Software Defined Networking (SDN) and Network Function Virtualization (NFV) are significant and exciting developments in the field of computer networking. They are great individually, but when deployed together with automation they deliver a lot of benefits.
What should networks deliver?
Organizations continually strive to provide applications to their users more efficiently and productively to increase revenue, reduce costs, and improve Quality of Experience (QoE). At the same time, IT departments are mandated to provide more agile, automated and more resilient services. The problem is that network services such as application delivery control and load balancing, web application firewalls, intrusion prevention and SSL encryption, can sometimes take days, weeks or even months to provision in data centers, when ideally new application services often need to be deployed immediately to deliver a business requirement.
The fact that traditional IT models are unable to provide this level of service has been one of the primary drivers for the rapid adoption of public and private cloud services. Competition has also forced IT to rethink their utility models, prompting them to consider more flexible technologies, services and methodologies to provide users with the level of cloud services they need, in timelines that are acceptable, and with a good QoE. SDN and NFV have emerged as vehicles to provide that level of infrastructure and network service, while still maintaining visibility, security and control over the environment.
What is SDN?
SDN moves the control and management of the network to a centralized controller and away from network devices. Network administrators can use this controller to shape traffic on the network as required. Introducing this centralized management adds flexibility and allows for rapid configuration of the network as usage patterns change. Effectively the network logic is decoupled from the underlying hardware and deployed in software layers using the virtual data center server technologies that are now standard.
What is NFV then?
NFV does what the name implies and virtualizes network functions such as ADCs (Application Delivery Controllers) and WAFs (Web Application Firewalls). The implementation of network functions in software removes the need for proprietary physical pieces of hardware and allows the network to take advantage of the virtual nature of data center deployments. NFV makes ADC and WAF virtualized functions more accessible to the rest of the infrastructure and provides the framework for service chaining multiple network services. By placing these virtual appliances in a virtual server environment you create a centrally managed infrastructure that reduces cost by not having to maintain and support scores of physical devices. It also improves reliability as misconfiguration and operator errors are minimized with managed configuration scripts controlled via version control mechanisms.
While it’s clearly not a conceptual requirement to implement SDN and NFV together, the capabilities of both technologies complement one another and work well together in supporting a Software Defined Data Centre (SDDC) model. As an example, implementing the concepts of SDN without virtualizing network functions would tie the network to the hardware. This conflicts with the spirit of SDN, which focuses on putting network intelligence in software.
When you are considering a transition to a more dynamic data center architecture aligned to the virtualized applications and services you are running, it’s critical that you:
- Consider the specific functionality you need from each of those network service solutions.
- Determine how well those functions integrate with tools designed to manage, monitor, orchestrate, scale, and move those functions both manually and via automation.
- Make sure that the vendor providing the virtual network services provides control capability tailored to their solutions.
- Ensure that the supplier also provides integration with third-party platforms that perform these functions in compute and mixed/open cloud environments such as Microsoft Azure, Amazon Web Services, VMware vCloud, and in hybrid deployments with on-premise infrastructure.
- Finally, make sure your chosen solution can run both the control functions and data plane function in public cloud environments with the same level of interoperation and integration as they can in your private data center.
Benefits will flow
It’s one thing to provide appliances in a virtual format, but without proper tools to provision, monitor, scale, and manage those virtual services you are just replacing the old hardware with software. This fails to truly deliver the benefits of SDN and NFV. While the cutting edge brings technological and operational benefits, the transition can be painful. By reducing implementation risks, improving efficiency and lowering the barriers to success, using both SDN and NFV means that your data center can be efficient, cost effective and reliable, while also providing greater flexibility and performance. The complementary nature of SDN and NFV makes them perhaps two sides of the same valuable coin and equally critical parts of a modern, efficient virtual network.