Group05_Illuminati:How Internet Works?

Internet is a global network of computers. Every computer that is connected to the Internet is part of a network. For example, a modem can be used to dial a local number to connect to an Internet Service Provider (ISP). At work, a local area network might be used but still connection to the Internet is made using an ISP that the company has contracted with. When a connection to an ISP is made, we become part of their network. The ISP may then connect to a larger network and become part of their network. The Internet is simply a network of networks.
Each computer connected to the Internet must have a unique address. This address is known as an IP (Internet Protocol) address. Every computer needs one to communicate on the Internet and it is usually built into the computer's operating system. The Internet uses a protocol stack referred to as the TCP/IP protocol stack because of the two major communication protocols used.The Internet backbone is made up of many large networks which interconnect with each other. These large networks are known as Network Service Providers or NSPs.These networks peer with each other to exchange packet traffic. Each NSP is required to connect to three Network Access Points or NAPs. At the NAPs, packet traffic may jump from one NSP's backbone to another NSP's backbone. NSPs also interconnect at Metropolitian Area Networks or MAEs. MAEs serve the same purpose as the NAPs but are privately owned. NAPs were the original Internet interconnect points. Both NAPs and MAEs are referred to as Internet Exchange Points or IXs. NSPs also sell bandwidth to smaller networks, such as ISPs and smaller bandwidth providers.The ISP maintains a pool of modems for their dial-in customers. This is managed by some form of computer (usually a dedicated one) which controls data flow from the modem pool to a backbone or dedicated line router. This setup may be referred to as a port server, as it 'serves' access to the network. Billing and usage information is usually collected here as well. No computer knows where any of the other computers are, and packets do not get sent to every computer. The information used to get packets to their destinations are contained in routing tables kept by each router connected to the Internet.. A router is usually connected between networks to route packets between them. Each router knows about it's sub-networks and which IP addresses they use. When a packet arrives at a router, the router examines the IP address put there by the IP protocol layer on the originating computer. The router checks it's routing table. If the network containing the IP address is found, the packet is sent to that network.After your packets traverse the phone network and your ISP's local equipment, they are routed onto the ISP's backbone or a backbone the ISP buys bandwidth from. From here the packets will usually journey through several routers and over several backbones, dedicated lines, and other networks until they find their destination,