In the same way as in the network shown in Figure 8, this network conveys the data to the receiver, selecting the most appropriate route for it to travel. In order to do this, the network may need to manipulate and store or retrieve data.
Your computer sends the FirstClass message into the internet, via your ISP connection, and the internet conveys the message to its destination, which is a computer at The Open University. The devices which make up the internet work together to select the most appropriate route for conveying the message. The internet is very complex so this will involve manipulating, retrieving and possibly storing data on the way.