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The TCP/IP Guide  9  Networking Fundamentals       9  Network Performance Issues and Concepts

Network Performance Issues and Concepts 1 Balancing Network Performance with Key Non-Performance Characteristics

Performance is probably the “mother of all buzzwords” in the computer industry. There are many people who consider it the ultimate goal of any computer or computer system, and by extension, any network. A lot of people spend many dollars and hours of time trying to maximize it. There's good reason for this: performance is very important. A network that does not offer adequate performance simply will not get the job done for those that rely on it. However, it is very important to keep performance in perspective. Successfully maximizing performance requires that you first take a step back and look at the issue in a big picture way.

The first question you must ask yourself is also the most essential one: how important is performance to you? Before you answer this question, recall the old auto racing adage: “speed costs money—how fast do you want to go?” While there are some situations where you can get much better performance in a network by spending just a little more money, in general, you don't get more performance without paying for it in some way. That may mean more dollar cost for the network, or it may mean a trade-off of some non-performance characteristic.

If you are designing or specifying a network, it's very important to keep in mind that your goal is to come up with a system that will meet the needs that were determined for it during requirements analysis. This means coming up with a network that has a level of performance that matches the requirements, and of course leaves some room for expansion. Unless you have an unlimited budget—and who does?—your objective is not “performance at any cost”. It is to create a network that meets all of your users' needs, including balancing performance and non-performance characteristics.

A primary reason why I make a point of trying to keep performance in perspective is that so many others do not—especially those who are trying to sell you things. Companies are constantly coming out with the “latest and greatest” high-performance networking technologies. The usual way that they try to sell them is by attempting to convince everyone that they just cannot live without this latest advance; that they “need” to upgrade—immediately, if not sooner! Well, it's simply not the case. As just one example, even though Ethernet hardware now exists that runs with a theoretical throughput of 10,000 megabits per second, there are many older networks that continue to work just fine at a hundredth that speed—or even a thousandth!

Finally, remember that designing a network is usually not an “irreversible”, permanent decision. Networks can be upgraded and expanded. While it is prudent to build some “slack” into any network to allow for growth, it is not wise to spend too much on planning for the future when changes can be made later. This is especially true given that network hardware prices drop over time. Again here, this is a matter of drawing an appropriate balance between future performance planning and budget.

Network Performance Issues and Concepts 1 Balancing Network Performance with Key Non-Performance Characteristics