Network cards

If computers are combined into a network, for which a special cable is routed , then network cards are inserted into the expansion slot of the motherboard. The speed of data transmission over the network via network cards, depending on the type of technology used, is 10 Mb/s, 100 Mbps, 1 Gb/s and 10 Gbit/s.

Network cards have their own unique address, which uniquely identifies the address of the local computer on the network. Network cards convert the data coming to them from computers into special packets-frames, forward them to the recipient, i.e. other network cards, and are responsible for reliable delivery to the specified recipient via the network. Since the functions that the network cards perform are complex, they include a specialized processor, which provides high-speed hardware support for these functions. When choosing network cards, the main parameter is the network type, which will include local computers. Known standard types of local networks, such as FDDI (Fiber Distributed Data Interface), Ethernet (Ethernet, aether-ether), etc., are incompatible with each other, and each network card only supports a specific type of local area network.

Ethernet network cards have passed three generations in their development. Network cards of the first generation were made on discrete logic chips, which resulted in low reliability. They had a small buffer memory, which led to low performance. In addition, the configuration of the network card was done manually, using jumpers. For each type of network card, you used your driver, and the interface between the driver and the operating system was not standardized.

In second-generation network cards, chips with a high degree of integration are widely used, which increases reliability. In addition, the drivers for these cards are based on standard specifications. Network cards of the second generation usually come with drivers that work both in the standard NDIS, developed by 3Com and Microsoft and approved by IBM, and in the ODI standard developed by Novell.

Network cards of the third generation are based on specialized integrated circuits (ASIC), which improves performance and reliability while reducing costs. Increasing the performance of the network-to-memory channel is very important for improving the performance of the network as a whole, since the performance of a complex route, including, for example, hubs, switches, routers, global communication channels, etc., is always determined by the performance of the slowest element of this route. Therefore, if the network card of the server or client computer is slow, no fast switches can improve the network performance.

Today's network cards can be attributed to the fourth generation. They necessarily include ASIC, which performs the functions of MAC-level (English MAC-PHY), the speed is developed up to 1 Gbit/sec, and also there is a large number of high-level functions. The set of such functions can include the RMON remote monitoring agent, remote control of the computer, etc. In server versions of network cards, there is almost certainly a powerful processor that unloads the CPU.