Sublayer

In telecommunication, the term sublayer has the following meanings:

1. In a layered open communications system, a specified subset of the services, functions, and protocols included in a given layer.

2. In the Open Systems Interconnection--Reference Model, a subdivision of a given layer, e.g. , a conceptually complete group of the services, functions, and protocols included in the given layer.

Source: from Federal Standard 1037C