In networking, layering means to break up the sending of messages into separate components and activities. Each component handles a different part of the communication. This can be referred to as the Transmission Control Protocol/Internet Protocol (TCP/IP) model.
There are four layers to be considered:
Layering allows standards to be developed, but also to be adapted to new hardware and software over time. For example, different software packages (applications) may use the same transport, network and link layers but have their own application layer. The way the program encodes the message changes - the rest of communication method remains the same.
Similarly, the move from IPv4 addressing to IPv6 affects only the network layer - the other layers remain unaffected. This allows improvements to be made without having to redefine whole communication methods.