When is enough information enough.
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| Bus topology |
How do you know when you have enough information to make a decision? Can you ever have too much information? I am not sure if I have mentioned this before but I was a trainer in the IT industry for 20 years. I began with application classes such as word, excel, word perfect (anyone remember it) and many others. When an opportunity opened up in what we call technical training I jump at it. Now I was teaching Microsoft, Comp Tia and Cisco certification classes. I taught classes for a corporate training company as well as at the local community college. There are many interesting dimensions to teaching these technologies. I would like to highlight one of these.
I am going to start with a story from one of my classes. I was teaching a basic networking class. I am not sure what one since most of the basic classes are the same regardless of vender. At this time I had been teaching for about 5 years and had been quite successful. In all the basic classes you present the differences between broadcast and unicast messages. A broadcast message is sent from one computer on a network and is received by all other computers. All computers received the broadcast whether or not they needed it. A unicast was sent from one computer on a network and was only received by one other computer. Generally the receiving computer would be the only one that needed to receive the message. The lesson being that a unicast message was more efficient because only the 2 computers involved in the conversation receive or send the message. The remaining computers are not using resources to process the signals.
I was presenting this concept in class and had a diagram similar to the one at the top of this blog. In the middle of my presentation (probably for the 100th time), I had a massive brain stoppage. I am sure some of the clients saw my eyes spin rapidly and sensed my utter disbelief. I realized at that moment that what I was saying and what I had said 100 times before was blatantly incorrect. Referring to the diagram at the top. A message sent from computer 1 to computer 2 is simply an electrical signal. The electrical signal leaves computer 1 and travels down the wire to the main wire (called the bus). The signal then travels along the bus to the junction between the bus and the wire connecting computer x. this is were my brain went crazy. I realized that there is no way in the physical world that an electrical signal could be forced to bypass the computer x's wire and continue only on the bus. Likewise with all the other computers. I realized that a signal sent from any computer will physically travel to all other computers. I does not matter whether it is a broadcast or a unicast, an electrical signal will travel to all computers.
I was able to recover from this shocking discovery and continue with class. It took about a week and I was able to more fully understand this technology. I was now able to more concisely present the technology and what was happening to the signals as the traversed the entire network. I was able to then present the newer networking technologies and how they controlled the electrical signals and in the end why implementing them made networks more secure and efficient.
My main point here is why I was never called out for this obvious shortcoming in my presentation of the technology. I had many very intelligent clients prior to this and still this was never brought out. Of the hundreds of previous clients one of them must have understood this inaccuracy. Here are some thoughts on this:
1.) Relevancy: The bus topology was being phased out so this concept was more of a learning tool rather than a technology a client would implement.
2.) Results or conclusions: The way that this information was presented did lead to a correct result. A unicast is a more effective form of transmission. The reason for this efficiency is not in the way the signals travel within the network. This is a critical idea. It is possible to garner the correct conclusion even if we do not properly understand the facts. We can understand enough to properly conclude one aspect of the issue. The true effectiveness of a unicast is in how messages are addressed on a network and how computers process these addresses. In this case a further technology called network switching could only be properly implemented when one understands the way addresses are processed by computers. Just because we are correct doesn't mean we actually understand.
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