Technically, the Internet is those networks covered by tcp/ip protocols. These include those for the secure supply chain and dealing systems of the US aerospace and financial services industries. In practice, however, what most consumers, academics and small firms have access to is only any-to-any packet switching. This works as follows:

-All types of information - whether a text, a conversation, or a photograph - are transmitted in the form of bits (1s and 0s of computer code).

-As data enters the network, the stream of bits representing a message is divided into a series of short sections or "packets".

-A "label" is attached to each packet indicating its final destination, and its place in the message as a whole.

-As it travels through the network, each packet passes through a series of specialised computers known as "routers". Each router decides which is the most efficient path for the packet to take on the next stage of its journey. This decision is taken on the basis of the router's understanding of network connections and loading patterns at the moment of the packet's arrival at the router. The process is then repeated at each router the packet passes through.

-This decision that the router takes will change over time as the router's knowledge changes. As a result, the thousands of packets which comprise a particular message may each take different paths through the network. They are only re-assembled in the proper order at their final destination.

-The destination will acknowledge the receipt of each packet to the sending system. The sending system will resend any lost information.

-Packets are also acknowledged across the communications paths that link the routers.
The key point is that routers must make a copy of each packet in order to read and direct it. The life-span of these copies is limited to a fraction of a second. The routers also copy each packet as they send it on, so that the packet can be retransmitted if it is lost. This copy is retained until the packet's receipt is acknowledged, which could be up to a few seconds. These copies represent only an unintelligible fragment of a whole message. They are nevertheless essential for the functioning of the Internet.