Dynamic Networks (SDN/NFV)
Dynamic networks are networking systems that are designed to be adapted to a customer’s needs. Typically, dynamic networking refers to controlling the software of a network to meet a user’s needs. However, before software advanced to being able to control the network, networks were primarily controlled at the hardware level. The process of setting up a large data center with heavy metal servers, cables, and all the cooling and heating meant hardware was very important. When servers and storage were virtualized and their physical locations were moved to off-site locations easily accessible by the Internet, a new degree of flexibility was added to networking. Instead of replacing hardware to change certain network functions, the software could be used to control which hardware to communicate with or how the hardware should handle requests. Since the hardware was “virtualized”, eventually the software used to control, protect, and monitor the servers would be virtualized, too. Two styles of network management came out of this: software-defined networking (SDN) and network function virtualization (NFV).
To understand the fundamental difference between SDN and NFV, say a company called Cool Connections has two customers. Customer A wants to optimize the software end of their Cool Connections network, such as firewalls and deep packet screening to prevent viruses from sneaking in, but they don’t care about optimizing the hardware like switches and routers. Customer B wants to optimize the hardware end of their Cool Connections network, such as configuring switches and routers, but doesn’t care about optimizing the software like firewalls and packets. Since Cool Connections wants to meet both customer’s needs, they would suggest network function virtualization (NFV) for Customer A and software-defined networking (SDN) for Customer B.
NFV and SDN are related to each other and work strongly together, but they don’t have to be integrated together. For example, if SDN was implemented in a network but NFV was not, then the network would be limited by the hardware, reducing the benefit of implementing SDN in the first place.
Software-Defined Networking (SDN)
SDN is a type of network management that focuses on controlling and optimizing the virtualized hardware of a network, such as the routers and switches. SDN utilizes adaptive routing to adapt to changes in traffic flow. In terms of the OSI model, layers 2 and 3 operate independently of the hardware. This allows the developer of an SDN architecture to apply their technology to any network regardless of the hardware that supports it.
Network Function Virtualization (NFV)
NFV is a less common type of network management used to dynamically control the application of software within a network. Originally, network functions like firewalls, traffic load balancing, and routing were covered by hardware devices, but with NFV, these functions are relegated to software applications that can be altered to suit the network’s current needs. NFV operates on levels 3-7 of the OSI model.