Networking Cables

Networking Cables

By Unknown   21:46   1 comment:

Networking cables are used to connect one network device to other network devices or to connect two or more computers to share printer, scanner etc. Different types of network cables like Coaxial cable, Optical fiber cable, Twisted Pair cables are used depending on the network's topology, protocol and size. The devices can be separated by a few meters (e.g. via Ethernet) or nearly unlimited distances (e.g. via the interconnections of the Internet).

While wireless may be the wave of the future, most computer networks today still utilize cables to transfer signals from one point to another.

                    

Twisted pair

Twisted pair cabling is a form of wiring in which pairs of wires (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling outelectromagnetic interference (EMI) from other wire pairs and from external sources. This type of cable is used for home and corporate Ethernet networks.

There are two types of twisted pair cables: shielded, unshielded.

Fiber Optic cable

An optical fiber cable consists of a center glass core surrounded by several layers of protective material. The outer insulating jacket is made of Teflon or PVC to prevent interference. It is expensive but has higher bandwidth and can transmit data over longer distances.

Coaxial cable

Coaxial lines confine the electromagnetic wave to area inside the cable, between the center conductor and the shield. The transmission of energy in the line occurs totally through the dielectric inside the cable between the conductors. Coaxial lines can therefore be bent and twisted (subject to limits) without negative effects, and they can be strapped to conductive supports without inducing unwanted currents in them and though.

The most common use for coaxial cables is for television and other signals with bandwidth of multiple megahertz. Although in most homes coaxial cables have been installed for transmission of TV signals, new technologies (such as the ITU-T G.hn standard) open the possibility of using home coaxial cable for high-speed home networking applications (Ethernet over coax).

In the 20th century they carried long distance telephone connections.

Patch cable

A patch cable is an electrical or optical cable used to connect one electronic or optical device to another for signal routing. Devices of different types (e.g. a switch connected to a computer, or a switch connected to a router) are connected with patch cords. It is a very fast connection speed. Patch cords are usually produced in many different colors so as to be easily distinguishable,^[2] and are relatively short, perhaps no longer than two meters.

Ethernet (crossover) cable

An Ethernet crossover cable is a type of Ethernet cable used to connect computing devices together directly where they would normally be connected via a network switch, hub orrouter, such as directly connecting two personal computers via their network adapters. Some newer Ethernet devices support the use of cross-over cables in the place of patch cables.

Power lines

Although power wires are not designed for networking applications, new technologies like Power line communication allows these wires to also be used to interconnect home computers, peripherals or other networked consumer products. On December 2008, the ITU-T adopted Recommendation G.hn/G.9960 as the first worldwide standard for high-speed powerline communications.^[3] G.hn also specifies communications over phonelines and coaxial cables.

for more information you can download this ppt on cabling.

network cabling PPT

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Bluetooth Technology explained

Bluetooth Technology explained

By Unknown   01:51   No comments:

Bluetooth wireless technology (IEEE 802.15.1) is a short-range communications technology originally intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are threefold: robustness, low power, and low cost. Bluetooth has been designed in a uniform way. This way it enables a wide range of devices to connect and communicate with each other by using the Bluetooth wireless communication protocol. The Bluetooth technology has achieved global acceptance in such a way that any Bluetooth-enabled electronic device, almost everywhere in the world, is able to connect to other Bluetooth-enabled devices in its proximity. Bluetooth-enabled electronic devices connect and communicate wirelessly through short-range, ad hoc networks known as piconets. Each device can simultaneously communicate with up to seven other devices within a single piconet. Each device can also belong to several piconets simultaneously. Piconets are established dynamically and automatically as Bluetooth-enabled devices enter and leave radio proximity. One of the main strengths of the Bluetooth wireless technology is the ability to handle data and voice transmissions simultaneously. This enables users to use a hands-free headset for voice calls, printing, fax capabilities, synchronizing PDA’s, laptops, and mobile phone applications to name a few.
An important aspect of this thesis is about the scalability of Bluetooth broadcasting. Since scalability can sometimes be a rather vague concept, we give a short explanation of the term. An important aspect of software products is how they are able to cope with growth. For example, how does the system handle an increase in users or data traffic? This property of a software system is usually referred to as scalability. A more detailed specification of the concept is given by André Bondi, who defines it as follows: ‘Scalability is a desirable attribute of a network, system, or process. The concept connotes the ability of a system to accommodate an increasing number of elements or objects, to process growing volumes of work gracefully, and/or to be susceptible to enlargement.’ Whenever a system meets these requirements we can say that thesystem scales. In this thesis scalability comes down to the question if the system is capable of dealing with large groups of users equipped with Bluetooth enabled devices capable of receiving simple text messages.

