What is the network card on the computer?

What is a network card?

A network card is a piece of computer hardware designed to allow computers to communicate on a computer network. Since it has a MAC address, it belongs to Layer 2 of the OSI model.

Network cards allow users to connect to each other via cable or wirelessly. Each network card has a unique 48-bit serial number called a MAC address, which is written in a ROM on the card. Every computer on the network must have a unique MAC address. No two network cards produced have the same address. This is because the Institute of Electrical and Electronics Engineers (IEEE) is responsible for assigning unique MAC addresses to network interface controller (network card) vendors.

Extended knowledge:

Function of network card:

1. Data encapsulation and decapsulation

When sending, the previous The data passed by the Ethernet layer is added with a header and a trailer to become an Ethernet frame. When receiving, the header and trailer of the Ethernet frame are stripped off, and then sent to the upper layer.

2. Link management

is mainly implemented through the CSMA/CD (Carrier Sense Multiple Access with Collision Detection, Carrier Sense Multiple Access with Collision Detection) protocol.

3. Data encoding and decoding

is Manchester encoding and decoding. Among them, Manchester code, also known as digital bidirectional code, phase code or phase encoding (PE), is one of the commonly used binary code line encoding methods. It is used by the physical layer to encode the clock and data of a synchronous bit stream.

In communication technology, a code used to represent the combination of data and timing signals in the bit stream to be sent. Commonly used in Ethernet communications, train bus control, industrial buses and other fields.

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