While talking about networking you might have noticed that the word "protocol" is used several times. This is because protocols are the special set of rules that allow computers with dissimilar operating systems, network topologies, hardware, etc. to communicate with each other.
Protocols operate at many layers of the network models described below. There are protocols considered to be transport protocols such as TCP and UDP. Other protocols work at the network layer of the OSI network model and some protocols work at several of the network layers.
Protocols can be implemented either in hardware or software, or a mixture of both. Typically, only the lower layers are implemented in hardware, with the higher layers being implemented in software.
