Computer Network Assignment A134740 & A134455

1. BACKGROUND
Network Access Control (NAC) is a computer networking solution that uses a set of protocols to define and implement a policy that describes how to secure access to network nodes by devices when they initially attempt to access the network.[citation needed] NAC might integrate the automatic remediation process (fixing non-compliant nodes before allowing access) into the network systems, allowing the network infrastructure such as routers, switches and firewalls to work together with back office servers and end user computing equipment to ensure the information system is operating securely before interoperability is allowed.

Network Access Control aims to do exactly what the name implies—control access to a network with policies, including pre-admission endpoint security policy checks and post-admission controls over where users and devices can go on a network and what they can do.

"NAC's roots trace back to the trusted computing movement. In this context an open-architecture was created as an alternative to proprietary NAC initiatives. TNC-WG aims at enabling network operators to provide endpoint integrity at every network connection, thus enabling interoperability among multi-vendor network endpoints."[3]

Initially 802.1X was also thought of as NAC. Some still consider 802.1X as the most simple form of NAC, but most people think of NAC as something more.

2. BENEFITS
Technically speaking networking can be defined as a bunch of computers that have with wires running in between them. If proper implementation of a network is done it acts as a system that provides unique capabilities, to its users. These are much beyond the abilities of individual machines and software applications associated with them. The benefits networking offers to its users can be separated into two main groups i.e. sharing and connectivity. Networks make computers and their users capable of being connected together. This facilitates sharing of resources and information between the users. The modern businesses are expanded all over the world. So, uses and significance of networking has gained momentum during the last years.

2. WHAT IS NETWORK CLASSIFICATIONS
The following list presents categories used for classifying networks.

[edit]Connection method
Computer networks can be classified according to the hardware and software technology that is used to interconnect the individual devices in the network, such as optical fiber, Ethernet, wireless LAN,HomePNA, power line communication or G.hn.

Ethernet uses physical wiring to connect devices. Frequently deployed devices include hubs, switches, bridges, or routers. Wireless LAN technology is designed to connect devices without wiring. These devices use radio waves or infrared signals as a transmission medium. ITU-T G.hn technology uses existing home wiring (coaxial cable, phone lines and power lines) to create a high-speed (up to 1 Gigabit/s) local area network.

[edit]Wired technologies

 * Twisted pair wire is the most widely used medium for telecommunication. Twisted-pair wires are ordinary telephone wires which consist of two insulated copper wires twisted into pairs and are used for both voice and data transmission. The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. The transmission speed ranges from 2 million bits per second to 100 million bits per second.
 * Coaxial cable is widely used for cable television systems, office buildings, and other worksites for local area networks. The cables consist of copper or aluminum wire wrapped with insulating layer typically of a flexible material with a high dielectric constant, all of which are surrounded by a conductive layer. The layers of insulation help minimize interference and distortion. Transmission speed range from 200 million to more than 500 million bits per second.
 * Optical fiber cable consists of one or more filaments of glass fiber wrapped in protective layers. It transmits light which can travel over extended distances. Fiber-optic cables are not affected by electromagnetic radiation. Transmission speed may reach trillions of bits per second. The transmission speed of fiber optics is hundreds of times faster than for coaxial cables and thousands of times faster than a twisted-pair wire.[citation needed]

[edit]Wireless technologies

 * Terrestrial microwave – Terrestrial microwaves use Earth-based transmitter and receiver. The equipment look similar to satellite dishes. Terrestrial microwaves use low-gigahertz range, which limits all communications to line-of-sight. Path between relay stations spaced approx, 30 miles apart. Microwave antennas are usually placed on top of buildings, towers, hills, and mountain peaks.
 * Communications satellites – The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically 22,000 miles (for geosynchronous satellites) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
 * Cellular and PCS systems – Use several radio communications technologies. The systems are divided to different geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
 * Wireless LANs – Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. An example of open-standards wireless radio-wave technology is IEEE.
 * Infrared communication, which can transmit signals between devices within small distances not more than 10 meters peer to peer or ( face to face ) without any body in the line of transmitting.

Local area network
A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards like ITU-T G.hn also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines).[2] Typical library network, in a branching tree topology and controlled access to resources All interconnected devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbit/s Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers.

The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate. IEEE has projects investigating the standardization of 40 and 100 Gbit/s.[3]

4. BASIC HARDWARE COMPONENTS
Hardware comprises all of the physical part of the computer such as Monitor, CPU, motherboard, ram, CD-Rom, printer, scanner, hard disk, flash drive (AKA pen drive), processor, pci buses, floppy disk, power supply, VGA card, sound card, network interface card, peripherals, joystick, mouse, keyboard, foot pedal, computer fan, camera, headset and others.

On the other hard software is a logical part of a computer and is used to carry out the instructions, storing, executing and developing other software programs. A typical PC consists of a case or chassis in the desktop or tower case and these components.

5. CONCLUSION
The Computer today, is far greater than what it was back twenty years ago. Computers have changed society in a beneficial way. Today millions of people use computers at work and at home, due to the fact that they cost a third as much as what they used to. I have heard that one out of every four homes has a computer. For the reason they are so versatile. Computers now days can help you do anything from typing a basic letter, to running a multi-million dollar business. Computer’s size is another thing that has changed. The computer used to take up a whole classroom but now takes up about four-squared feet. Therefore, as you can see computers have changes every aspect of society today.

6. REFERENCES
www.wikipedia.my

http://www.exampleessays.com/essay_search/Conclusion_Computer.html

www.google.my