What is "sublayer"

n. 1 A layer underneath another 2 A subunit of a layer

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.