- Ethernet The most widely used local area network (LAN) access method. Ethernet allows connection to a company or home network as well as to a cable modem or digital subscriber line (DSL) modem for Internet access. Today, almost all PCs and Macs come with 10/100 Ethernet ports, which connect internally to a network adapter (NIC) that is often built onto the motherboard. Ethernet can be added to older equipment by plugging a NIC into an empty PCI slot. Gigabit Ethernet is an Ethernet technology that raises transmission speed to 1 Gbps.
- Router A network device that forwards packets from one network to another. Based on internal routing tables, a router reads each incoming packet and decides how to forward it. Routers are also used to separate local area networks (LANs) into sub-networks in order to balance traffic within workgroups and filter traffic for security purposes. They can be used at the edge of the network to connect to remote offices or to an Internet service provider (ISP) for Internet access.
- Switch A mechanical or electronic device that directs the flow of electrical or optical signals from one side to the other. Switches with more than two ports, such as a LAN switch or PBX, are able to route traffic.
- Wireless LAN A local area network that transmits over the air typically in the 2.4GHz or 5GHz unlicensed frequency band. It does not require line of sight between sender and receiver. Wireless base stations (access points) are wired to an Ethernet network and transmit a radio frequency over an area of several hundred feet, through walls and other non-metal barriers. Roaming users can be handed off from one access point to another as they are when using a cellular phone system.
- Wi-Fi (WIreless-FIdelity) A logo from the Wi-Fi Alliance that certifies that Ethernet devices comply with the IEEE 802.11 wireless standard. In the early 2000s, Wi-Fi/802.11 became widely used.
- Wide Area Network (WAN) A communications network that covers a wide geographic area. A LAN (local area network) is contained within a building or complex, and a MAN (metropolitan area network) generally covers a city or suburb.
- Virtual Private Network (VPN) A private network that is configured within a public network (a carrier’s network or the Internet) in order to take advantage of the economies of scale and management facilities of large networks. VPNs are widely used by enterprises to create wide area networks (WANs) that span large geographic areas, to provide site-to-site connections to branch offices and to allow mobile users to dial up their company LANs.
- IP telephony The two-way transmission of voice over a packet-switched IP network. The terms IP telephony and voice over IP (VoIP) are synonymous. However, the term VoIP is widely used for the actual services offered, while IP telephony often refers to the technology behind it. In addition, IP telephony is an umbrella term for all real time applications over IP, including voice over instant messaging (IM) and videoconferencing.
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