A Network Interface Card (NIC) is a hardware component that allows a computer to connect to a network. It is also known as a network interface controller, network adapter, LAN adapter, or Ethernet card. A NIC provides a dedicated, full-time connection to a network and implements the physical layer circuitry necessary for communicating with a data link layer standard, such as Ethernet or Wi-Fi. It allows computers to communicate over a computer network, either by using cables or wirelessly. NICs are both a physical layer and data link layer device, as they provide physical access to a networking medium and, for IEEE 802 and similar networks, provide a low-level addressing system through the use of MAC addresses that are uniquely assigned to network interfaces.
NICs are typically installed on a computer as a circuit board or chip. They can be internal or external. Internal NICs are installed in a computers motherboard and require network cables to provide network access. They are of two types: Peripheral Component Interconnect (PCI) connection and Industry Standard Architecture (ISA) . External NICs are used in desktops and laptops that do not have an internal NIC. They are of two types: wireless and USB-based.
NICs provide functionality to computers, such as support for I/O interrupt, direct memory access (DMA) interfaces, data transmission, network traffic engineering, and partitioning. They use the OSI model to send signals at the physical layer, transmit data packets at the network layer, and operate as an interface at the TCP/IP layer. Each card represents a device and can prepare, transmit, and control the flow of data on the network.
In summary, a NIC is a hardware component that allows a computer to connect to a network, providing a dedicated, full-time connection to the network and implementing the physical layer circuitry necessary for communicating with a data link layer standard. NICs can be internal or external and provide functionality to computers, such as support for I/O interrupt, direct memory access (DMA) interfaces, data transmission, network traffic engineering, and partitioning.
