Chapter 18: Network Performance Anxiety


The term network performance refers to how efficiently the network responds to users' needs. Obviously, any access to resources that involves the network is slower than similar access that doesn't involve the network. For example, opening a Word document that resides on a network file server takes longer than opening a similar document that resides on the user's local hard drive. However, it shouldn't take much longer. If it does, you have a network performance problem.

This chapter is a general introduction to the practice of tuning your network so that it performs as well as possible. Keep in mind that many specific bits of network tuning advice are scattered throughout this book. In this chapter, you can find some specific techniques for analyzing your network's performance, taking corrective action when a performance problem develops, and charting your progress.

Why Administrators Hate Performance Problems

Network performance problems are among the most difficult network problems to track down and solve. If a user simply can't access the network, it usually doesn't take long to figure out why: The cable is unplugged, a network card is malfunctioning, or the user doesn't have permission to access the resource, for example. After you do a little investigating, the problem usually reveals itself, and you fix it and move on to the next problem.

Unfortunately, performance problems are messier. Here are just a few reasons that network administrators hate performance problems:

  • Performance problems are difficult to quantify. Exactly how much slower is the network now than it was a week ago, a month ago, or even a year ago? Sometimes the network just feels slow, but you can't quite define exactly how slow it really is.

  • Performance problems usually develop gradually. Sometimes a network slows down suddenly and drastically. More often, though, the network gradually gets slower, a little bit at a time, until one day its users notice that the network is slow.

  • Performance problems often go unreported. Users gripe about the problem to each other around the water cooler, but they don't formally contact you to let you know that the network seems 10 percent slower than usual. As long as they can still access the network, they just assume that the problem is temporary or that they're imagining a problem.

  • Many performance problems are intermittent. Sometimes a user calls you and complains that a certain network operation has become slower than molasses, and by the time you get to that person's desk, the operation performs in a snap. Sometimes you can find a pattern to the intermittent behavior, such as it's slower in the morning than in the afternoon or it's slow only while backups are running or while the printer is working. At other times, you can't find a pattern: Sometimes the operation is slow, and sometimes it isn't.

  • Performance tuning isn't an exact science. Improving performance sometimes involves educated guesswork. Will upgrading all users from 100 Mbps to 1 Gbps improve performance? Probably. Will segmenting the network improve performance? Maybe. Will adding another 4GB of RAM to the server improve performance? Hopefully.

  • The solution to a performance problem is sometimes a hard sell. If a user can't access the network because of a malfunctioning component, the purchase of a replacement is usually undeniably justified. However, if the network is slow and you think that you can fix it by upgrading the entire network to gigabit Ethernet, you may have trouble selling management on the upgrade.




Networking For Dummies
Networking For Dummies
ISBN: 0470534052
EAN: 2147483647
Year: 2004
Pages: 254
Authors: Doug Lowe

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