What is Network Function Disaggregation (NFD)?


Network Function Disaggregation (NFD) defines the evolution of switching and routing appliances from proprietary, closed hardware and software sourced from a single vendor, towards totally decoupled, open components which are combined to form a complete switching and routing device.

Historically, network switches and routers have been vertically integrated products delivered entirely from a single vendor. Network architects and engineers must anticipate the most important characteristics of a new networking product based on the specific application (i.e. data center, CPE/VPN or carrier transport) and architectural location (i.e. premise, edge, access/aggregation or core). They then select an appliance by evaluating the individual composition, form factor, features and performance of many distinct offerings.

Ultimately, networking products or solutions are chosen by making significant compromises in areas that are deemed less important to the initial use case. With this purchasing model, concessions must always be made: The need for a robust hardware platform results in the implementation of a device with a less-than-adequate Application Specific Integrated Circuit (ASIC) base. The desire for a particular network operating system and management tools means the deployment of a platform with a networking protocol stack which might not be as robust as others on the market.

Network function disaggregation represents a dramatic departure from the way these critical devices are designed and built, thereby solving these deployment challenges. Employing commercial off the shelf (COTS) x86, ASIC or programmable merchant silicon (within generic servers or white box switches), disaggregated devices are horizontally integrated, where the network operating system (NOS), layer 2 / layer 3 networking protocols and the element management interfaces can be independently selected and easily integrated depending on each specific requirement. This results in a unique, bespoke, product that is perfectly tailored for each application.


Legacy network appliances versus those employing network function disaggregation principles

The adoption of network function disaggregation principles enables network operators to select the best combination individual hardware and software components while eliminating vendor lock-in and anticompetitive sales or support practices.  In turn, capital and operational expenditures can be significantly reduced. Although operator skill-sets must adapt to this new model, along with that of the supplier or systems integrator, benefits are found in a solution which is both highly flexible and easily adaptable to today’s dynamic software defined network (SDN) infrastructures.