Consistently inconsistent ping times

Internet access discussion, including Fusion, IP Broadband, and Gigabit Fiber!
8 posts Page 1 of 1
by aanon4 » Sun Jun 28, 2020 10:53 pm
So this is driving me bats. The ping time from my firewall to the downstream hop (Sonic fiber) is 1-2ms .. except every 2 seconds it consistently jumps 100-200ms for about 0.3 seconds, before returning to the more usual 1-2ms. I have no idea why. I've tried different firewall hardware (both pfSense mind you) but the problem persists. The internal network is fine (and this ping-ing is happening from the firewall anyway).

So, just me? The command i'm using to see this is 'ping -i 0.1 <downstream ip address>'.
by anthony.n » Mon Jun 29, 2020 11:29 am
Our nodes do not prioritize responding to pings so that may be what you are seeing. Are you having issues with responses/latency outside of our network? If ping time is consistently low to a destination beyond that hop then this would be expected behavior. Try running a traceroute to another destination to get a full picture.
by aanon4 » Mon Jun 29, 2020 12:01 pm
I see the same thing with 'ping -i 0.1'. It's the consistency of this problem I find so weird. If this was some traffic priority thing I'd expect it to vary in some way, but it doesn't.

The first line of traceroute (100ms delay, 20 queries) to looks like this:

Code: Select all

1 (  1.245 ms  1.656 ms  1.515 ms  1.469 ms  509.206 ms  82.820 ms  51.213 ms  1.465 ms  1.553 ms  1.529 ms  0.987 ms  2.083 ms  0.928 ms  1.568 ms  0.811 ms  1.368 ms  19.573 ms  559.281 ms  1.553 ms  16.688 ms

Again you see these moments where the time bumps up from the usual ~1ms to ~500ms and, again, it's the consistency of these bumps that's so odd to me.

I've not given up on it being some failing hardware on my end, so I'll replacing more tomorrow and see if it changes anything.
by anthony.n » Mon Jun 29, 2020 1:33 pm
Your traceroute results are exactly what we would expect. You would get similar results across most of our services using different devices. I don't believe swapping hardware would change much but you are welcome to try.
by aanon4 » Mon Jun 29, 2020 1:59 pm
Could you explain a little about why this behavior pattern is expected and so consistent?
by aanon4 » Mon Jun 29, 2020 10:41 pm
Well I'm going to have to open a ticket with Sonic. The problem persists and about once a day get's so bad that I get packet loss and the network goes down completely. In desperation I just plugged a laptop into the ONT but I still see the same issues (so I guess it's not my hardware at least). Tried new cables - still the same. My RTT on pings (as measure by pfSense - a rolling average) used to always be sub 5ms, but these days it's 120ms to 200ms.
by anthony.n » Tue Jun 30, 2020 10:22 am
If you are having issues when connected straight into the ONT, try power cycling the ONT and make sure the Ethernet cable is securely plugged in. If problems persist we may need to setup a dispatch.
by aanon4 » Tue Jun 30, 2020 11:25 am
So, after much messing and testing, I've concluded this problem is related to outgoing traffic - the more of it there is, and the more consistent it is, the more I see this problem. I'm not doing anything terribly exciting - incoming vpns for family and a minecraft server for the kids and their friends - but once I increase the load on those (consistently 20+ Mb/s outgoing say) the problems becomes really obvious. You can still see the issue at lower traffic levels too, but there the ping times are only going up to 10ms which is hardly problematic.

Now as far as I know Sonic doesn't pull any traffic shaping shenanigans, so I'm at a loss as to what's going on (and yes, power cycled the ONT, got a new ONT last week, new cables, different new cables .. still the same). I had another Sonic customer run this test for me (they have the same 2 down/1 up configuration) and they don't see this issue at all.
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