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Network Interface Card (NIC) and Wireless Network Interface Card (WNIC)


Here are the links to wikipedia for: NIC and WNIC


What is a NIC?

    A network interface card, or NIC, is a device that allows computers to be joined together in a LAN or WAN. Generally, NICs were implemented as expansion cards that plug into a computer bus to give a computer system an added or new computing ability (similar to adding a graphics card into a computer for improved visual effects). Nowadays, due to improved technology and low cost, the network interface is built directly into the main board or motherboard of a computer or server. Networked computers communicate with each other using a given protocol or some degree of agreed-upon language for transmitting data packets between the different machines/computers, known as nodes, which are essentially connection points. The network interface card's main role is to act as a liaison for computers to both send and receive data on the their LAN. The most common language protocol for wired networks is ethernet, sometimes referred to as IEEE 802.3, that is an architecture developed by Xerox Corporation in 1976. The ethernet basically supports separate types of data transfer rates that can be implemented between various systems.

    Sometimes you may also find a lesser-used protocol known as a token ring that all the computers (in a LAN) are connected to in a ring and information is sent in such a way to prevent collision and redundancy. When establishing a LAN, a NIC must be placed in each machine and all NICs must be of the same architecture; either ethernet, a token ring, or some other alternative that will provide the transfer of data. The NIC assigns a 48-bit serial number called a MAC (media access control) address which is used to direct traffic between the machines in a LAN. The port of the NIC resembles that of a phone jack but is somewhat larger and thicker, this is used to support the ethernet, and is able to transfer large amounts of information.

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                                                                                                                                                Image sourced from wikipedia: http://en.wikipedia.org/wiki/File:Network_card.jpg

                                                                                                             




Application:

    The ethernet is used to transfer and receive data along wires which support 10 Mbit/s ethernet, 100 Mbit/s ethernet, and 1000 Mbit/s ethernet varieties (speeds). Such controllers are designated 10/100/1000- this means they can support a notional maximum transfer rate of 10, 100 or 1000 Megabits per second.

As depicted from Wikipedia from NIC webpage, the NIC may use one or more of four techniques to transfer data.
  • Programmed I/O where the microprocessor alerts the designated peripheral by applying its address systesms to address bus.
  • interrupt-driven I/O where the peripheral alerts the microprocessor that it is ready to transfer data.
  • Polling where the central processing unit (CPU) examines the statues of peripheral under program control.
  • Direct memory access where a peripheral assumes control of the system bus to access the memory directly.


What is a WNIC?

    A wireless network interface card is similar to the NIC but instead of using a wired interface such as ethernet, it uses radio-based networking to transfer and receive data. The card uses antenna to communicate through microwaves, a type of radio waved commonly used for information sharing through circuitry. The network card is commonly connected using a PCI bus with one or more antenna sticking out but may also be connected to a USB port as an adapter. The WNIC operates on the IEEE 802.11 standard for wireless operations and networking.

    Each standard is only capable of communicating with similar standards or earlier variants i.e. earlier interfaces usually only compatible with early variants while newer variants cover the new variation plus all previous variations before it. Wireless data transfer rates are measured in Mbits/s and wireless transmit power measures in dBm. In home and business networks the WNIC communicates through a router which is a portable device that forwards packets of data from computer networks or modems.

Types:



802.11 network standards
802.11
protocol
ReleaseFreq.
(GHz)
Bandwidth
(MHz)
Data rate per stream
(Mbit/s)
Allowable
MIMOstreams
ModulationApproximate indoor rangeApproximate outdoor range
(m)(ft)(m)(ft)
Jun 19972.4201, 21DSSSFHSS2066100330
aSep 19995206, 9, 12, 18, 24, 36, 48, 541OFDM35115120390
3.75,00016,000
bSep 19992.4205.5, 111DSSS38125140460
gJun 20032.4206, 9, 12, 18, 24, 36, 48, 541OFDMDSSS38125140460
nOct 20092.4/5207.2, 14.4, 21.7, 28.9, 43.3, 57.8, 65, 72.24OFDM70230250820
4015, 30, 45, 60, 90, 120, 135, 1507023025082
Table sourced from Wikipedia at http://en.wikipedia.org/wiki/IEEE_802.11

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Image sourced from Pace University: http://webpage.pace.edu/ms16182p/networking/wirelessdevices.html




Why Does This Matter?

    Network interface cards and wireless network interface cards are the strong essence of communication in the modern digital era. These allow the technological world to communicate from the comfort of peoples desks as well as allow for information sharing in the ultimate form of the Internet and World Wide Web. The use of WiFi also improves the use of wireless networking as people can easily access the Internet from laptops and mobile devices.
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