How to resolve the Wi-Fi frequently disconnected on OSX 解決 OSX 上 Wi-Fi 頻繁斷線的問題

If you found that Wi-Fi frequently disconnected or Wi-Fi spent 30-40 seconds returning to the normal from sleep mode on OSX, I suggest that you could change the maximum transmission unit (MTU) as a troubleshooting step.

如果你發現 OSX Wi-Fi 頻繁斷線、或 Wi-Fi 需要花30-40秒才能從休眠模式回覆正常連線，那我會建議你修改 MTU 的設定以解決這個問題。

Based on my testing 根據我的測試

I had tested several MTU values, but I found if I set MTU value to 1453, Wi-Fi connection almost could return to the normal from sleep mode in 10 seconds.

我測試過數個 MTU 值，但我發現只有設定成1453，Wi-Fi 幾乎能在10秒內從休眠模式恢復正常連線。

How to set MTU in OSX 如何在OSX內設定MTU

1. From the Apple menu, choose System Preferences. Click Network.
   請選擇“蘋果”選單 〉“系統偏好設定”，然後點選“網路”。
   
2. If you see a lock icon in the bottom left corner, click the lock icon and enter your administrator password.
   如果你看到左下角有一個鎖的圖案，點選這個鎖並輸入Admin的密碼就可解鎖。
   
3. In the left sidebar, select "Wi-Fi".
   從網路連線服務列表中選擇“Wi-Fi”。
   
4. Click the "Advanced..." button. And click the Hardware tab.
   點選“進階”，再點選“硬體”。
   
5. From the Configure: pop-up menu, choose "Manually".
   從“設定”彈出式選單中選擇“手動”。
   
6. From the MTU pop-up menu, choose "Custom".
   在"MTU"選單選擇"自定"
   
7. Enter your desired setting (1453).
   輸入1453。
   
8. Click OK, then click Apply to save your changes.
   點選右下角的"好"後，再選"套用"就可以儲存你的變更。