What Are Network Cards

Network cards, be it wired or wireless, in simple words, are readily-available, easy-to-install computer hardware components that are designed to allow a computer to communicate over a computer network. They are also referred to as network adapters, network interface cards, LAN adapters, or network interface controllers (NICs). Network cards can transfer data at the rate of 10, 100, or 1000 Megabits per second.

Usually there is a network card installed in every computer. An Ethernet cable is a must for preinstalled network cards. But wireless network cards need a wireless router for communication.

To get a better idea about network cards one needs to have a general understanding of OSI Model, the different layers in it, MAC addresses, network protocols, and Ethernet. Let me start with OSI first. Open Systems Interconnection (OSI) or OSI Reference Model is a loose description for layered communications and computer network protocol design. It divides the network architecture into different layers of similar functions. The layers thus divided are application, presentation, session, transport, network, data-link, and physical layers. Each layer provides services to the layer above it by receiving service from the layer below it.

A network card functions as both, a physical layer and a data-link layer by providing physical access to a networking medium and also provides a low-level addressing system through MAC addresses. This will help users to connect to each other with or without wires.

Do you know what MAC addresses are? MAC or Media Access Control address is an identifier assigned to network adapters by the manufacturer for the sake of identification. The three numbering spaces after a manufacturers name, like MAC-48, or EUI-64, are a few examples. Typically, a MAC address has a 48-bit network hardware identifier that is stored into a ROM chip and every Ethernet network card has this unique number.