What Is the Function of a Network Interface Card?

The primary function of a network interface card (NIC) is to provide a physical link to a computer network. This connection allows computers to communicate with servers, as well as other computers on the network. Each NIC has a unique serial number, which is called a MAC address. Every computer connected to the network is required to have a unique MAC address that is stored on the network interface card. If you are building a home network or utilizing broadband Web access, your NIC connects you to the outside world.

Facts

Newer computers have the network interface card integrated into the motherboard of the computer. On older models, the NIC is typically installed in the Peripheral Component Interconnect (PCI) slot. Some older computer also have an external network interface card that is attached to a USB port. NICs that are hardwired into the motherboard can be found on the side or back of your computer. Look for the Ethernet port, which looks like a large telephone jack. Usually blinking lights just above the port will indicate activity on the network.

Currently, there are three types of cards on the market , each with a width of 54.0 mm and a length of 85.6 mm. The difference is in the thickness of the cards: Type 1 is 3.3 mm; Type 2 is 5.0 mm; and Type 3 has a thickness of 10.5 mm.

Connection Types

Network interface cards are either wired (LAN) or wireless. Both NICs are generally compatible with Windows and other operating popular systems. Most NICs use network drivers, which are computer programs that allow software applications to communicate with network hardware. The necessary drivers are usually integrated into the computer system. The drivers usually installs automatically when the hardware is turned on. Another kind of network connection is called virtual private networks (VPN). VPNs are essentially software applications that use a public network, such as the Internet, to link computers together.

PCI

A PCI network interface card is part of the internal components in most personal computers. Also called a PCI bus, it works by linking to the network through the system bus (the fastest bus) and functions as a bridge to route traffic through the system. The PCI, like many devices, is plug and play (PnP). This simply means you plug the hardware into the PCI slot and the computer's wizard typically guides you through the rest of the installation process. As long as the NCI is compatible with your system you can be up and running in a short amount of time.

PCIs are most often used when setting up local area networks (LAN). LANs are the most widely used data networks. In most cases, LANs are used to service a local area such as the floor of an office building or computer networks on college campuses or industrial facilities.

PCMIA

The network interface card typically used in laptops is called a personal computer memory card (PCMCIA). It's a very thin hardware that fits into one of the two PCMCIA slots typical located on most notebook computers.Wireless network interface cards (WNIC) are used to set up a wireless LAN.) Each computer on the network requires a wireless NIC that fits directly into an expansion slot on the computer.

After each computer on the network has the appropriate cards and other devices installed, users will have the ability to share files, printers and applications. They will also have access to a broadband Web connection, without having to run Ethernet cable connections.

VPN

A VPN uses public telecommunications networks to conduct private data communications. Most VPN implementations use the Internet as the public infrastructure and a variety of specialized protocols to support private communications through the Internet. One of the primary advantages to virtual private networks is the lower cost compared to the other available options.

Other Considerations

One thing you will want to keep in mind when buying network interface cards is the speed you will require. Conventional NICs support 10 megabits per second. If you want faster connections, you can purchase network interface cards that function at speeds up to 10 or 20 gigabits per second. Also, your system standards and the type of ports they have is information you'll need to consider. Some of the more popular interfaces are: PCI, PCI-x, PCI-e and USB.

You should also consider having your network communication card capable of supporting half-duplex and full-duplex functions. A half-duplex operation transmits or receives information in a single transaction. Full-duplex operations can send and receive data at the same time, which ultimately increases the speed of your network.

References

• Upgrading and Repairing PCs; Scott Mueller, 2007