SDN – WHY IS THE BUZZ AROUND?
SDN (Software-Defined Networking) is defined as “The physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices”. This is the standard definition of SDN as defined in ONF Site. https://www.opennetworking.org/sdn-definition/
Don’t worry; if you are not able to make out of SDN (Software-Defined Networking) from the above definition. Let’s try to get a sneak view on why this solution has emerged as a technology life saver in recent years and how one can leverage it in a practical way
Technology revolution is realized through innovation is one of the three underlying fundamental domains of IT – Compute, Storage & Network
Cloud computing has taken the world by storm in the last decade and it continues to transform IT in unprecedented ways. The real tangible outcome of Cloud Computing is XaaS (everything as a service) which has significant cost-saving benefits (CAPEX/OPEX) for enterprises. Scenarios where apps are majorly deployed in an enterprise network, are now slowly migrating to cloud service, or at least embracing hybrid cloud to lower the Total Cost of Ownership (TCO)
Moore’s Law seemed relevant until now – the law conveys that the per unit computing power doubles in every 18 months. This symbolizes the exponential growth in computing power and therefore in server technology. However, the bitter truth is that the Data queued up for compute processing is outpacing existing computing power itself. The proliferation of data driven application, AI (Artificial Intelligence) & ML (Machine Learning) has pumped the networks with more data than ever before and it is still to reach its peak.
This has put transport networks under tremendous stress. The cloud service base models demand innovation in network technology as well which is still driven by vendor monopolistic market and strongly hardware centric majorly relying on technology churn in ASIC. Traditional network runs on legacy hardware which bottlenecks its on-demand programmability and automation.
For an example: Creating and enabling VM in cloud service is less than a few seconds job while the underlying network still requires days to align with services to be provisioned.
The technology which comes to the rescue here is SDN (Software defined networking).
The network switch, in general, comprises of a forwarding plane and a controlling plane. SDN (Software-Defined Networking) steals the controlling plane from the networking hardware (be it a Switch -L2/L3, Router or FW).
This implies that the intelligence of network is abstracted from the device to enable on-demand provision of network resources from application space.
HOW SDN WORKS?
A network device fundamentally performs two operations: Forwarding and controlling. Forwarding is switching data between ports based on the information available on switch table. The control plane fills up the table based on the protocols logic.
In SDN (Software-Defined Networking), the controlling plane is abstracted from the switch hardware to run in virtualized environment.
The switch without having control plane is referred to as “Whitebox”. Whitebox switches are Industry Standard, off-the-shelf switches. It is similar to x86 based platform which is called ISS (Industry Standard Server). Traditionally, switches are built with dedicated hardware and proprietary Network operating systems. With these new commodity switches, features are software-defined. This is the cultural change in network hardware. Think about L2 switch purchased to setup a small network. Imagine converting this switch into L3 switch or a router. This may sound impossible with traditional vendor specific switches in business today. However, with Whitebox switches, this seems quite achievable.
The controlling plane can then be guided by the application to provision network routes on demand. This provides greater flexibility and controllability of LAN, WAN, datacentre and Cloud environment. SDN uses Open Flow protocol to communicate with Network device.
SDN controller is an application in an SDN architecture which actually tells Whitebox switches where to send packets. SDN controller is available as an open source and closed source. Few well known opensource controllers are OpenDayLight (ODL), Floodlight, Ryu and Flowvisor.
HOW SDN IS GOING TO BENEFIT?
- Ease of Provisioning: Network and Internet service providers would have better control over the quality of service without having need to expand the capacity. They can allot the network space based on the user need without having to change under laid network hardware and configuration.
- Security: Centralized control could result in advanced network policy-setting and enforcement through visibility and the ability to route individual flows to specific devices.
SDN use cases: There is an excellent article on SDN use cases relevant in various domain. https://www.sdxcentral.com/sdn-nfv-use-cases/