenFlow® protocol, a standards based form of SDN, conveys the way packets are forwarded through network switches. This allows relatively simple packet-forwarding devices to be collectively programmed to be a VPN, load balancer, or firewall, for example. In addition, global management interfaces are being defined on which developers can build advanced management and orchestration tools. With these tools, an OpenFlow® based network can be programmed to steer traffic, conserve power, even deliver bandwidth on demand. A pure OpenFlow-based network also offers more transparency, granularity, and simplicity of control for the user. This includes port configuration, security, and routing policies, without placing the dependencies on service providers or cloud providers that MPLS would. It also provides a single converged protocol versus many protocols (MPLS, VLAN, etc.) to ratify and implement in parallel.
Separating the tight coupling of data, control, and management planes allows each layer to evolve independently, enables network virtualization and is crucial for rapid innovation. With SDN, carriers can “slice” bandwidth and other resources based on service, application, or customer need. Rather than operate multiple networks to separate customer and Internet traffic, a carrier could use separate control planes to isolate traffic that shares a common fiber infrastructure.
-Dan Pitt
