Because of the history of the protocols being discussed here (See the section called History ) and lack of standards, there is often confusion in the use of some of the terms; it is not uncommon to hear statements of the form "NetBIOS is not a protocol" or "NetBEUI is a protocol".

NetBIOS is not a protocol

As described in the history above, NetBIOS was designed as an interface. NetBIOS was designed to be an extension to the BIOS (Basic Input/Output System) of PCs to provide networking services. At the risk of being pedantic, NetBIOS was designed as an application programming interface (API). It is interesting (and the source of some confusion) that it was the API which was the standard.

NetBIOS is a protocol

The term "protocol" is often used as a shorthand reference to a suite of protocols (a well-known example is the use of the term "TCP/IP protocol" to refer to a collection of protocols). The informal use of the term "protocol" is well-understood and accepted practice. It has become standard practice to use the term "NetBIOS protocol" to refer to the original set of protocols in use with the NetBIOS API and the protocols which followed. The current official term used by IBM is "NetBIOS Frames Protocol" (NBF) and it is not unreasonable to shorten this to "NetBIOS".

NetBEUI is not a protocol

If NetBIOS is not a protocol, but is an API, then an "Extended User Interface" to this API is also not a protocol. As mentioned above, and described in the history, when IBM developed Token Ring it was continuity of the API to ensure applications would continue to function which was important. The NetBIOS API was preserved and extended in the NetBIOS Extended user Interface, NetBEUI.

NetBEUI is a protocol

With the development of NetBEUI, a set of protocols was developed, now known as the NetBIOS Frames Protocol. Since the NetBIOS Frames Protocol was used with the NetBEUI API it became accepted practice to refer to these protocols as the "NetBEUI protocol". It is still common to find documentation which refers to the "NetBEUI protocol".