Network interface card

 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 that it can connect to a network. Modern NICs provide functionality to computers such as support for I/O interrupt, direct memory access (DMA) interfaces, data transmission, network traffic engineering  and partitioning.

A NIC provides a computer with a dedicated, full-time connection to a network by implementing the physical layer circuitry necessary for communicating with a data link layer standard, such as Ethernet or Wi-Fi. Each card represents a device and can prepare, transmit and control the flow of data on the network. The NIC uses the OSI model to send signals at the physical layer, transmit data packets at the network layer and operate as an interface at the TCP/IP layer.

The network card operates as a middleman between a computer and a data network. For example, when a user requests a web page, the computer will pass the request to the network card which converts it into electrical impulses. Those impulses are received by a web server on the internet and responds by sending the web page back to the network card as electrical signals. The card gets these signals and translates them into the data that the computer displays.

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Originally, network controllers were implemented as expansion cards that could be plugged into a computer port, router or USB device. However, more modern controllers are built directly into the computer motherboard chipset. Expansion card NICs can be purchased online or in retail stores if additional independent network connections are needed. When purchasing a NIC, specifications should correspond with the standard of the network.

The term network interface card is often considered interchangeable with the terms network interface controller, network adapter and LAN adapter.

Types of network interface cards

While the standard NIC is a plastic circuit board that slides into a computer to connect with the motherboard, there are multiple ways this connection can occur:

Wireless - These are NICs that use an antenna to provide wireless reception through radio frequency waves. Wireless NICs are designed for Wi-Fi connection.

Wired - These are NICs that have input jacks made for cables. The most popular wired LAN technology is Ethernet.

USB - These are NICs that provide network connections through a device plugged into the USB port.

Fiber optics - These are expensive and more complex NICs that are used as a high-speed support system for network traffic handling on server computers. This could also be accomplished by combining multiple NICs.

Components of network interface cards

Network interface card components include the following:

Speed - All NICs have a speed rating in terms of Mbps that suggests the general performance of the card when implemented in a computer network with ample bandwidth. If the bandwidth is lower than the NIC or multiple computers are connected with the same controller, this will slow down the labeled speed. The average Ethernet NICs are offered in 10 Mbps, 100 Mbps, 1000 Mbps and 1 Gbps varieties.

Driver - This is the required software that passes data between the computer's operating system (OS) and the NIC. When a NIC is installed on a computer, the corresponding driver software is also downloaded. Drivers must stay updated and uncorrupted to ensure optimal performance from the NIC.

MAC address - Unique, unchangeable MAC addresses, also known as a physical network address, are assigned to NICs that is used to deliver Ethernet packets to the computer.

Connectivity LED - Most NICs have an LED indicator integrated into the connector to notify the user of when the network is connected and data is being transmitted.

Router - A router is also sometimes needed to allow communication between a computer and other devices. In this case, the NIC connects to the router which is connected to the internet.

Serial Communication

In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.

Serial communication is used for all long-haul communication and most computer networks, where the cost of cable and synchronization difficulties make parallel communication impractical. Serial computer buses are becoming more common even at shorter distances, as improved signal integrity and transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity (no need for serializer and deserializer, or SerDes) and to outstrip its disadvantages (clock skew, interconnect density). The migration from PCI to PCI Express is an example.

                                PARALLEL COMMUNICATION

In data transmission, parallel communication is a method of conveying multiple binary digits (bits) simultaneously. It contrasts with serial communication, which conveys only a single bit at a time; this distinction is one way of characterizing a communications link.

The basic difference between a parallel and a serial communication channel is the number of electrical conductors used at the physical layer to convey bits. Parallel communication implies more than one such conductor. For example, an 8-bit parallel channel will convey eight bits (or a byte) simultaneously, whereas a serial channel would convey those same bits sequentially, one at a time. If both channels operated at the same clock speed, the parallel channel would be eight times faster. A parallel channel may have additional conductors for other signals, such as a clock signal to pace the flow of data, a signal to control the direction of data flow, and handshaking signals.

Parallel communication is and always has been widely used within integrated circuits, in peripheral buses, and in memory devices such as RAM. Computer system buses, on the other hand, have evolved over time: parallel communication was commonly used in earlier system buses, whereas serial communications are prevalent in modern computers.

Advantages

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Serial transmission 

It is cost-effective

It is appropriate for long-distance communication.

More reliable

Parallel transmission 

Transmits data at a higher speed.

Suits better for short-distance communication.

Set of bits are transferred simultaneously.

Disadvantages

Serial transmission 

Data transmission rate is low.

Throughput relies on the bit rate.

Parallel transmission 

It is a costly transmission system.

In order to transmit the data over long ranges, the thickness of the wire has to be increased to diminish signal degradation.

There are multiple communication channels required.

   DIFFERENCES BETWEEN SERIAL AND PARALLEL COMMUNICATION

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