IT infrastructure: According to the ITIL v3, IT infrastructure comprises hardware, software, networks, and facilities. These entities are utilized to develop, test, deliver, monitor, control or support IT services as follows:
A Server refers to a computer with the hardware and software capacity to enable multiple users to access and use its resources. A file server provides users with a central store of files. A directory server operates as a central database of user accounts. Web servers deliver files to users through a web browser using HTTP. Other types of servers are database servers, print servers, and application servers. Even if an organization has moved a big part of its infrastructure to the cloud, it is likely there would be some servers on-premise.
A Data centre is the central part of an organization’s network that usually contains all of the organization's servers and most of its IT infrastructure. A data centre need not be owned by the organization using it, or be located on its premises. Via Colocation businesses host their infrastructure in the cloud and get rid of data centers to reduce costs.
Networking equipment connects servers and user devices (computers and mobile devices) to each other and the outside world via the internet. On a LAN, connectivity between network devices is delivered by a switch with ports connecting to other devices. Routers route packets between networks. The main types of network cabling are Ethernet twisted pair cabling or fiber optics. Currently, most mobile devices connect to a network wirelessly through an access point, which is connected to a switch/router via a cabled connection.
Telecommunications equipment is the hardware used to transmit voice and data to and from an organization. This equipment covers PBX (private branch exchange) equipment for call centers, leased/telephone lines, IP telephony, telephones, and mobile phones.
Facilities are buildings that house an organization’s IT infrastructure. Data centers also need electricity to power the servers, networking, and storage equipment, and to prevent overheating of equipment. Usually diesel generators are used as backup power sources. There can also be uninterruptable power supplies.