A network adapter, also known as a network interface card, is a computer hardware device that allows network connections. Network cards are widely used, and there are many different types on the market, such as PCIe network cards, server network cards. This article will be the basis of the network card, functions, components and types of a full - range explanation.

What is a network card?
Before introducing the formal definition of a network card, it is important to understand the other names of network cards. There are many names for network adapters, such as network interface controller, network interface card, Ethernet card, local area network adapter, network adapter, or network adapter card. Despite their different names, they all refer to the circuit boards that enable networking devices such as computers and servers to connect to each other. In addition to built-in network cards, which are common in most computers and some network servers, you can plug things like a server card into an expansion slot on your device.

Functions of network card
The definition of network card is very simple, but what are the specific functions? As an interface at the TCP/IP layer, a NIC can transmit signals at the physical layer and packets at the network layer. Regardless of the layer, it acts as an intermediary between the computer or server and the data network. When a user sends a Web page request, the network card retrieves data from the user device and sends it to the network server, which then receives the required data for presentation to the user.

Construction of network card
The network card is generally composed of a controller, a boot ROM slot, one/more network card ports, a motherboard interface, LED indicators, a bracket and some other electronic components, each of which has its own unique functions:

Controller: The controller acts like a tiny CPU and processes the data it receives. As the core part of network adapter, controller directly determines the performance of network adapter.

Boot ROM slot: This slot on the NIC enables the Boot ROM function. Boot ROM enables disk-free workstations to connect to the network, improving security and reducing hardware cost.

Nic port: Normally, this port is directly connected to an Ethernet cable or optical module to generate and receive electrical signals from network cables or optical fiber jumpers.

Bus interface: This interface is located on one side of the circuit board and connects the network card to the computer or server by inserting an expansion slot.

LED indicator: The indicator helps users identify the working status of the network adapter, confirm whether the network is connected, and whether data is transmitted.

Stent: There are two types of stent on the market, one is a full-height stent with a full length of 12cm, and the other is a half-height stent with a length of 8cm. This bracket helps users attach the network card to an expansion slot in a computer or server.

Types of nics
Network adapters can be classified into the following types according to the host interface, transmission speed, and application domain.

Classification based on network connection mode
Based on the network card access mode, the network card can be divided into wired network card and wireless network card. As the name implies, wired network cards usually require a jumper (such as Ethernet jumper and fiber jumper) to connect a node to the network; A wireless card usually has a small antenna that uses radio waves to communicate with the access point to access the wireless network.

Classification based on bus interface type
ISA Bus network adapter: The ISA bus was released in 1981 and is an IBM standards-compliant bus architecture. Due to the slow speed of the 9Mbps network card, the ISA bus interface was gradually phased out and is now rare in the market.

PCI Bus network adapter: PCI was released in the 1890s to replace the previous ISA standard. It has a fixed width of 32 bits (data transfer rate 133MB/s) and 64 bits (data transfer rate 266MB/s). This type of network card was first used in servers, and more recently, in computers. Most computers today have embedded network cards instead of expansion cards. Therefore, the PCI bus network card has been replaced by other bus interfaces, such as PCI-X or USB interfaces.

Pci-x network adapter: PCI-X is an enhanced PCI bus technology. It supports 64-bit running up to 1064MB/s. In most cases, PCI-X slots are backward compatible with PCI nics.

PCIe card: PCIe is a recent standard popular on computer and server motherboards. PCIe cards are now available in five versions, each supporting different speeds.

USB card: The USB bus is an external bus standard. It comes in three versions with different transmission rates and can work with a variety of devices.

Classification by interface type
There are four types of network adapter ports on the market, depending on the connection wire. Rj-45 ports are used to connect twisted pair cables (such as Cat5 and Cat6), AUI ports are used to connect thick coaxial cables (such as AUI cables), BNC ports are used to connect thin coaxial cables (such as BNC cables), and optical ports are used to connect modules (such as 10G/25G optical modules).

Classification based on transmission speed
Depending on the speed, there are 10Mbps, 100Mbps, 10/100Mbps adaptive cards, 1000Mbps, 10G, 25G or even higher speed cards. The 10Mbps, 100Mbps, and 10/100Mbps adaptive nics are suitable for small Lans, homes, or offices. A 1000Mbps network card provides higher bandwidth for fast Ethernet. 10Gb/25Gb network cards and higher speed network cards are popular with large enterprises and data centers.

Classification based on application domain
Computer Network card: Most new computers now have a built-in network card in the motherboard, so there is no need for a separate LAN card. It typically has speeds of 10/100 MBPS and 1Gbps, and allows one PC to communicate with other PCS or networks.

Server NIC: The main function of the server NIC is to manage and process network traffic. Compared with the ordinary computer network card, the server network card requires higher data transmission speed, such as 10G, 25G, 40G or even 100G. In addition, the CPU usage of the server network card is very low because it has a special network controller that can lighten the CPU burden. To meet users' different requirements for server NIC speed, Fast Speed (FS) has introduced 10G PCIe nics and 25G/40G nics, which use Intel controllers and support optimization for multi-core processors and server and network virtualization.

conclusion
The performance of a network card directly affects the data transfer rate of the entire network, so whether you are looking for a home network card or choosing a server network card for a small business or data center, it is important to know what a network card is, its components and functions, and the type of network card before purchasing one.

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