In the previous example, Alice sends the message "secret" to Bob, but the network she uses for that is not made explicit.
We now introduce the network as a grey bar located to the right of the agents. Compared to the previous, we now have an extra step, which represents the message going through the network.
To visualise what is going in the network, we indicate on the message the expected sender and recipient. We also introduce an explicit Network Stack, which contains all the messages exchanged over the network. Each message in the stack is associated with a unique identifier, and a status, which starts with the "/" symbol. We consider two statuses at this stage:
We introduce the attacker in the next part.