From the Vault: 7 easies as far as the eye can see

A time when you could read data as it came across the wire

It has been one the great joys and pleasures of my life to have worked in Networking for essentially my entire adult life. For anyone keeping score, that’s a really long time. My first job in networking was managing async, bisync and SDLC-based networks. If you know what those protocols are, you know exactly the environment I am referring to.

We are talking about a time when link speeds were less than 300 bits per second to as much as 2400 or 9600 bits per second; a time when link speeds were soooooo slow, you could literally read the data, as it was coming across the wire; a time when analog modems would often lose their s^&t and the timing would go wrong, leading to nothing but garbage coming across the wire.

As I reflect, it is interesting to ponder how the human brain does pattern and signature recognition. When the analog modems would get out of (timing) sync with each other, then the garbage that resulted could not be interpreted in any meaningful way, the resulting “hex” codes were not intelligible; did not follow any patterns I was used to seeing. Which of course is exactly how I knew something was wrong, I did not understand what I was seeing / I had never seen it before.

When SDLC came along, the wire was filled with (hex) 0x7E, commonly referred to as 7 easies. This was a flag that was constantly put on the wire when a data frame was not being sent, in theory keeping certain circuitry awake, alert, and in sync. When data frames were being sent, the flags delimited where the data frame began and end, with the data frame protocol preventing a 0x7E from occurring within the data frame. For a NOC tech back then, 7 easies as far as the eye could see was not such a bad thing.

During this period, some time last century, Enterprise networks had much simpler routing, and many fewer nodes capable of routing. We had jobs simply because links were unreliable, and that is what we literally had to watch to keep services up. What is important to watch today has changed, as too has the nature of a NOC job.

Techies are problem solvers. There is a problem, the problem is addressed, new problems arise, and the cycle begins again. As a result, the nature of both problems and work is forever changing, even if we may still use some of the same human intuitions and heuristics over and over again. For example, I have never seen this before, I wonder if there is something wrong, hmmm? 🤔