I was cruising the Cisco Learning Network this morning when I came across a blog post entitled “Ever heard of Layer 8?” there. As a guy who’s been writing about and teaching this model since 1988, my immediate response was “Of course I’ve heard of Layer 8: it’s all about politics and religion, and other subjects on which there are lots of opinions and attitudes and precious little agreement.”
Here’s how poster Jared (an anonymous Cisco Designated VIP) describes Layer 8 in this post (n the context of the Cisco Certified Design Associate, or CCDA credential):
… to make a good design you need to know what the business and technological requirements are and you have to live within the business and technological constraints. Think about that for a minute. You have to design a network to deliver who knows what and you have to do it with certain constraints, usually a limited time line or budget. Have you ever found yourself in a meeting where a customer wants what is technologically impossible, against their company policy or so expens[iv]e that not even all the money in the world could afford what they want? I have… often. To make matters worse the customer may have multiple people present the business and technological constraints and goals and they may conflict with another person’s goals and constraints within the same organization. Then comes the process of debating, negotiating, hashing out the details to find some kind of compromise and to find a solution that will meet all of the goals and be achievable within the constraints that exist. It is this process that I refer to as the Layer 8.
There are some who argue, in fact, that Layer 8 is the most important of all the layers not only because of the reasons that Jared so convincingly lays out in the preceding discussion, but also because it’s where all the real work happens and energy gets expended. In fact, Jared goes on to describe this as a “political process” — entirely in keeping with the way I learned about it for the first time myself, circa 1987, as the level of the protocol stack where local influences come heavily into play: needs, wants, wishes, dislikes, biases, misconceptions, misperceptions, and so forth.
But there’s another way to think about that puts things into a more reasonable perspective: Layers 1 through 7 are out of the end user’s control, with the exception of minor configuration tweaks and communications options. The vast bulk of the architecture, the protocols, and the communications are set by design to make information exchange achievable. It’s only when you start getting into how networking will be used, what tasks and services it must support, and how it enables workers to work, business to be conducted, and other useful stuff to occur that things start get really interesting.
Though Layer 8 may be outside the scope of the OSI network reference model, it should never be far from the minds of IT professionals. This is where they earn their keep, and harness tools and technology in the interests of productivity and perhaps even profit. Layer 8 is indeed a province of opinion, emotion, and less precise understandings and statements of business goals and objectives. But it’s also where the rubber meets the road, and where IT must demonstrate a return on investment. Forget, ignore, or wish away this fundamental principle at your peril!