July 25, 2005, 8:20 PM — You know, we (and especially I) throw the term performance around a lot. In networking, mentioning performance almost always implies throughput, and these two terms are frequently used interchangeably. Performance thus means how fast a given connection is in terms of bits per second.
Unfortunately, that definition is much too limited when we talk about wireless. As regular readers of this column know, the variable nature of the radio channel, and the consequential statistical behavior of wireless links, results in highly-variable throughput, which can range from just fine to nonexistent, and which, of course, can change on a moment-by-moment basis. This is perhaps the greatest frustration of any wireless user - after all, wired performance is highly predictable, especially when wired networks are carefully planned and overprovisioned, as is quite often the case today.
But the wireless environment is a lot tougher, so you never really know what you're going to get until you get it. The good news is that improvements in radio technology continue at what seems to be an accelerating pace, and lower costs allow us to overprovision in a manner analogous to that on wire (see my earlier article and whitepaper on dense deployments for more information). So wireless throughput continues to improve, but variability will almost always be with us as a fact of life.
But there's more to wireless performance than throughput alone. Let's consider some of the other dimensions of wireless performance, all of which influence throughput as well: