A Network Interface Card (NIC) is a device that allows computers to be joined together in a network, typically a Local Area Network (LAN). Networked computers communicate with each other using a particular protocol or agreed-upon language for transmitting data packets between the different machines or "nodes." The network interface card acts as an interpreter, allowing the machine to both send and receive data on a LAN. Information Technology (IT) specialists often use these cards to setup wired or wireless networks. Show Function and Purpose of an NICOne of the most common languages or protocols used with a LAN is Ethernet. There are also other, lesser-used protocols such as Token Ring. When building a LAN, a network interface card is installed in each computer on the network and each one must use the same architecture. For example, all the cards must be Ethernet cards, Token Ring cards, or an alternate technology. The back of a network interface card features a port for an Ethernet cable.An Ethernet network interface card is installed in an available slot inside the computer, typically on the motherboard. The NIC assigns a unique Media Access Control (MAC) address to the machine, which is used to direct traffic between the computers on a network. Network cards also change data from a parallel format, used by computers, to a serial format necessary in data transfers; and then back again for received information. Wired NetworksA card's back plate features a port that fits a data cable, such as an Ethernet cable, which runs from each NIC to a central hub or switch. The hub acts like a relay, passing information between computers using their MAC addresses and allowing them to share resources like printers and scanners. In a wired network, a cable physically connects each computer to each other or to a hub. Wireless NetworksA network interface card does not have to be hard-wired with physical cable. Wireless cards are installed like their wired counterparts, but rather than a port for a cable, the card features a small antenna. The NIC communicates with a central wireless switch or hub via radio waves. Wireless LANs are often convenient, but may have some restrictions depending on the material a building is made from. For example, lead in walls can block wireless signals between the network interface card and a hub or switch. Choosing the Right NICWhen buying components for a LAN, it is important to make sure the NICs and hub or switch have the same capabilities. The entire network should be either wired or wireless, unless components are specifically chosen that have both functionalities. In addition, newer versions of hardware often support more features and greater data speeds than older equipment. It is important to make sure a central switch or hub is just as good as the individual cards used in a network. Wide Area Networks and NICsComputer users can also connect LANs located in different areas of a city, region, or country, through Asynchronous Transfer Mode (ATM) and the creation of a Wide Area Network (WAN). LANs are built with a network interface card in each computer, but ATM uses Internet connections to link multiple LANs to an online switch, making each one part of a network. This type of WAN is referred to as an "Internetwork," as the larger WAN consists of individual nodes that are each a smaller LAN. Most computers still allow users to directly plug in Ethernet cables to connect to the Internet."Network card" redirects here. For the British Rail discount card, see Network Railcard. Network interface controller
A network interface controller (NIC, also known as a network interface card,[3] network adapter, LAN adapter or physical network interface,[4] and by similar terms) is a computer hardware component that connects a computer to a computer network.[5] Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus. The low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard, or is contained into a USB-connected dongle. Modern network interface controllers offer advanced features such as interrupt and DMA interfaces to the host processors, support for multiple receive and transmit queues, partitioning into multiple logical interfaces, and on-controller network traffic processing such as the TCP offload engine. Purpose[edit]The network controller implements the electronic circuitry required to communicate using a specific physical layer and data link layer standard such as Ethernet or Wi-Fi.[a] This provides a base for a full network protocol stack, allowing communication among computers on the same local area network (LAN) and large-scale network communications through routable protocols, such as Internet Protocol (IP). The NIC allows computers to communicate over a computer network, either by using cables or wirelessly. The NIC is both a physical layer and data link layer device, as it provides physical access to a networking medium and, for IEEE 802 and similar networks, provides a low-level addressing system through the use of MAC addresses that are uniquely assigned to network interfaces. Implementation[edit]12 early ISA 8 bit and 16 bit PC network cards. The lower right-most card is an early wireless network card, and the central card with partial beige plastic cover is a PSTN modem. Network controllers were originally implemented as expansion cards that plugged into a computer bus. The low cost and ubiquity of the Ethernet standard means that most