Network Interface Card

NIC Stands for Network Interface Card.  It is one of the most important computer network devices that are used for the data communication and to connect the computers with each other.  It is plugged inside the computer either in the PCI slot or it is built-in the motherboard.

A twisted pair UTP/STP with RJ45 connector is used to connect the computer with the Hub or Switch. Fiber optic cable can also be used to connect the computer with the hub or switch.
A NIC can be wired or wireless and it has digital circuitry and microprocessor.  A wireless NIC is used to connect the computers with each other wirelessly. There are different vendors of the NIC such as D-Link, 3Com, Intel, Realtek, Baylan and Baynet.

Before buying and installing a network interface card in your computer make sure that it is compatible with the other network devices.  NIC card operates on the Data Link and physical layer of the OSI layers model.
For every computer in a network, it is required to have a NIC to communicate with other computers.

Implementation

Whereas network controllers used to operate on expansion cards that plugged into a computer bus, the low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard. Newer server motherboards may even have dual network interfaces built-in. The Ethernet capabilities are either integrated into the motherboard chipset or implemented via a low-cost dedicated Ethernet chip, connected through the PCI (or the newer PCI express) bus. A separate network card is not required unless additional interfaces are needed or some other type of network is used.

The NIC may use one or more of two techniques to indicate the availability of packets to transfer:

• Polling is where the CPU examines the status of the peripheral under program control.
• Interrupt-driven I/O is where the peripheral alerts the CPU that it is ready to transfer data.

and may use one or more of two techniques to transfer packet data:

• Programmed input/output is where the CPU moves the data to or from the designated peripheral to memory.
• Direct memory access is where an intelligent peripheral assumes control of the system bus to access memory directly. This removes load from the CPU but requires more logic on the card. In addition, a packet buffer on the NIC may not be required and latency can be reduced.

An Ethernet network controller typically has an 8P8C socket where the network cable is connected. Older NICs also supplied BNC, or AUI connections. A few LEDs inform the user of whether the network is active, and whether or not data transmission occurs. Ethernet network controllers typically support 10 Mbit/s Ethernet, 100 Mbit/s Ethernet, and 1000 Mbit/s Ethernet varieties. Such controllers are designated 10/100/1000 - this means they can support a notional maximum transfer rate of 10, 100 or 1000 Megabits per second.

Every NIC has unique MAC address and no two NIC cards from two different vendors can have the same MAC address.  NIC has twisted pair, BNC and AUI sockets.  The one end of the network cable is used to connect with the NIC and the other end is used to connect with the hub or switch.

NIC provides the fulltime connectivity for the data transmission.  Sometimes computers do not communicate with each other due to the malfunctioning of the NIC.

The network interface cards problems can be resolved with the following tips.

• Make sure that you have the updated and correct version of the LAN card’s driver.
• Ensure that the LEDs of the NIC are working properly.
• Check that the network cable is properly connected at both ends.
• Right click on the network status icon on the right bottom of the desktop and click repair.
• Ensure that the TCP/IP settings are accurate.
• Disable the antivirus and firewall.
• If the problem still persists then try to replace the NIC with a new one.
• Hub or a switch in a computer network acts as a relay that passes the information from one computer to another.  It is important that the LAN card is compatible with the hub or switch to make the data flow faster to avoid the packet loss and network congestion.