[mKCP] 下载速度很快但YouTube很慢

[neteroster]

提交 Issue 之前请先阅读 Issue 指引，然后回答下面的问题，谢谢。
Please answer the following questions before submitting your issue. Thank you.

1. 你正在使用哪个版本的 V2Ray？（如果服务器和客户端使用了不同版本，请注明）
2. What version of V2Ray are you using?

V2.5.2 Both Server & Client

2. 你的使用场景是什么？比如使用 Chrome 通过 Socks/VMess 代理观看 YouTube 视频。
3. What your scenario of using V2Ray? E.g., Watching YouTube videos in Chrome via Socks/VMess proxy.

使用Chrome通过VMess协议和mKCP协议搭配代理观看YouTube视频

3. 你看到的不正常的现象是什么？
4. What did you see?

下载速度可以达到1.5M/s，fast.com测速13Mbps但YouTube速度仅500~2000Kbps
(ps: 使用kcptun无此现象，YouTube可达11000Kbps)

4. 你期待看到的正确表现是怎样的？
5. What do you expected to see instead?

YouTube速度应接近下载速度。

5. 请附上你的配置文件。
6. Please attach your configuration file.

SERVER:

{
  "log" : {
    "access": "/root/v2ray-access.log",
    "error": "/root/v2ray-error.log",
    "loglevel": "debug"
  },
  "inbound": {
    "port": 999,
    "protocol": "vmess",
    "settings": {
      "clients": [
        {
          "id": "xxx",
          "level": 1
        }
      ]
    },
    "streamSettings": {
      "network": "kcp"
    }
  },
  "outbound": {
    "protocol": "freedom",
    "settings": {}
  },
  "outboundDetour": [
    {
      "protocol": "blackhole",
      "settings": {},
      "tag": "blocked"
    }
  ],
  "routing": {
    "strategy": "rules",
    "settings": {
      "rules": [
        {
          "type": "field",
          "ip": [
            "0.0.0.0/8",
            "10.0.0.0/8",
            "100.64.0.0/10",
            "127.0.0.0/8",
            "169.254.0.0/16",
            "172.16.0.0/12",
            "192.0.0.0/24",
            "192.0.2.0/24",
            "192.168.0.0/16",
            "198.18.0.0/15",
            "198.51.100.0/24",
            "203.0.113.0/24",
            "::1/128",
            "fc00::/7",
            "fe80::/10"
          ],
          "outboundTag": "blocked"
        }
      ]
    }
  },
  "transport": {
    "kcpSettings": {
      "mtu": 1400,
      "tti": 30,
      "uplinkCapacity": 12,
      "downlinkCapacity": 100,
      "congestion": false,
      "readBufferSize": 1,
      "writeBufferSize": 1,
      "header": {
        "type": "srtp"
      }
    }
  }
}

CLIENT

{
  "inbound": {
    "port": 1086,
    "protocol": "socks",
    "settings": {
      "auth": "noauth",
      "udp": false
    }
  },
  "outbound": {
    "protocol": "vmess",
    "settings": {
      "vnext": [
        {
          "address": "xxx",
          "port": 999,
          "users": [
            {"id": "xxx"}
          ]
        }
      ]
    },
    "streamSettings": {
      "network": "kcp"
    }
  },
  "outboundDetour": [
    {
      "protocol": "freedom",
      "settings": {},
      "tag": "direct"
    }
  ],
  "routing": {
    "strategy": "rules",
    "settings": {
      "rules": [
        {
          "type": "field",
          "ip": [
            "0.0.0.0/8",
            "10.0.0.0/8",
            "100.64.0.0/10",
            "127.0.0.0/8",
            "169.254.0.0/16",
            "172.16.0.0/12",
            "192.0.0.0/24",
            "192.0.2.0/24",
            "192.168.0.0/16",
            "198.18.0.0/15",
            "198.51.100.0/24",
            "203.0.113.0/24",
            "::1/128",
            "fc00::/7",
            "fe80::/10"
          ],
          "outboundTag": "direct"
        }
      ]
    }
  },
  "transport": {
    "kcpSettings": {
	  "mtu": 1400,
	  "tti": 30,
	  "uplinkCapacity": 12,
	  "downlinkCapacity": 100,
	  "congestion": false,
	  "readBufferSize": 1,
	  "writeBufferSize": 1,
	  "header": {
	    "type": "srtp"
	  }
	}
  }
}

[ghost]

SERVER:

        "kcpSettings": {
            "mtu": 1350,
            "tti": 20,
            "uplinkCapacity": 5,
            "downlinkCapacity": 5,
            "congestion": false,
            "readBufferSize": 2,
            "writeBufferSize": 2,
            "header": {
                "type": "srtp"
            }
        },

CLIENT:

        "kcpSettings": {
            "mtu": 1350,
            "tti": 20,
            "uplinkCapacity": 5,
            "downlinkCapacity": 100,
            "congestion": false,
            "readBufferSize": 2,
            "writeBufferSize": 2,
            "header": {
                "type": "srtp"
            }
        },

另外，再开着拥塞控制：
SERVER:

        "kcpSettings": {
            "mtu": 1350,
            "tti": 20,
            "uplinkCapacity": 5,
            "downlinkCapacity": 5,
            "congestion": true,
            "readBufferSize": 2,
            "writeBufferSize": 2,
            "header": {
                "type": "srtp"
            }
        },

CLIENT:

        "kcpSettings": {
            "mtu": 1350,
            "tti": 20,
            "uplinkCapacity": 5,
            "downlinkCapacity": 100,
            "congestion": true,
            "readBufferSize": 2,
            "writeBufferSize": 2,
            "header": {
                "type": "srtp"
            }
        },

两种方法都试试。
另外建议把DNS功能开起来（毕竟Youtube是Google自家的业务）。

[v2ray]

@lizongzeshunshun 把服务器端的 uplinkCapacity 降到 3 以下。uplinkCapacity 的单位是 MB，根据你的实际速度，大约是 15 Mbps / 8 ~= 2 MBps