Passive Broadcasting

The first type of business deals with broadcasting from a central location, which we will call passive broadcasting. Most of these companies sell both the hardware and software to enable this. For example, BlueCasting by Filter WorldWide, one of the major players in the market which made the news in August 2005 when they distributed merchandise for the British pop band Coldplay, offers a product family divided into four types of systems. They offer solutions for small retail shops, one-off events such as music festivals, and even larger areas such as airports and train stations. The latest descendant in the family is a system that provides an interactive touchscreen allowing users to interact directly with the system. BlueCasting is an example of a product that comes with both hardware (one or more BlueCast Servers) and software (BlueCast Campaign Management System) which is used to provide remote setup, maintenance and reporting.
Besides this type of companies, i.e. the ones that are selling the total package, other companies have dedicated themselves to providing just the hardware. An example is BlueGiga. According to their website their BlueGiga Access Servers are used by more than 350 Bluetooth Marketing companies in more than 65 countries. They sell two lines of products: Bluetooth Modules and Bluetooth Access Servers. The modules are described as ‘completely integrated, certified, high-performance Radio Frequency products including all needed Bluetooth profiles’. Access Servers are sold in the form of Access Points (up to 7 connections) and Access Servers (up to 21 connections). Besides this they also sell the BlueGiga Solution Manager (BSM). This is a web-based remote management and monitoring platform for BlueGiga Access Servers that can be used to simultaneously upgrade, monitor and configure a large number of BlueGiga Access Servers, instead of configuring each device one-by-one.

Bluetooth Core System Architecture :

The transceiver operates in the globally unlicensed ISM band at 2.4 GHz. The bit rateis 1 Megabit per second and can be boosted to 2 or 3 Mb/s with Enhanced Data Rate[EDR]. The 79 channels in the band are ordered from channel number 0-78 and arespaced 1 MHz beginning at 2402 GHz. Bluetooth-enabled devices that arecommunicating share a radio channel and are synchronized to a common clock andfrequency hopping pattern. Frequency hopping is used to make the protocol morerobust to interference from other devices operating in the same band. The physicalchannel is sub-divided into time units known as slots. Data is transmitted betweenBluetooth-enabled devices in packets. These packets are situated in the slots. Packetscan fill one or more consecutive slots, allowing larger data chunks to be transmitted ifthe circumstances admit this. Bluetooth is primarily designed for low power consumption and affordability and hasa relatively short range (1, 10 or 100 meters). It makes use of low-cost transceivermicrochips that are embedded in each device.

The Bluetooth Baseband is the part of the Bluetooth system that specifies or implements the medium access and physical layer procedures between Bluetooth devices. Several devices can be joined together in what is called a piconet. One device owns the clock and the frequency hopping pattern and is called the master. Two or more piconets can be joined in what is called a scatternet. To form a scatternet, some units, called gateways, belong to different piconets. Such a unit can be a slave unit in more than one piconet but can act as a master in only one. Besides this, it can transmit and receive data in only one piconet at a time. To visualize this, imagine the following. You are on the phone with a friend, using your Bluetooth headset, while at the same time you are uploading pictures from your computer to your phone. Your phone now acts as a gateway, being the master in the piconet with your headset and slave in the one with your computer.

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Change your IP in just a Minute

Change your IP in just a Minute

By Unknown   08:39   No comments:

Hello everyone, today I am going to show you how to change your ip address in just few seconds to enhance your browsing of the internet.


1. Click on "Start" in the bottom left hand corner of screen
2. Click on "Run"
3. Type in "command" and hit ok

You should now be at an MSDOS prompt screen.

4. Type "ipconfig /release" just like that, and hit "enter"

5. Type "exit" and leave the prompt

6. Right-click on "Network Places" or "My Network Places" on your desktop.

7. Click on "properties"

You should now be on a screen with something titled "Local Area Connection", or something close to that, and, if you have a network hooked up, all of your other networks.

8. Right click on "Local Area Connection" and click "properties"

9. Double-click on the "Internet Protocol (TCP/IP)" from the list under the "General" tab

10. Click on "Use the following IP address" under the "General" tab

11. Create an IP address (It doesn't matter what it is. I just type 1 and 2 until i fill the area up).

12. Press "Tab" and it should automatically fill in the "Subnet Mask" section with default numbers.

13. Hit the "Ok" button here

14. Hit the "Ok" button again

You should now be back to the "Local Area Connection" screen.

15. Right-click back on "Local Area Connection" and go to properties again.

16. Go back to the "TCP/IP" settings

17. This time, select "Obtain an IP address automatically"

tongue.gif 18. Hit "Ok"

19. Hit "Ok" again

20. You now have a new IP address

With a little practice, you can easily get this process down to 15 seconds.

P.S:

This only changes your dynamic IP address, not your ISP/IP address. If you plan on hacking a website with this trick be extremely careful, because if they try a little, they can trace it back

This tutorial is only for education purpose. This information must be used carefully only on your own terms.!!

