A protocol is an agreed set of rules for how two parties format, send and acknowledge data. Devices, buses and networks all depend on protocols so that independently built components can interoperate.
In practice
A networked printer may accept jobs through one protocol for discovery and another for printing. Wi-Fi itself follows protocol standards defining how adapters and access points negotiate connections and encryption.
Common confusion
Protocol is not the same as the physical medium. The same Ethernet cable carries many protocols, and one protocol can travel over different media. A protocol also differs from a driver: the driver implements the protocol for one device.
Why it matters to readers
Release notes often mention protocol versions, such as compatibility for a newer Wi-Fi standard. Knowing that the protocol must be integrated by both ends explains why a driver update alone may not enable a feature.
A closer look
Protocols are usually defined in layers, with each layer relying on the one below. A web page travels over network protocols, which travel over Wi-Fi or Ethernet protocols, which travel over radio or copper. A network adapter driver mostly concerns the lower layers, while applications handle the upper ones, which is why driver notes rarely mention websites.
