Software Defined Networking (SDN) is receiving a lot of attention lately, and it’s not just from customers. Vendors and channel partners are conducting industry events focused on increasing awareness about the benefits of SDN. Optimism is high and many think SDN is networking’s Next Big Thing.
Rather than a specific technology, SDN is an approach that introduces programmatic network management to allow upper-layer dynamic management of network resources. With the current mature virtualization of most infrastructure components such as servers and storage, the industry urges network virtualization to increase network agility. This completes infrastructure virtualization, a vital requirement for supporting cloud services.
SDN versus traditional networking
Traditional networking devices such as routers and switches are independent. Each device decides how to send its traffic as network admins configuring policies that control traffic flow through each device. Each individual device has two separate components that work together to transport traffic through the network: A control plane, the brains of the device that decides where traffic should be sent, and a data plane which is responsible for forwarding data.
This is the traditional network structure that we’ve used for years. Many trials produced software and networking tools that, at best, enhanced configuration management on many devices at the same time. Still, however, each device would interpret these configurations via its brain and cascade the decision to the underlying forwarding plane. Virtualization efforts focused on creating sub-instances of the same device rather than building a virtual network over the physical infrastructure.
SDN is a different story. With SDN, networking devices are managed and configured from a central system called an SDN controller. The controller decouples the decision-making component (control plane) in networking devices from the data forwarding component (data plane). It then centralizes the control plane outside of the network device and enables it to become programmable by external services, mainly the applications.
This creates a dynamic and flexible networking infrastructure that allows for a more efficient automation of different networking services.
SDN also aims at creating higher virtual network layer over the physical one which allows for creating separate network domains for different applications and/or customers. All new logical network devices and services such as routers, switches, firewalls and load-balancers run over the physical network. For years, the network was the major part of infrastructure lacking virtualization. With SDN comes the promise of virtualizing the network to support increasingly virtual environments.
At first glance, SDN adoption seems like a no-brainer. It’s still in the early stages, however, of gaining entry to data-centers. This is normal with any new technology as the majority tend to be skeptical of early adopters. As more success stories come about more companies will be interested in deploying SDN in their data-centers.
Presently, there are ongoing active SDN projects in various phases. While some companies are still evaluating the technologies in Proof of Concepts (PoC) efforts, others are already deploying and fully operating them SDNs. The more IT professionals know about SDN and how they can benefit, the rate of deployment will certainly pick up.
If you are a system administrator contemplating a move to SDN, here are the main advantages and challenges to consider.
Flexibility: Decoupling networking controls and forwarding functions makes introducing changes on the network more flexible from a centralized controller.
Fast service provisioning: SDN promises to fill the gap between software and networking. With SDN, software applications can quickly and automatically provision required network resources without manual configuration.
Cloud support: As many companies migrate to the cloud, virtualized and centrally managed infrastructure is a key to support. SDN enables easy virtualizing of the networking infrastructure.
Centralized management: SDN lets administrators manage different systems from a central console.
Infrastructure changes: Moving to an SDN infrastructure requires making changes to your current infrastructure. While some SDN solutions are free and open-source, others require purchasing licenses and/or replacement of current devices.
Controller reliability: Because a single controller oversees all network resources, it must have high reliability to ensure network availability.
Knowledge development: Since SDN is different from a traditional infrastructure, companies will have to invest in the training and development of current engineers or hire and integrate new ones into the team to be able to support the infrastructure.
Cinter Unison Networks
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