I've come here to ask this, after a fairly lengthy exchange with technical support.
A small part of my life, is playing the occasional game of CS:GO. Recently, I started to see loss appear in game (on network stats) and it was causing artifacts in game (delay before kill confirmation, juddering movement, this kind of thing).
The loss was really variable. Mostly 0-5%, but jumping as high as 30% at times. So, as a bit of a technical person I thought I would investigate. Enabling packet logging in game allowed me to see, actually there was 0% loss. Not a single packet was actually lost (good news, I would say). But, this percentage I saw were arriving out of order, and the game client had no way to make use of these out of date packets. So, they were as good as lost.
OK. So, still a problem for gaming I guess.
So I performed some tests with iperf, and found a few interesting things.
1: With small packets, (200 payload) out of order packets could be as high as 25%
2: Larger packets (1420 bytes) has less problems generally 3-5%
3: Very predictably packets that were forced to be fragmented had MUCH less out of order issues (consider how that works to understand why)
4: There were zero packets out of order over IPv6 (less load, different routing?)
5: Tests performed over 4g and wifi (vs fully wired VDSL 80/20 connection) had only the occasional bout of OOO packets, and these were clumped together (almost certainly caused by error detection/correction on either of the two unreliable transport mechanisms).
Zen support say, this is essentially tough luck and I must live with this. But, my question is. When other ISPs don't have the problem. When their own IPv6 network doesn't have the problem, and I have less of a problem on a cellular network over wifi... At what point is the problem too big?
So I'm making it an open question. Because, I don't really know if I'm making a mountain out of a molehill here.
I wonder if any other Zen users here are CS:GO players (or other UDP based online games) and are seeing issues. I suppose extremely low latency VoIP could throw up some issues too.