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INTERNET - The Largest Network of the World

INTERNET - The Largest Network of the World

By Unknown   01:58   No comments:

Good Afternoon Guyz.. Today I am sharing some information about INTERNET.

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to link several billion devices worldwide. It is an international network of networks that consists of millions of private, public, academic, business, and government packet switched networks, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), the infrastructure to support email, and peer-to-peer networks for file sharing and telephony.

The origins of the Internet date back to research commissioned by the United States government in the 1960s to build robust, fault-tolerant communication via computer networks.^[1] While this work, together with work in the United Kingdom and France, led to important precursor networks, they were not the Internet. There is no consensus on the exact date when the modern Internet came into being, but sometime in the early to mid-1980s is considered reasonable.^[2] From that point, the network experienced decades of sustained exponential growth as generations of institutional, personal, and mobile computers were connected to it.

The funding of a new U.S. backbone by the National Science Foundation in the 1980s, as well as private funding for other commercial backbones, led to worldwide participation in the development of new networking technologies, and the merger of many networks.^[3] Though the Internet has been widely used by academia since the 1980s, the commercialization of what was by the 1990s an international network resulted in its popularization and incorporation into virtually every aspect of modern human life. As of June 2012, more than 2.4 billion people—over a third of the world's human population—have used the services of the Internet; approximately 100 times more people than were using it in 1995.^[4][5] Internet use grew rapidly in the West from the mid-1990s to early 2000s and from the late 1990s to present in the developing world. In 1994 only 3% of American classrooms had access to the Internet while by 2002 92% did.^[6]

Most traditional communications media including telephone, music, film, and television are being reshaped or redefined by the Internet, giving birth to new services such as voice over Internet Protocol (VoIP) and Internet Protocol television (IPTV). Newspaper, book, and other print publishing are adapting towebsite technology, or are reshaped into blogging and web feeds. The Internet has enabled and accelerated new forms of human interactions through instant messaging, Internet forums, and social networking. Online shopping has boomed both for major retail outlets and small artisans and traders. Business-to-business and financial services on the Internet affect supply chains across entire industries.

For more details You can See the Full article here..::: INTERNET

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Components of a Computer Network

Components of a Computer Network

By Unknown   01:20   No comments:

Computer network components include the major parts that are needed to install a network both at the office and home level. Before delving into the installation process, you should be familiar with each part so that you could choose and buy the right component that fits with your network system.
Computer networks share common devices, functions, and features including servers, clients, transmission media, shared data, shared printers and other hardware and software resources, network interface card(NIC), local operating system(LOS), and the network operating system(NOS).

Servers - Servers are computers that hold shared files, programs, and the network operating system. Servers provide access to network resources to all the users of the network. There are many different kinds of servers, and one server can provide several functions. For example, there are file servers, print servers, mail servers, communication servers, database servers, print servers, fax servers and web servers, to name a few.

Clients - Clients are computers that access and use the network and shared network resources. Client computers are basically the customers(users) of the network, as they request and receive services from the servers.

Transmission Media - Transmission media are the facilities used to interconnect computers in a network, such as twisted-pair wire, coaxial cable, and optical fiber cable. Transmission media are sometimes called channels, links or lines.

Shared data - Shared data are data that file servers provide to clients such as data files, printer access programs and e-mail.

Shared printers and other peripherals - Shared printers and peripherals are hardware resources provided to the users of the network by servers. Resources provided include data files, printers, software, or any other items used by clients on the network.

Network Interface Card - Each computer in a network has a special expansion card called a network interface card(NIC). The NIC prepares(formats) and sends data, receives data, and controls data flow between the computer and the network. On the transmit side, the NIC passes frames of data on to the physical layer, which transmits the data to the physical link. On the receiver's side, the NIC processes bits received from the physical layer and processes the message based on its contents.

Local Operating System - A local operating system allows personal computers to access files, print to a local printer, and have and use one or more disk and CD drives that are located on the computer. Examples are MS-DOS, Unix, Linux, Windows 2000, Windows 98, Windows XP etc.

Network Operating System - The network operating system is a program that runs on computers and servers, and allows the computers to communicate over the network.

Hub - Hub is a device that splits a network connection into multiple computers. It is like a distribution center. When a computer request information from a network or a specific computer, it sends the request to the hub through a cable. The hub will receive the request and transmit it to the entire network. Each computer in the network should then figure out whether the broadcast data is for them or not.

Switch - Switch is a telecommunication device grouped as one of computer network components. Switch is like a Hub but built in with advanced features. It uses physical device addresses in each incoming messages so that it can deliver the message to the right destination or port.

Like Hub, switch don’t broadcast the received message to entire network, rather before sending it checks to which system or port should the message be sent. In other words switch connects the source and destination directly which increases the speed of the network. Both switch and hub have common features: Multiple RJ-45 ports, power supply and connection lights.

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