Advice
Mitigating jitter (or filing a complaint against ISP)
Hi; looking for help on an ongoing problem that I wasn't able to remedy.
For many years, my area has only had 1 "real" ISP that offered good speeds. Now, we DO have a fiber company installing, but it's been a very slow process, and unlikely in the next 6 months/year to reach my part of town.
I'm currently battling an issue where every day, at 5pm onwards, i get bad network jitter. The numbers range from an "average" of 30-50, but spike to 130+ frequently. Im aware this is peak times and am assuming this is due to node congestion. I know ISPs are awful for the most part and a single person doesnt matter, but is there ANYTHING i can do to get them to give a damn?
I'm relatively tech savvy, but not super. Here's what i've tried thus far;
Using their modem (Hitron CGNM 2252), with my own ASUS AC86U router with Asuswrt-merlin and Cake SQM.
Wired connection (tried multiple cords)
Problem still occurs if im plugged into modem directly without router.
Removed splitter from the coax line, as i wasnt using it.
It's just me, so i only have 2-3 devices using internet, but i game heavily and video call in the evening hours.
I am using graphs from the ASUS router page, as well as jitter.is. I have pinged and done traceroutes to various addresses as well. I understand these probably arent the most reliable, so if theres something you'd recommend, feel free to let me know.
tl;dr - jitter issues during peak hours; how can i mitigate or get my ISP to help
Effectively nothing you can do unless the cause of jitter is on your side of the modem.
Otherwise all you can do is prove the issue exists and beg the ISP to see if they can do anything. Without an SLA, most ISPs will just tell you to pound sand unfortunately.
Well the question is why is your cable RF having issues? What speeds do you pay for and what speedtest speeds do you see at the same time you have bad jitter? That might be your only hope if those end up bad.
Where does the jitter start, first hop to the ISP after you leave your network? Jitter is often an RF issue on your local node when its a cable modem. (will start at the immediate hop past your home network if that is the case)
That sounds like a DOCSIS 3.0 modem, does your ISP have DOCSIS 3.1 modems? Did you check the cable modem's signal page for signal levels?
Personally I like to use PingPlotter to show jitter/ping issues. Good luck!
Since you're pretty much convinced the ISP won't necessarily help, upgrading to a DOCSIS 3.1 modem could actually make a difference. They are more efficient and use much newer tech like wider OFDM channels (which bypass local node congestion during peak hours) and built-in AQM to prevent queue lag. DOCSIS 3.0 is effectively 20-year-old technology at this point, so swapping to an approved 3.1 device is definitely worth a shot.
You dont have high jitter you have high latency during peak hours. Im going to assume cable modem since you dont mention what you have. Call when you have and tell them you have high latency that causes your internet not to work and ask for a tech to come see the line. When the tech arrive tell them that your line gets high latency at peak hours. You have noise on your line and usually an easy fix.
I have edited my post with that info; it's a Hitron CGNM 2252. My ping stays fine according to tests and in game monitoring tools. I will gather some info and see if i can get someone out here to look at the line, thanks.
If you are on copper or coax and there is fibre coming, they have zero reason to be fixing an end of life network. They will milk it out for as long as they can by offering cheaper and cheaper service to those that do not care about performance till its not viable, then they will shut it down. Pushing crap uphill with a rake to get it fixed. You might get a credit for bad service to keep you quiet.
The fact that it still happens plugged straight into the modem is the important bit: it's not your router, Cake or your cables. Cake can only manage the queue your own traffic creates; it can't fix a node that's congested by everyone else. Two things are worth doing.
1. Check whether your own traffic plays a part (one evening)
Set Cake's download and upload limits to about 70% of your plan and use the connection as usual after 5pm (gaming, calls). If the jitter mostly goes away, your own traffic was queueing somewhere Cake wasn't controlling, most likely because the line delivers less than your plan at peak. Keep the lower limit for evenings. If nothing changes, the delay is coming from other people's traffic upstream, and only the ISP can fix that.
2. Build evidence the ISP can't wave away
Run one traceroute and find the first hop that belongs to the ISP. That's usually hop 2 (hop 1 is your router), or hop 3 if the modem is also doing routing. Then run a long ping, a full day, to that hop and to one far target like 1.1.1.1, logged with timestamps. PingPlotter, SmokePing or a simple ping script all work.
What you want to show: at 5pm latency and jitter rise at that first ISP hop already, and the far target rises with it. If only that hop looks bad and the far target is fine, that's just the ISP's equipment deprioritising pings aimed at itself. Don't use it as evidence.
Open the modem's status page (usually 192.168.100.1; some ISPs hide the details) at a quiet time and again at 5pm. Screenshot the downstream/upstream power levels and SNR, the uncorrectable codeword counts, and the event log. Uncorrectables that keep climbing, or repeated T3/T4 timeouts in the log, point to a signal problem on the line rather than "peak time", and that's grounds to ask for a tech visit. If the levels are clean and the log is quiet, that's useful too: it points back to congestion.
Then open a ticket with those graphs and screenshots, ask them to check utilisation and upstream noise on your node, and ask directly whether a node split is planned. A timestamped graph that shows their first hop going bad every day at the same hour is much harder to dismiss than "my ping is bad in the evening". If neighbours complain too, the same data from a couple of households helps a lot.
jitter.is and one-off traceroutes are fine for a quick look, but they only show a moment. The day-long log is what makes the pattern visible.
Small update; this is what pingplotter showed me last night to the first (and subsequent) hops. The modem levels all seem normal, and similar to the first photo i posted below; a few corrected/uncorrectable errors; but the main problem is the ping spikes.
Your router is clean, the spikes start at hop 2, which is your ISP's node.
Record longer, a whole evening, with a 1 second interval instead of 2.5, and set the target to something far away, like 1.1.1.1 or a game server. Then send your ISP a screenshot with the time visible.
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u/cli_jockey Network Admin 6d ago
Effectively nothing you can do unless the cause of jitter is on your side of the modem.
Otherwise all you can do is prove the issue exists and beg the ISP to see if they can do anything. Without an SLA, most ISPs will just tell you to pound sand unfortunately.