| 释义 |
protocol layer protocol layer (networking)The software and/or hardware environment oftwo or more communications devices or computers in which aparticular network protocol operates. A networkconnection may be thought of as a set of more or lessindependent protocols, each in a different layer or level.The lowest layer governs direct host-to-host communicationbetween the hardware at different hosts; the highest consistsof user application programs. Each layer uses the layerbeneath it and provides a service for the layer above. Eachnetworking component hardware or software on one host usesprotocols appropriate to its layer to communicate with thecorresponding component (its "peer") on another host. Suchlayered protocols are sometimes known as peer-to-peerprotocols.
The advantages of layered protocols is that the methods ofpassing information from one layer to another are specifiedclearly as part of the protocol suite, and changes within aprotocol layer are prevented from affecting the other layers.This greatly simplifies the task of designing and maintainingcommunication systems.
Examples of layered protocols are TCP/IP's five layerprotocol stack and the OSI seven layer model. |