Function

• In order for a network to work, each computer and server must have a NIC installed. The NIC allows cables, usually fiber optic, to transfer information between the computers. Most desktop PCs have a NIC installed on the motherboard, or an integrated NIC. If not, a NIC can be added to an available slot.
  
  

Purpose

• NICs are a way for multiple computers to share information between each other. When they are connected to a network, data moves using the PCI's bus system. The data travels in parallel although the network needs a serial transmission. The NIC has a transceiver that coverts parallel to serial and vice versa.
  
  

MAC

• NICs also have a media access control (MAC) which contains source addresses by the manufacturer. The addresses are assigned in blocks of eight or 16 and have enough variation so that no two NICs have the same address on the network. The address ensures that the computer is unique and can move data to and from other computers without confusion. MAC addresses are stored on a ROM chip on the NIC.
  
  

LAN

• Local Area Network (LAN) is the most common type of data network. LAN networks are usually small, connecting a roomful or a floor of computers together, but can be large enough to network computers miles apart. Businesses, companies, universities, and offices usually utilize LAN networks. LANs connected through nodes like bridges, switches and repeaters, can form larger LANs. Computers on a LAN can share information between each other, and when a computer is connected through a router, it may have access to a metropolitan area network (MAN) or a wide area network (WAN).
  
  

Ethernet

• Ethernet is a system developed by Xerox Corporation's Palo Alto Research Center. Ethernet is a standard created by the Institute of Electrical and Electronic Engineers (IEEE) and is one of the IEEE 802 standards, speficially IEEE 802.3. This standard is accepted worldwide and is probably the most used LAN technology. In a LAN configuration, computers attach to the LAN through transceivers or NICs.