Fiddler 之弱网测试（2G,3G,4G）

1、模拟弱网环境

打开Fiddler，Rules->Performance->勾选 Simulate Modem Speeds，勾选之后访问网站会发现网络慢了很多

2、Fiddler弱网的原理

Rules—>Cutomize Rules打开CustomRules.js 文档

在文件中搜索关键字，m_SimulateModem

1.

   // Cause Fiddler to delay HTTP traffic to simulate typical 56k modem conditions
    public static RulesOption("Simulate &Modem Speeds", "Per&formance")
    var m_SimulateModem: boolean = false;

2.

if (m_SimulateModem) {
            // Delay sends by 300ms per KB uploaded.
            oSession["request-trickle-delay"] = "300";
            // Delay receives by 150ms per KB downloaded.
            oSession["response-trickle-delay"] = "150";
        }

让我们来分析一下这几行代码：

• 首先来判断m_SimulateModem是否为true，也就是是否设置了弱网模式。

• 如果为弱网模式。则分析代码

• oSession[“request-trickle-delay”] = “300”; 注释的也很明白，Delay sends by 300ms per KB uploaded.上传1KB需要300ms，

  转化一下上传速度：1Kb/0.3s = 10/3(KB/s)，也就是 3.33kb/s ，到达2G网络标准。

• 如果你想设置上传的速度为50KB/s，你则需要设置Delay 时间为 20ms

• 同样的方法，也可以限制上传的速度，调整oSession[“response-trickle-delay”]即可。

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网络	上行	下载
2G	2.7K	9.6K
3G	1.8M	7.2M
4G	50M	100M

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所以得出：2G网络配置

if (m_SimulateModem) {
            // Delay sends by 300ms per KB uploaded.
            oSession["request-trickle-delay"] = "300";
            // Delay receives by 150ms per KB downloaded.
            oSession["response-trickle-delay"] = "150";
        }

3G 网络配置,3G 应该是2G网络估值的1000倍速率，也就是上行和下载除去1000。

if (m_SimulateModem) {
            // Delay sends by 300ms per KB uploaded.
            oSession["request-trickle-delay"] = "0.3";
            // Delay receives by 150ms per KB downloaded.
            oSession["response-trickle-delay"] = "0.15";
        }

4G网络配置，上行为3G的25倍，下载为15倍，放开延迟即可。