In the first introductory article, we saw that an intranet is a private network built using the Internet's technology and communication protocols. What makes all intranet communications possible are two protocols for exchanging information: The Transmission Control Protocol (TCP) and the Internet Protocol (IP). Together, these protocols are known as TCP/IP. They are separate protocols, not a single one, although they are tightly woven together to allow for the most efficient communications.
These two protocols perform their magic by doing something that seems deceptively simple. They break data into sections called packets, deliver those packets to the proper destinations on an intranet (or onto the Internet), and after they've been delivered, they reassemble the packets into their original form so that they can be viewed and used by the recipient. TCP performs the work of separating the data into packets and reassembling it, while IP is responsible for making sure that the packets are sent to the right destination. Reminds me of something learnt in school physics. Plank's Quantum Theory. Supposedly, this was the original idea behind the conceivement of the TCP/IP.
TCP/IP is used because intranets (and the Internet) are what is known as packet-switched networks. In a packet-switched network, information is sent in many small packets over many different routes at the same time and reassembled at the receiving end. Because packet-switched networks can always use the most efficient means of delivery by tapping into unused network resources, they make the best use of the network's resources. Though it is the most commonly used protocol, TCP/IP is the not the only network protocol. But I am going to limit my range to TCP/IP only since this is the most widely accepted and implemented protocol.
An intranet may not be the only network used within a corporation. An intranet may be connected to other corporate networks, in particular to NetWare-based networks. When this happens, the intranet can be used as a way to route data between the NetWare networks. To do this a NetWare network sends packets of data, and essentially disguises its own network protocols inside IP packets, and then uses IP protocols to send the data from one network to another. When an intranet is used like this, it is referred to as IP tunneling.
What distinguishes an Intranet from other PC networks is the fact that it uses the Internet protocol (TCP/IP) as its basic mode of data transfer. When you send information across an intranet, the data is broken into small packets. The packets are sent independently through a series of switches called routers. Once all the packets arrive at their destination, they are recombined into their original form. As mentioned above, the Transmission Control Protocol breaks the data into packets and recombines them on the receiving end. The Internet Protocol handles the routing of the data and makes sure it gets sent to the proper destination.
Next time, we shall see the actual way the data is interpreted via the segmented mode of transfer.
