Thursday, October 13, 2005

Don't hang yourself with your network cable

We've been having a lot of fun on our campus this year!

Not really. Imagine a college campus where students, faculty, and administrative staff intermittently cannot access the network. They frequently cannot access their email, courses, notwork files, anything. Yes, this is the college that falsely celebrates being the first "wireless" campus in the state. What is really funny is that the college's advertising slogan is "get connected!"

Now imagine that failure is never complete. For instance, in a class of 40 students perhaps 15 can get on the network but you can't. Perhaps you try again later and you can login but only once or twice. Now imagine that your are paying $1,600+ per years for this privelege. Imagine you are now into the 7th week of suffering this problem. Would you be a little frustrated?

This really is the current situation on our campus.

What happened? Like so many other small liberal arts colleges our IT department is understaffed with "home-grown" personnel. They are overworked and under-informed. Over the summer two independent contractors were hired to lay network cable. However, at least one of the contractors laid the wrong cable. The problem is that there are two standards in making CAT-5 network cable. Without specifications a contractor may lay either T-568A or T-568B cable. Each works fine as long as the entire network is wired the same way. But you cannot mix the two!

CAT-5 network cable consists of 8 sets of twisted-pair copper wire. In general, the quality of the wire is greater as the number of twists increases. Each set is shielded and color-coded in pairs. The colors are green, yellow, blue, and brown. Each color has a solid and a striped set or wire. See Ethernet Cable: Color Coding Standards by clicking on hte title of this article.

Four to these wire sets aren't used by the network and four are. Two of the used set of used for sending data and the other two are used for receiving data. Each of these pairs has a wire that carries + and another that carries - signals. So you can see that if these wires aren't connected properly you could easily have data that ran into a dead-end.

When you attempt to connect to the network a series of signals must be successfully passed back and forth between your computer and the network server to complete the login process. This is also true any time your want to transmit or receive data. The specific path data takes from your computer to the server varies. If your data hits a dead-end the signal bounces around for quite awhile creating excessive network traffic. Your computer is impatient. It repeats the transmission making the matter worse. At some point the operating system will see that there's a lot of non-sense going on and will disable your network card. This can occur quickly when viewed in human time.

Of couse, most college students, faculty, administrators don't understand this. All they know is that their computer is broke. Unfortunately, there are too few campus IT directors and support personnel that know it too.

They 7th week of the semester is quickly coming to an end and the problem still persists. Classs attendance is dropping.
The campus computer committee has recognized the need to raise the priority of computing on campus and their powerless to affect positive change and Many students are talking about transferring to other schools. Who could blame them?

Meanwhile I'm thinking about how Nero fiddled while Rome burned.

Copyright 2005 by Mark Leon Winegar


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