A network interface card (NIC), also known as a network adapter or LAN adapter, is a hardware component that allows computers to connect to a local area network (LAN) and communicate with other devices on the network. The NIC serves as the interface between the computer's internal bus (such as PCI or PCIe) and the network cable, facilitating the transmission and reception of data over the network.
Some features and functions of a network interface card include:
Physical connection: NICs typically have one or more ports for connecting network cables. The most common types of ports include Ethernet ports (RJ-45) for wired connections and wireless NICs that use radio signals for wireless connections.
Data link layer: The NIC operates at the data link layer (layer 2) of the open systems interconnection model. It is responsible for framing data into packets, adding addressing information (MAC addresses), and handling error detection and correction.
MAC address: Each NIC has a unique media access control (MAC) address, which is a hardware address assigned to the device. MAC addresses are used for identifying devices on a network.
Driver software: To enable communication between the NIC and the operating system, driver software is required. Operating systems come with built-in drivers for many common NICs, and additional drivers can be installed for compatibility with specific hardware.
Speed and duplex settings: NICs support different data transfer speeds, such as 10/100/1000 Mbps (megabits per second) or even higher for modern Gigabit and 10 Gigabit Ethernet standards. NICs may also support full-duplex or half-duplex communication.
Bus interface: NICs are designed to connect to a computer's internal bus, such as Peripheral Component Interconnect (PCI), PCI Express (PCIe), or USB, depending on the type of NIC and the computer's architecture.
Wireless NICs: In addition to wired NICs, there are wireless NICs that enable computers to connect to Wi-Fi networks. These wireless adapters use radio frequencies for communication instead of physical cables.
NICs are essential components for networking and enable computers to participate in local area networks, wide area networks, or the internet. They play a critical role in facilitating the exchange of data between devices within a network.