A network infrastructure is an interconnected group of computer systems linked by the various parts of a telecommunications architecture. Specifically, this infrastructure refers to the organization of its various parts and their configuration — from individual networked computers to routers, cables, wireless access points, switches, backbones, network protocols, and network access methodologies. Infrastructures can be either open or closed, such as the open architecture of the Internet or the closed architecture of a private intranet. They can operate over wired or wireless network connections, or a combination of both.
The simplest form of network infrastructure typically consists of one or more computers, a network or Internet connection, and a hub to both link the computers to the network connection and tie the various systems to each other. The hub merely links the computers, but does not limit data flow to or from any one system. To control or limit access between systems and regulate information flow, a switch replaces the hub to create network protocols that define how the systems communicate with each other. To allow the network created by these systems to communicate to others, via the network connection, requires a router, which bridges the networks and basically provides a common language for data exchange, according to the rules of each network.
When multiple computers in a single household share the same Internet connection, it is considered a basic form of network infrastructure, whether or not the computers also share information with each other. The Internet itself is a more advanced network infrastructure, in which individual systems access a global network that houses information on various systems, and allows access using web standards and protocols, most commonly framed as web addresses, also known as URLs.
Office intranets are similar to the global Internet, but operate on a closed network infrastructure accessible only by those within it. This generally consists of a central data store — one or more computers known as servers — as well as ethernet cabling, wireless access points, routers, switches, and the individual computers with access to the central data store. The individual computers connect to the network via either cabling or wireless access. The routers and switches then determine what level of access they are allowed to have, and act as traffic directors to point them to the central data store on the servers. As the individual computers send or receive data, the routers ensure it reaches the appropriate place.
Network security is often a primary concern when building a network infrastructure. Most architectures use routers with built-in firewalls, as well as software that allows finely-tuned user-access control, data packet monitoring, and strictly defined protocols. Security can also be controlled by adjusting network sharing properties on individual systems, which limits the folders and files that can be seen by other users on the network.