Hands-On Network Programming with C# and .NET Core

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The origins of the OSI

The need for a standardized model for network implementations became apparent almost as soon as networking became possible. To that end, back in the late 1970s, two different organizations for governing standardization in computing set out to define such a model. The first of these organizations was the International Organization for Standardization (ISO). The other organization that set out to solve the same problem, at roughly the same time, was the International Telegraph and Telephone Consultative Committee (CCITT, initialized from the French translation of the name).

Interestingly, the shortened name for the International Organization for Standardization, ISO, is not an initialism of the name of the organization. Instead, since the name of the organization would be initialized differently in each language that it is recognized, the members chose to shorten the name to ISO. This is in reference of the Greek isos, which means equal, and speaks to the goal of the organization to bring about equal understanding.

The fact that two organizations sought to define their own model at roughly the same time as one another isn't entirely surprising. The problem was faced by engineers across a wide array of disciplines, and the lack of standardization was quickly becoming a bottleneck to progress in those disciplines. What is surprising, however, is how similar the solutions were to one another. Like Leibniz and Newton independently inventing calculus, these organizations incidentally arrived at a common solution to their common problem. However, this happy coincidence helped to expedite the standardization process, since the similarity of their solutions served to validate both models as being highly likely to be correct.

Given the success of both organization's efforts, it took only a handful of years before both models were merged into a single standard. Thus, in 1983, the Basic Reference Model for OSI was born. Over time, the name has, of course, been shortened to the OSI model. By 1984, each organization had published this new shared model under their own official reference documents, canonizing the model, and its specific protocols, within the international community. So, let's take a look at what that model entails.