White-box networking means buying plain network switch hardware from one company and running a network operating system from another company on it. The hardware is called a white box, because it carries no big brand. The software is the network operating system (NOS), the program that runs the switch and decides how it handles traffic. A well-known example is SONiC, an open-source network operating system that Microsoft first wrote for its own data centres and then released for anyone to use.
A branded switch comes as one locked package. The same company makes the hardware and the software, sells them together and supports both. With a white box, the buyer chooses each part separately. This separation of software from hardware is called hardware-software disaggregation. The same idea, applied to the equipment on mobile towers, is Open RAN.
Why would a buyer do this? There are three reasons. The first is price. White-box hardware is often built on the same networking chips as branded switches, but it costs less. The second is choice. The buyer can change the software without replacing the hardware, or change the hardware maker without retraining its engineers. The third is control. A buyer with a large engineering team can add features itself, and use the same software and tools on every switch.
Consider a cloud provider in Jaipur that runs 600 switches across two data centres. It buys white-box switches from one maker and runs SONiC on all of them. When the provider wants a new monitoring feature, its own engineers write it once and install it on all 600 switches in one evening. Later, it buys its next 200 switches from a different hardware maker. Its engineers keep the same software and the same tools.
There is a cost. With a branded switch, one company answers for every problem. With a white box, the buyer must work out whether a fault is in the hardware or in the software, or pay a company that supports the open software. So white-box networking is used mostly in the largest data centres, by cloud companies, telecom operators and builders of AI clusters. Most other buyers still buy branded data centre switches. Many new switches built for AI cluster networking also run SONiC.