Yes, if you use FLEXQOS and set there IP range to a low priority then they will only show down when it's necessary for other higher priority classes to function. Make shore to adjust the bandwidht for each class to achieve what you want.
Morris
Well yes, but that will throw them under a bus. Lets say a mis-categorised Steam download starts or a 4K YouTube video starts buffering - on that connection speed it's going to take a few seconds, during which their reduced priority craters all of their connections. Zoom, Skype, VOIP phone, email, websites? You're on hold for 5 or 10 seconds, maybe longer if retransmits are required. This could be frustrating for his family if they constantly have 30 second delays, or video chats simply don't work due to dropped packets. This is why Tomato's 10 buckets were great. I only ever needed 7-8 of them. You could throw extra ones near the top, but limit the bandwidth. So they can have a very high priority.... 10-15mbit. That way their stuff works well, but they are very effectively throttled. Even if you have a giant steam download or some torrents going, consuming most of your bandwidth, they still get speedy prompt packet delivery - with the tradeoff being they can only access a small fraction of your full speed. I feel that's a very fair way to implement it.
@ragerys You could try something like this:
You can see that I have VOIP and Gaming right at the top - stuff that is mission critical, but under minimal use. Right below that categories/buckets start to consume a lot more bandwidth. If you put your family member down below (near the bottom), and they are doing VOIP or Zoom or whatever, their packets can be dropped or buffered if your connection is fully loaded. They might have ping spikes up to several seconds if your connection is
very heavily loaded. My lowest category often has 700ms ping spikes while the top ones typically only spike 20-30ms. This doesn't matter because of the traffic within the category, but I feel if you classify your family member down there, you're intentionally punishing them. Their internet will suck once your connection is full.
A quick concept: If two packets arrive at the same time, the higher priority one will go first - but in the case of bulk downloads (Torrents, Steam game downloads, etc.), a lot of the time you hit edge cases where packets arrive just *before* a VOIP or Gaming one. In that case, the low priority ones go out just before the higher priority ones arrive, and they end up waiting briefly. This manifests as higher but stable latency under heavy load. That can be really important for certain things - VOIP calls, gaming (if you hate rubber-banding / snapping backwards), Zoom/Skype, etc.
Do not classify all of your family member's traffic into one of the lowest categories unless you dislike them. You also can't let them strangle your most important stuff, though. Since you (apparently) can't use the Bandwidth Monitor device priority levels simultaneously with FlexQOS, I think the two possible places for their traffic (if laid out like mine) would be Web Surfing or Gaming, but with a lower (~50% or so) max speed limit. Since they are not prioritised lower than the super heavy use categories, their packets will take priority - up until their limit, after which all of your own rules and categories will take precedence for the remaining 50% bandwidth. You have access to 100% when they are not using any, but they are capped to 50% with slightly higher priority. Your connection will perform fine even if they are using theirs heavily, with it splitting roughly down the middle. Both of you get the benefit of QOS traffic shaping, but your whole connection somewhat fairly split, allocating around 50% each way under heavy load. (Tweak/adjust as necessary.) It is enforced by the higher priority level with a much lower speed cap. Putting him in Web Surfing though could have unintended side effects if you drop it to 50%, as some of your own usage shows up in there. A lot of web downloads show up under Other instead, but that doesn't matter - if you both are trying to do a "Web Surfing" thing, you will be robbing from him. It's easy to rob 50% accidentally, and then he only has 7.5mbit instead - but since it's split by the connection (
not by the IP), if you just happen to send through more connections of that type, you could sometimes take even more of his bandwidth and choke him out. It is not too likely since he has more connections classified into there, but it
could happen.
Putting him in Gaming solves that - unless of course you actually game. As then your gaming traffic is competing with all of his traffic, and you've limited the max bandwidth that the Gaming bucket can attain. That's a problem. While most games won't even use 5mbit let alone 15, there's tons of other things that he could do that will exceed that. If you happen to play games while he's doing something like Netflix/YouTube, and he is classified as Gaming, your gaming will suffer because of the 50% limit. Both of you will have dropped packets, but your actual gaming suffers from retransmits and rubber banding, while many other internet tasks simply won't notice.
So as you can see, there's no perfect solution here. The real solution is another empty unused bucket, sitting above Web Surfing and below Gaming. If it never gets classified into by AdaptiveQOS (just by your rule targeting his IPs), but you can order it and cap its speed, you can isolate his traffic and amount of bandwidth and keep it very fair. That's why Tomato's 10 were great. Empty categories are an asset - not a liability - for certain QOS / traffic shaping requirements. VOIP and Gaming would never approach 15mbit, so he'd always have his 40-50% allocation, and you'd always have your 50-100%.
Hope that helps in some way.