new computers have a network interface controller built into the motherboard. Newer server motherboards may have multiple network interfaces built-in. The Ethernet capabilities are either integrated into the motherboard chipset or implemented via a low-cost dedicated Ethernet chip. A separate network card is typically no longer required unless additional independent network connections are needed or some non-Ethernet type of network is used. A general trend in computer hardware is towards integrating the various components of systems on a chip, and this is also applied to network interface cards. An Ethernet network controller typically has an 8P8C socket where the network cable is connected. Older NICs also supplied BNC, or AUI connections. Ethernet network controllers typically support 10 Mbit/s Ethernet, 100 Mbit/s Ethernet, and 1000 Mbit/s Ethernet varieties. Such controllers are designated as 10/100/1000, meaning that they can support data rates of 10, 100 or 1000 Mbit/s. 10 Gigabit Ethernet NICs are also available, and, as of November 2014, are beginning to be available on computer motherboards.[6][7] A Qlogic QLE3442-CU SFP+ dual-port NIC Modular designs like SFP and SFP+ are highly popular, especially for fiber-optic communication. These define a standard receptacle for media-dependent transceivers, so users can easily adapt the network interface to their needs. LEDs adjacent to or integrated into the network connector inform the user of whether the network is connected, and when data activity occurs. The NIC may use one or more of the following techniques to indicate the availability of packets to transfer:
NICs may use one or more of the following techniques to transfer packet data:
Performance and advanced functionality[edit]Multiqueue NICs provide multiple transmit and receive queues, allowing packets received by the NIC to be assigned to one of its receive queues. The NIC may distribute incoming traffic between the receive queues using a hash function. Each receive queue is assigned to a separate interrupt; by routing each of those interrupts to different CPUs or CPU cores, processing of the interrupt requests triggered by the network traffic received by a single NIC can be distributed improving performance.[9][10] The hardware-based distribution of the interrupts, described above, is referred to as receive-side scaling (RSS).[11]: 82 Purely software implementations also exist, such as the receive packet steering (RPS) and receive flow steering (RFS).[9] Further performance improvements can be achieved by routing the interrupt requests to the CPUs or cores executing the applications that are the ultimate destinations for network packets that generated the interrupts. This technique improves Locality of reference and results in higher overall performance, reduced latency and better hardware utilization because of the higher utilization of CPU caches and fewer required context switches. Examples of such implementations are the RFS[9] and Intel Flow Director.[11]: 98, 99 [12][13][14] With multi-queue NICs, additional performance improvements can be achieved by distributing outgoing traffic among different transmit queues. By assigning different transmit queues to different CPUs or CPU cores, internal operating system contentions can be avoided. This approach is usually referred to as transmit packet steering (XPS).[9] Some products feature NIC partitioning (NPAR, also known as port partitioning) that uses SR-IOV virtualization to divide a single 10 Gigabit Ethernet NIC into multiple discrete virtual NICs with dedicated bandwidth, which are presented to the firmware and operating system as separate PCI device functions.[3][15] TCP offload engine is a technology used in some NICs to offload processing of the entire TCP/IP stack to the network controller. It is primarily used with high-speed network interfaces, such as Gigabit Ethernet and 10 Gigabit Ethernet, for which the processing overhead of the network stack becomes significant.[16] Some NICs offer integrated field-programmable gate arrays (FPGAs) for user-programmable processing of network traffic before it reaches the host computer, allowing for significantly reduced latencies in time-sensitive workloads.[17] Moreover, some NICs offer complete low-latency TCP/IP stacks running on integrated FPGAs in combination with userspace libraries that intercept networking operations usually performed by the operating system kernel; Solarflare's open-source OpenOnload network stack that runs on Linux is an example. This kind of functionality is usually referred to as user-level networking.[18][19][20] See also[edit]
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What card is used to connect a computer to a network?What is a network interface card (NIC)? A network interface card (NIC) is a hardware component, typically a circuit board or chip, which is installed on a computer so it can connect to a network.
Which is the most commonly used network card in computer?Ethernet Network card is the most commonly used network card.
What are network interface cards?A network interface card (NIC) is a hardware component without which a computer cannot be connected over a network. It is a circuit board installed in a computer that provides a dedicated network connection to the computer. It is also called network interface controller, network adapter or LAN adapter.
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