NIC Card Knowledge

A NIC card, or network interface card, is the electronic device which permits computers and computer devices to be connected together in a network. A NIC card works at both the OSI layer 1 (physical) and layer 2 (data link) layers since it provides the access to a networking medium while also being the conduit for communicating the MAC address at the lower-level addressing system. The NIC card acts as the relay or liaison for the computing machine to be able to send and receive network data through either a hard-wire or wireless network connection.

What Protocol or Language Do NIC Cards Use?

The majority of networks in use today use the Ethernet protocol which may sometimes be referred to as IEEE 802.3. Another protocol used in industry and academia is the Token Ring protocol. When using a computer on a network, the network interface card on each computer in the network must use the same protocol on the NIC card such as Ethernet or Token Ring. If you are purchasing a NIC card for home use, you can generally assume that retailers will be selling cards that are compatible with the Ethernet protocol unless otherwise annotated.

How Does a NIC Card Use a MAC Address?

A network interface card that is made to work with the Ethernet protocol will either be installed on a slot inside of your computer or plugged into your computer via USB or PCI slot connections. The NIC card will assign a Media Access Control (MAC) address to your computer based on the 48-bit serial number stored in the ROM on your card. Card vendors ensure that no two NIC cards have the same address by purchasing blocks of unique MAC addresses from the Institute of Electrical and Electronics Engineers (IEEE) and assign the addresses to the cards when built. When your computer is connected to a network, the MAC address is used to route network traffic to and from your computer.

How Do NIC Cards Connect to a Network?

NIC cards traditionally have been connected to a network via an Ethernet cable that plugs directly into the card and connects it to a network router, hub, or switch. The router, hub, or switch will then act as a relay between your computer’s NIC card and the network. As wireless networking technology has matured, the need to hardwire NIC cards has been eliminated when using wireless Ethernet cards. These cards have a small antenna built into the card that is used for communications with a central router, hub, or switch that is wireless enabled. The only requirements for a wireless enabled NIC card to communicate with a wireless router is to be using a compatible wireless technology standard and if security is enabled on the network to have the applicable security settings, passwords, etc entered on the client computer.