What Is an Integrated Network Interface Controller?
A network interface controller handles all the network access functions for a computer. Originally this capability was sold as a separate component, which is why a NIC is now said to be "integrated." Contemporary computers usually have the NIC included on the motherboard.
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Names
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The network interface controller has many names. It was originally called a network interface card because it was sold on a separate circuit board, or card, that fitted into an expansion slot of a computer. Although most computers have an integrated NIC, the term network interface card is still used by many in the industry, as are the names "network card," "LAN card" and "Ethernet card," although none of them are actually on a card. The most common NIC is a "network adapter."
Responsibilities
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The NIC has two areas of responsibility. The first is to translate between computer data and electric pulses and back again. The second purpose of a NIC is to manage access to the wire of the network. This involves listening for silence on the wire before applying the signal because no two computers can apply data to the same cable at the same time. Electrical current runs the length of a wire in a fraction of a second, so if there are two signals on the cable at the same time, they interfere with each other and become meaningless. This is called collision. If collision does occur, the NIC waits a random length of time before listening to the wire again. This is designed to prevent all NICs on the network from hearing the same silence at exactly the same time.
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Media Access Control
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The part of the NIC that handles access to the cable is called the "medium access controller." The functions the medium access controller performs are summarized as "media access control," which is simply expressed as MAC.
MAC Address
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The MAC address is the physical address of the computer on the network. No computer can send or receive data over a network without a MAC address. Each medium access controller puts the MAC address of the destination computer on the front of all outgoing data, and it reads the address attached to all data on the cable to know when it is the intended recipient. The MAC address is actually the serial number of the network interface controller and is unique throughout the world.
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References
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