Basic elements of a computer network include hardware, software, and protocols. The interrelationship of these basic elements constitutes the infrastructure of the network.

A network infrastructure is the topology in which the nodes of a local area network (LAN) or a wide area network (WAN) are connected to each other. These connections involve equipment like routers, switches, bridges and hubs using cables (copper, fiber, and so on) or wireless technologies (Wi-Fi).

If we think of a network as roads, highways, rails, and other means of transport, the network protocols are the "traffic rules." The network protocols define how two devices in the network communicate. The specification of the network protocols starts with the electrical specifications of how a networking device is connected to the infrastructure. For example, line voltage levels, carrier signals and the designation of which line might be used for what types of signals must all be specified. Building up from there, network protocols include such specifications as the methods that can be used to control congestion in the network and how application programs will communicate and exchange data.

A popular method of documenting network protocols is to use a layered network architecture model. Network architecture models separate specific functions into layers, which collectively form a network stack. While a protocol consists of rules that define characteristics for transporting data between network nodes, the layered model separates the end-to-end communication into specific functions performed within each layer.

Ideally, the layers are isolated from each other: each layer does not need to know how the layer below it functions. All a layer needs to know is how to interact with the layers adjacent to it. You can learn more about network layers in the topic on network layers and protocols.

Today, TCP/IP is by far the most dominant suite of networking protocols. Prior to TCP/IP, SNA was arguably the dominant protocol suite. There is some irony here, because TCP/IP is the older of the two protocols. Many networks in larger organizations are using both of these protocol suites. As with most networking protocols, both SNA and TCP/IP are layered protocol stacks.