NIC

A NIC, or network interface card, is a hardware component that provides a computer with a dedicated network connection. A NIC can be integrated on the motherboard or installed as an expansion card in a desktop, server, or other device. It serves as the interface between the host system and a data communication network, handling the physical layer and data-link layer responsibilities and attaching to the network medium via connectors such as an RJ-45 copper Ethernet port or a fiber optic interface.

A NIC encapsulates data into frames, manages addressing via a unique media access control (MAC) address, handles flow control, and provides the interface for higher-layer protocols to send and receive data. Modern NICs rely on drivers and firmware and can support features such as offloading of certain processing tasks, interrupt coalescing, jumbo frames, VLAN tagging, and energy management. They connect to a computer through buses such as PCIe, and in laptops or compact systems, via PCIe or USB.

Wired NICs use Ethernet standards, commonly supporting 10/100/1000 Mbps and faster variants, with higher-end models offering 10, 25, 40, or 100 gigabits per second and fiber-based interfaces such as SFP or SFP+ for higher density and distance. Wireless NICs, or Wi‑Fi adapters, provide wireless connectivity to a local area network and support 802.11 standards through USB, PCIe, or integrated interfaces.

Virtual NICs provide network interfaces to virtual machines and containers. They can be implemented in software or mapped to physical NICs using virtualization technologies such as VLANs or SR-IOV to enable multiple isolated networks from a single hardware device.

NICs are essential components in desktops, servers, and data centers, enabling network access, traffic management, and performance optimization through hardware features and driver support.