NICs (Network Interface Card) is an electronic device that is made on a PCB board that will convert signals so that a workstation can send and receive data on the network. Often referred to as an Ethernet card, or often also called a LAN card. A NIC is a network card that is installed in an expansion slot on a computer. The required slot can be either a PCI or an ISA slot. In addition, there are also several cards that are specifically designed for laptops or notebooks with PCMCIA sockets. As for the output port, it can be a BNC port, AUI (Thick Ethernet), and UTP.
Images: (1) PC NIC and (2) Laptop NIC
NICs (Network Interface Card) has a special address called an ethernet address or MAC address. This address is a 48-bit hex code. Each NIC has a different address. When a computer wants to communicate with other computers then it will emit a signal to find the address of the NIC in question. If the address has been found, then communication between the two ethernet cards can be done. If the destination NIC turns out to be handling communication with another ethernet card, a data collision or collision occurs. Both will then stop transmitting the signal, waiting to retransmit the signal at a random time, so that they can then communicate again.
NIC function (Network Interface Card)
NIC is used as a means of receiving and transmitting data over a network cable. The duties of the NIC are as follows:
- Transfer data to another computer by first preparing data from the computer so that it can be passed to the connecting media.
- Controls the flow of data between computers and cabling systems.
- Receives data transferred from another computer via cable and translates it into bits that the computer understands.
NIC Working Principle
NIC works at the physical layer, where data is broken down into bits and then sent over the network to other computers which are then assembled back into whole data. Each NIC has its own unique code, meaning that there is only one, consisting of a 12-digit code called the MAC Address (Media Access Control). The purpose of the MAC address is to avoid collisions between data on the network. For example, the node will send a data packet, then previously it will see whether the network is sending data packets or not. If the node sees that the network is not sending data packets, then the node will send data packets.
If a data packet is transmitted when the node is sending a data packet, a collision will occur. If a collision occurs, the node and the network will stop simultaneously to send data packets. After stopping, the node and the network will wait a random time to send data packets. Data packets that experience a collision will be sent back when there is an opportunity. This way of working is often called the CSMA/CD (Carrier Sence Multiple Access/Collison Detection) method, which is the management of simultaneous data transmission by computers/nodes.