Data network protocols and data structures
A data network's purpose is to forward packets of information from end to end, as fast as possible. Several communication architectures emerged in the 1970s that described the requirements for a communications network. Among them were the OSI-RM from the International Standards Organization (ISO) and TCP/IP from the USA Department of Defense (DoD). While the first one – the OSI-RM – became a theoretical architecture used mostly for training purposes, in the last 25 years or so, the TCP/IP model became the sole architecture used for data networks.
Take a look at these two architectures in the following diagram. Note that, practically, they are relatively similar. While the OSI-RM describes the requirements for a data network in seven layers, the TCP/IP architecture describes it in four. However, the requirements are the same. Let's take a closer look:
Figure 2.1 – The OSI-RM and the TCP...
