SQM Struggle Continues

SQM struggle continues, been struggling to get it working as it supposed to or designed to work, SQM promise to solve any buffer bloating issue and improve ping especially for the gamers. If you look at my previous posts, you will find that I continue to have the issues despite trying all the suggestions, methods, you name it. either there Is something wrong with the SQM or am the only one who is having a bad luck. I have gone through few high end routers as well to rule out other possibilities, so far no luck, am not sure if it has anything to do with Xfinity cable internet or something else. I have played around with the standard OpenWRT Firmware as well as snapshots, Dave’s etc. and problem still exist, I use WRT3200 router and I have 100 Down and 5 Upload speed, it doesn’t matter if I put 10 Down and 1 Upload in the SQM, the same problem exists. Sometime when I refresh/restart the SQM things will improve immediately for few minutes before going downhill again, repeating the same helps but then I will have to constantly refresh/restart the SQM every few minutes to make it work as it should. Best way to describe the issue is take water hose as an example, you turn the water on and water runs through the pipe until you step on the hose, it’s like stepping and removing the foot on and off the hose, it feels like my SQM acts this way or in general even without SQM, the connection act the same way, again restarting the internet helps again for few minutes before doing the same.

If anyone have any idea on what’s happening, please advise

Sounds like an issue with your ISP modem or something else. Especially since you have tested it with different hardware and firmware versions all with the same result. Bring your router to someone not in your neighborhood and a different ISP and test it there. If it works fine there, you know the problem has to be with your ISP or the modem.

i have my own CM1000 modem, i have tested the same hardware and firmware at my parents and results are always the same, but they also have Xfinity, am quite sure if its related to ISP, then many people who have Xfinity should see the same problem.

Did you use that exact same modem and router at your parents' house?

i used the same modem and router, i switched mine with their and their with mine to see if anything changes, same issues and same pattern occurs.

Ahhhh, yeah, then it is weird. I am using SQM on David's build with a WRT32X and it works flawlessly with A+ results while I have a Puma chipset modem. I think it might be Xfinity in your neighborhood, town, city or area having issues. No clue where your parents live relative to you, but you get my point I hope :wink:

Try it at a friend that doesn't have Xfinity and see what happens. One thing though, are you sure you are bridged with the modems? Not double NATed?

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not sure about the Bridged or NAT, will have to look later on today and report back, on top of my head if i could remember i believe its in DHCP or Gateway or something like that

This leads me to believe you are not running SQM exclusively! I think that is your issue, you are either double NATing or just using the internal DHCP of the modem. This will defeat the SQM functionality!

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very well could be, no one ever pointed this out if this turns out to be true in my case, that would suck if its true because i spend so much time and resources into this lol

Agreed, though you do learn a lot from these very time consuming issues. I have been there more than once myself, it really matures you in networking :wink:


From SQM's perspective it does not really matter whether the modem is bridged or whether you use double NAT, as long as no device in your network bypasses your sqm-openwrt router by directly connecting to the docsis modem-router (be it via wifi or via wired ethernet). SQM needs to be in control of data on the true bottleneck and that requires that it knows about each and every packet sent (or at the very least almost all of the packets, a few additional ARP packets from your modem should not really matter too much, but a another computer say watching netflix connected directly to the modem-router will be an insurmountable challenge for sqm).


well now i need help setting this up, looks like its setup like this as of now:

config interface 'loopback'
	option ifname 'lo'
	option proto 'static'
	option ipaddr ''
	option netmask ''

config globals 'globals'
	option ula_prefix 'fdab:bbcc:401e::/48'

config interface 'lan'
	option type 'bridge'
	option ifname 'eth0.1'
	option proto 'static'
	option ipaddr ''
	option netmask ''
	option ip6assign '60'

config interface 'wan'
	option ifname 'eth1.2'
	option proto 'dhcp'

config interface 'wan6'
	option ifname 'eth1.2'
	option proto 'dhcpv6'

config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '1'

config switch_vlan
	option device 'switch0'
	option vlan '1'
	option ports '0 1 2 3 5t'

config switch_vlan
	option device 'switch0'
	option vlan '2'
	option ports '4 6t'

But the preferable option would be a modem in full bridge mode behind the router which is running SQM for the wan interface right? I was always told to avoid double NAT at any time...

Oh, I agree double NAT is a pain in the a**. But from SQM's perspective it does not matter. Sometimes double NAT is impossible to avoid.


Yeah, didn't explain it well enough, double NAT does influence some speed tests, so that might give you results that are not to your liking. But if you have put the router (not sure if you did or not) in the switch port and not the internet port, you are basically going around the SQM script altogether. Since we don't know those kind of details, I always assume the worst to eliminate those things as issues.

