Fromthesun: Internet Technologies

Network Architecture:

A lot of companies usually build interconnected network of computers, which may not extend the boundaries of their organizations, and this network is called as intranet. These low cost Internet compatible intranets are used for transmission of data like files, documents, and images for sharing among the company people.

The extranet is basically an intranet, which extends specifically beyond the boundaries of the organizations in order to communicate with entities like databases, authorized users, business partners, customers or suppliers.

The Internet is an example of a public network. The companies usually never use public network as their own extranet owing to the high security risk involved in the communication process.
A private network is a fully owned private leased-line or permanent telephone connection between at least two companies by connecting their intranets/extranets with each other. Here, the cost of the leased telephone line is costly and hence, if the number of companies increases in the available system, then the cost shoots up.

If an extranet that uses public networks such as Internet to send company sensitive data to partners, customers, suppliers or employees through a system known as IP tunneling, then it is called as a Virtual Private Network (Virtual means the network connection though seems to be permanent, is actually temporary). A secured virtual route through the Internet is created by IP tunneling for data transmission from one computer to another. This virtual route is created by VPN software, which encrypts the data in packet form, and again these encrypted packets are put inside another outer packet, where, this outer packet is called as IP wrapper, and this process is known as encapsulation. The web server sends the encapsulated packets to their destinations over the Internet, and the computer that receives the packet unwraps, and decrypts it using the same or compatible VPN software used in the server end in real time, and finally the data transaction is terminated.

Accessibility:

Internet Service Providers have various options for the individuals or groups or companies for accessing the Internet, and these options do always base on the bandwidth: this is the quantum of data that can travel through a communication line per unit of time. Upload or upstream bandwidth is measured by the quantum of data/information that can travel from the user computer to the Internet or web server during a specific period of time. Download or downstream bandwidth is measured by the rate of data/information that can travel from the web server to the user during a particular time period.

Internet Service Provider connects the user commonly through a local telephone service provider using a modem, but in order to get a better service or bandwidth, the modem is replaced by a Digital Subscriber Line switch, and this networking equipment is used via a technology called as Integrated Services Digital Network.

Big companies having huge Internet traffic connect to the Internet Service Provider using higher bandwidth leased line connection. The technology of the leased line connection varies depending mainly on the type of the cable. Example: A telephone line designed to carry 1 digital signal is called DS0 (Digital Signal Zero), & has a bandwidth of 56.00 Kbps, and a T1 or DS1 line carries 24 DS0 lines having a bandwidth of 1.544 Kbps, whereas, a T3 or DS3 line carries 760 DS0 lines or 30 DS1 lines having a bandwidth of 44.736 Mbps. Network Access Providers as good as Internet Backbone Routers use frame relay connection technology and optical fiber cable connection, where bandwidth is find out by the cable characteristics. Example: OC3 (Optical carrier 3) connection provides 156Mbps, OC12 – 622Mbps, OC48 – 2.5Gbps, and OC192 – 10Gbps of bandwidth.

Personal Area Networks are created by using a low bandwidth wireless connection through a technology called as Bluetooth, which works reliably over shorter distances, and consumes very less power. Wi-Fi or Wireless Ethernet having potential bandwidth is a wireless connection technology use in LANs, whose network specification number is 802.11n (upgrades from time to time). Within the range of a LAN, computers equipped with Wi-Fi network cards communicate via wireless access point (device which transmits network packets). Though cell phones were originally designed to handle voice communications, technology up gradation put them in wireless data communication.