NIC (Network interface card)

NIC (Network interface card)

NIC allows a computer to send and receive data across a network, NIC provides an interface between a data bus (a pathway inside a computer that carries data between hardware components) and network medium. Every NIC has Media Access Control (MAC) address, which is a unique binary address. This MAC address is used to identify each node on a network. NIC is integrated into a motherboard.

Working Principal of NIC

NIC links a computer with the network cabling system. NIC fits into one of the expansion slots available in the motherboard of a computer. The network cabling. The network cabling medium is connected through the ports available in the NIC.

NIC also contain driver which relies at the MAC sub-layer of the data link layer of the OSI model. Also the NIC read only memory (ROM) function as the logical link control (LLC0 sub-layer.

NIC and its accompanying software and firmware (coded instructions that are stored permanently in ROM) perform the following roles:

  • Prepares data for the transmission medium
  • Sends data
  • Control data flow


Preparing data for the transmission medium

Data is transmitted over a network one bit at a time, means serial transmission is made through the networking media. On the other hand, parallel transmission takes place for data travelling between CPU and NIC. Therefore, the major responsibility of NIC is to commute this parallel data into serial one by which it can be transmitted over the network.


Sending Data

Another functionality of NIC is to control data over the network with the help of data flow control. NIC uses media-access technique such as CSMA/CD for accessing the transmission medium.

Controlling Data Flow

Another functionality of NIC is to data flow. NIC follow some transmission rules for transmitting data between two computers. NIC hold the transmission speed as well as time interval before transmitting data.


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