@Happi do you have problems when the only traffic to/from the Internet is your gaming traffic (e.g. all other devices are disconnected, and on your gaming device no programs apart from your game are running in foreground or background that could be accessing the Internet)?

If you have problems even when all the bandwidth is dedicated to your game, SQM wouldn't help, maybe your ISP network is congested which would be outside of your control, but you could try switching to a different ISP.

If the problems go away in that set up, you should be able to shape the traffic to fix the problems, so that it'd work as if your game had the whole bandwidth to itself. You could mark your gaming traffic with DSCP on your gaming device and apply strict prioritization on the router, so that other traffic would be prevented from competing with your gaming traffic (other traffic would only use the bandwidth not needed by your game), if you do it properly, you'd be able to play games with minimum latency while uploading/downloading heavily (e.g. running p2p file sharing programs like bittorrent). More information can be found in the post below

SQM with DSCP tagging for gaming is a great idea but with a default config of SQM + Layer_cake and most Network setups (e.g. OpenWrt Router with Wifi AP) this will only work for egress afaik, unless you work with veth, nftables or a script for ingress DSCP, which isn't always so easy to implement for many people (myself included).

@Happi mentioned that the connection was 100 down / 5 up, I'd hazard a guess that it's the egress traffic that's suffering from congestion.

Assuming the speed is in Mbps, 5Mbps upload isn't much nowadays, so cake with DSCP may not be sufficient as cake is designed to achieve fairness, it doesn't use strict prioritization, it prevents low priority traffic from being starved, so if the game requires higher percentage of bandwidth than what cake deems fair, the gaming traffic would be throttled and the latency would go up. prio qdisc on the other hand uses strict prioritization, so it would never throttle high priority traffic to benefit the low priority traffic.

While the fairness offered by cake is very useful when the broadband is shared by people who don't know each other well. I think it isn't always useful in a home network because it's unlikely that a family member would complain about p2p download not getting its fair share due to other family members using too much bandwidth for gaming etc, it's far more likely that the p2p downloading family member would throttle the speed willingly to reduce the impact on others. prio simply automates this dynamically in real-time while keeping network utilization maximized.

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i have tried everything, so far nothing has helped, including disabling all other devices or WIFI etc. i could definitely try another approach the one you just linked but i have no idea where to start, unless i could follow the tutorial or something. i have already tried hisham2630 approach and it didn't help me much, you can see my posts on those threads as well. it would be nice if you could share a full tutorial or something that goes step by step and i could give it a try. thanks

First we need to establish whether the problem could be solved by traffic shaping. Could you answer the question quoted below?

As a new user, I can't post more than 3 replies in a thread, so I'll keep updating this post until I'm allowed to post more replies

Update 1

Well, a traffic shaping script may work really well in one network and fail miserably in another. What's important is does the script address the problem you have , or even can the problem be fixed by traffic shaping? We don't want to start fixing a problem that's not fully understood as we could end up trying to fix the unfixable (e.g. game server is located on Mars resulting in high latency :slight_smile: ) . To get started, we first need to know what/where the problem is. Please do what I mentioned in my previous post again. If you can plug your gaming device directly to the modem, that would be better, otherwise please disable all SQM and traffic shaping on the router, I would recommend you factory reset OpenWrt and only configure the WAN (if it needs configuring) and keep all other devices disconnected (WiFi should be disabled by default after factory reset, so you'd just need to unplug Ethernet cables from the router), close/kill all foreground and background processes on your gaming device that could access the Internet.

After the test, ideally we should have a simple answer like

  • yes the problem happens even when the whole bandwidth is dedicated to the game, with no SQM or traffic shaping being applied


  • no the problem doesn't happen when the game is the only thing that's using the Internet, with no SQM or traffic shaping being applied

Update 2

That sounds like traffic shaping would help. If you plug your gaming device to the modem, does it go downhill over time too? When you get a chance, please do carry out the test suggested earlier.

Update 3

If you have this problem with all games, it would suggest that either there's something wrong with the ISP network (e.g. network is congested), or there's an issue with the signal to the modem (e.g. bad singal power level).
As you're getting problems even when XBOX One is the only device plugged to the modem, it's not something that SQM can fix.
As @Sparks suggested, it's best to log a fault with your ISP. If it's a signal problem, it's relatively easy to fix, in the UK, the ISP would arrange an engineer visit to adjust the power level etc at the customer's address, if it's network congestion, it could take time to expand the capacity.
You may want to check the bandwidth usage when the problem occurs to see if your game requires more than 5Mbps of upload bandwidth (which is unlikely). Factory reset OpenWrt and open http://openwrt.lan/cgi-bin/luci/admin/status/realtime/bandwidth , click on the tab that corresponds to your WAN and keep it open, take screenshots of the graph when the problem happens. I would keep SQM disabled until the problem is fixed otherwise it might interfere with diagnosis.

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