When a network performs poorly, its users often complain to the folks running it, demanding improvements. To improve the performance, the operators must first determine exactly what is going on. To find out what is really happening, the operators must make measurements. In this section we will look at network performance measurements. The discussion below is based on the work of Mogul (1993).
The basic loop used to improve network performance contains the following steps:
1. Measure the relevant network parameters and performance.
2. Try to understand what is going on.
當一個網(wǎng)絡的運行效果很差的時候，它的用戶通常會向網(wǎng)絡運行商抱怨并要求提高網(wǎng)絡的質(zhì)量。為了改善網(wǎng)絡的性能，網(wǎng)絡操作人員首先必須確定發(fā)生了什么問題。為了找出真正的問題所在，操作人員必須進行測量工作。在這一小節(jié)中，我們來看一看網(wǎng)絡性能的測量問題。下面的討論以Mogul(1993)的工作為基礎(chǔ)。
用來改善網(wǎng)絡性能的基本循環(huán)過程包括以下步驟：
（1） 測量有關(guān)的網(wǎng)絡參數(shù)和性能。
（2） 試圖理解當前的網(wǎng)絡狀況。
（3） 改變一個參數(shù)。
這些步驟不斷重復，直到網(wǎng)絡的性能已經(jīng)足夠好，或者改善性能的全部空間都已經(jīng)被發(fā)掘出來了。