Sunday, May 15, 2011

Network and communication technologies

Network and communication technologies

As we all know, the first device for communication had been invented by Alexander Graham Bell in 1876. Starting from this, the scientist has struggled to improve the ability of communication for large-distance with the help of networking technology that appear in 1969. The development in network and communication technology is still undergoing a rapid development by the introduction to the “Mobile Computing” in the 1990s and new developments are continually expanding its role in modern communication.

Mobile Computing is defined as a generic term describing your ability to use technology 'untethered', that is not physically connected, or in remote or mobile (non static) environments. The term is evolved in modern usage such that it requires that the mobile computing activity be connected wirelessly to and through the internet or to and through a private network. This connection ties the mobile device to centrally located information and/or application software through the use of battery powered, portable, and wireless computing and communication devices. This includes devices like laptops with wireless LAN or wireless WAN technology, smart mobile phones, wearable computers and Personal Digital Assistants (PDAs) with Bluetooth or IRDA interfaces.

Nowadays, there are many type of internet technology that are offered to the users. One example of it is Voice over Internet Protocol (VoIP). The service of Voip is, voice information is converted into digital packets and sent over the Internet, and then converted back into analog signals before reaching the phone receiver at the other end. With hardware based VoIP phone services, your phone has been fitted with an adapter that connects to your high-speed Internet connection. When you make a call, it goes through your local telephone company to a VoIP provider, and then over the Internet to the called party's local telephone company. There are also software based VoIP phone services, where you use a microphone headset plugged into your computer and make calls, which are routed through your cable modem, by using the keyboard. VoIP can also be run over a private data network.

The big advantage of VoIP is that voice information sent over the Internet avoids using the fixed circuitry of traditional telephony networks – avoiding the tolls charged by traditional telephone service. This is why VoIP service providers can offer features such as free long-distance calls. The big disadvantage of VoIP is quality of service. While in theory because packets are sent over the best route at the time rather than through fixed routes, VoIP services would be reliable and consistent, in reality problems such as packet loss, bandwidth and plain old Internet outages make VoIP quality and reliability inconsistent. Broadband phones is one example of device that use VoIP to route calls through the Internet.

Another internet technology is blog, it is define as a frequent, chronological publication of personal thoughts and Web links. A blog is often a mixture of what is happening in a person's life and what is happening on the Web, a kind of hybrid diary/guide site, although there are as many unique types of blogs as there are people. People maintained blogs long before the term was coined, but the trend gained momentum with the introduction of automated published systems, most notably Blogger at blogger. com. Thousands of people use services such as Blogger to simplify and accelerate the publishing process. Blogs are alternatively called web logs or weblogs. However, "blog" seems less likely to cause confusion, as "web log" can also mean a server's log files.

Nowadays, there are many type of network can be used by users. The first example is the virtual private network (VPN). A VPN utilizes public telecommunications networks to conduct private data communications. Most VPN implementations use the Internet as the public infrastructure and a variety of specialized protocols to support private communications through the Internet. VPN follows a client and server approach. VPN clients authenticate users, encrypt data, and otherwise manage sessions with VPN servers utilizing a technique called tunneling. VPN clients and VPN servers are typically used in these three scenariosto support remote access to an intranet, to support connections between multiple intranets within the same organization, and to join networks between two organizations, forming an extranet.

The main benefit of a VPN is the lower cost needed to support this technology compared to alternatives like traditional leased lines or remote access servers. VPN users typically interact with simple graphical client programsThese applications support creating tunnels, setting configuration parameters, and connecting to and disconnecting from the VPN server. VPN solutions utilize several different network protocols including PPTP, L2TP, IPsec, and SOCKS.

VPN servers can also connect directly to other VPN servers. A VPN server-to-server connection extends the intranet or extranet to span multiple networks. Many vendors have developed VPN hardware and software products. Some of these do not interoperate due to the immaturity of some VPN standards.

The second example is the Worldwide Interoperability for Microwave Access is defined as (WiMAX) by the WiMAX Forum, formed in June 2001 to promote conformance and interoperability of the IEEE 802. 16 standard, officially known as Wireless MAN. WiMAX aims to provide wireless data over long distances, in a variety of different ways, from point to point links to full mobile cellular type access. In practical terms this enables a user, for example, to browse the Internet on a laptop computer without physically connecting the laptop to a wall jack. The Forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL. "

The third example is the Bluetooth. This wireless technology enables communication between Bluetooth-compatible devices. It is used for short-range connections between desktop and laptop computers, PDAs (like the Palm Pilot or Handspring Visor), digital cameras, scanners, cellular phones, and printers. Infrared once served the same purpose as Bluetooth, but it had a number of drawbacks. For example, if there was an object placed between the two communicating devices, the transmission would be interrupted. (You may have noticed this limitation when using a television remote control). Also, the Infrared-based communication was slow and devices were often incompatible with each other.

Bluetooth takes care of all these limitations. Because the technology is based on radio waves, there can be objects or even walls placed between the communicating devices and the connection won't be disrupted. Also, Bluetooth uses a standard 2. 4 GHz frequency so that all Bluetooth-enabled devices will be compatible with each other. The only drawback of Bluetooth is that, because of its high frequency, its range is limited to 30 feet. While this is easily enough for transferring data within the same room, if you are walking in your back yard and want to transfer the address book from your cell phone to your computer in your basement, you might be out of luck. However, the short range can be seen as a positive aspect as well, since it adds to the security of Bluetooth communication.

The fourth network that will be discuss is Wireless Fidelity (WiFi); the popular term for 802. 11b wireless networks which include both a WiFi "hot spot" to broadcast data as well as a WiFi-enabled device to receive the data; commonly used to access the Web by some handheld devices with built-in WiFi capabilities or expansion slots with WiFi cards; WiFi essentially replaces the need for Ethernet cables on some devices; WiFi local area networks use high frequency radio signals which can be received within a relatively short range of a few hundred feet.

In conclusion the development in network and communication technology has a big potential in the future due to the new developments which are continually expanding its role in modern communication. It is obvious because the requirement for this technology is increasing day by day.