Buying Knowledge

Buying Knowledge
By Rod Deluhery

A slight problem

The other day our dispatch center called our computer office, saying “the network is slow”. For a large city police dispatch center, this is not a good thing. It wasn’t a busy day, but the dispatch people where still a bit annoyed at the problem. Jim, the dispatch super gave me the weird look. “You know, this is the same thing that was happening last time, and it was the network. It wasn’t a CAD problem”, Jim said. “True, but I don’t see anything wrong. . .yet”. I said, a little worried but no panic yet. I continued to look at the problem, thinking it was probably the server or database. Finally I started doing some more network tests. “I think I found part of the problem. . .we are losing pings on the network. It’s network related, at least part of it, anyway.” I said. Suddenly the problem was mine and my blood pressure went up. I scrambled to find the problem. Using Ethereal, I captured some data on the CAD network vlan, nothing there. Then I captured data on the other ports of the switch. Whoa, massive amounts of data flooding the network. Aha, this must be what is slowing it down! But what was it, all this UDP traffic? Soon the deluge of data stopped, but dispatch was not quite satisfied. “What can we do to prevent this next time?” the dispatch operator asked me. “Well, we can discuss it, after I find out what it was. But there are some things we can do. One is to buy a dedicated network switch for CAD users, and separate the CAD network.“ “How can we better isolate the problem next time? Jim asks, trying to find a resolution. “Well, I can write up some things on how to better troubleshoot these issues. Well I suppose I could document some things to test next time you see this.” I say, feeling a little better that I actually know something about the problem now. What happened that made this incident different than any other computer problem? The issue was it brought a metropolitan 911 dispatch center to a point where they could almost not dispatch calls. A bad thing!