Whenever I download big file (eg. games), my other devices get offline immediately

[Chaiyoabc]

as the topic says, I have experienced this every time I download something in any device in home network, internet won't work in other device(both Lan and Cable) I'm sure it's something to do with Netduma because normal router wouldn't have this problem. 

[Chaiyoabc]

no feedback? would you like a video? 

[Netduma Fraser]

This sounds like you're not using QoS/Anti-Bufferbloat and so the download is swallowing the entirety of your bandwidth. What are your QoS settings?

[Chaiyoabc]

21 hours ago, Netduma Fraser said:

This sounds like you're not using QoS/Anti-Bufferbloat and so the download is swallowing the entirety of your bandwidth. What are your QoS settings?

my qos setting is on default

 

[Netduma Fraser]

What do you mean by default? What it is after a factory reset? If so that's not enabled. Recommend starting with 'Always' and 70% for both download/upload and then following this guide so you can fine tune it to what works best when your connection is saturated: http://support.netduma.com/support/solutions/articles/16000074717-test-your-connection