And here is what it looks like from my MacBook
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Agreed. The ping RTTs are way higher than I am used to seeing. And there’s too much variability.
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I'd not seen the jitter before, but it definitely looked suspect. I realized that I had plugged the hub (while troubleshooting) into a downstream device, /not/ the switch I mentioned before. I moved it back to the primary switch and so far no packets lost in 24h, so that's a win! I can troubleshoot the other device separately.
I'm going to also set up smokeping or equivalent (probably Prometheus plus an ICMP exporter) and keep a closer eye on it. If high loss or jitter recurs, I'll see if I can correlate it with on-device conditions rather than network conditions.
This was a good clue — it wasn't where I remembered attached to the network. On the same switch:
32572 packets transmitted, 32572 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.464/2.355/16.897/1.797 ms
So I think the original problem was the jumbo frames issue, and the secondary behavior (intermittent loss but not locking up) was an actual network problem on a different switch. The secondary behavior didn't appear until I began troubleshooting.
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I've marked this as the solution — eliminating other network issues, disabling jumbo frames has kept things stable.
I'd love to see this fixed at the base level, still, as I dislike network equipment crashing due to received packets. That's an unpleasant vulnerability.
Thanks to all!
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FYI, this is fixed in the C-8 Pro. Because this requires a change to the underlying Linux OS, and not just the hub JVM platform, I do not envision this being fixed via a platform update. And an OS update is more difficult and runs the risk of bricking the device.
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Hadn’t heard about that. Happen to have a link to any recent threads?
Not off hand, but perhaps @gopher.ny can comment.
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@jhaustin , can you PM me the hub id? I'll check it out.
Right, we have not heard of any C8 pros freezing outright because of jumbo frames.
Risk of bricking the device is the biggie here. The (very limited) OS on the hub has no in-place upgrade or recovery abilities.
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This is good to know, because I do have use for jumbo frames elsewhere on my network (currently the segment Hubitat is on has them disabled). Not all switches support per-VLAN MTU settings.
