[masraum]

Originally Posted by beepbeep

What people often miss is that it is not just speed that is important (as long as it is "good enough" and you do not download/upload huge amounts of data), but latency too.

I measured my "loaded" latency by pegging my Gbit line and ping latency went from 10ms to "all over the place". When I fitted proper router with SQM shaper I could have almost constant latency no matter how hard I loaded the line. I figured I could live happily with 100Mbit (Netflix, Zoom, Teams, Youtube included) as long as i had proper QoS shaper.

But of course, ISP will gladly sell you faster/more expensive subscription than equip you with gateway powerful enough to enforce queueing.

Yes and no. It's less about latency and more about jitter (variability of latency). I used to work for a company that provided voice and data for (primarily) oil companies and the military over satellite. You can upload/download things and carry on a conversation on the phone (albeit with a bit of delay, but voice quality is fine) with adequate bandwidth and a round trip latency in the 500-800ms range.

That said, lower latency is better. I'm usually pretty happy with latency in the 30-60ms range. But the latency is heavily dependent upon geographic location (ie, the distance between you and the item that you're testing latency to).

What really sucks is when latency jumps around (like you saw). Now, that again may not be a big deal on a loaded link because latency checks (usually ping or traceroute) are going to be impacted before most other traffic. So if you're using 99% of your bandwidth for some download or streaming or something, your latency is likely to jump around because the other traffic is not.

QoS is actually going to slow things down, because there are 2 options when doing QoS, 1 drop traffic that exceeds a limit. So you get to a certain limit and then anything over the limit gets dropped and your session/application (TCP has to replace the dropped data). The second option is to form a queue with the traffic, often kind of like creating a merge lane for 8 lanes to merge down to 1 or 2 lanes. What that means is that traffic backs up, and if it backs up too much then you drop traffic, and that's bad too. If you have enough buffers so you don't drop traffic, then you only slow things down.