Bufferbloat issue with Asus Routers

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I am having issues with bufferbloat which ends up in huge lag spikes during games. I have tried Asus RT-n66u and RT-ac88u both with original firmware and with merlin firmware without any luck. I have tried QOS as well.

I have managed to install Tomato (shibby) firmware on the RT-n66u which resolved the bufferbloat issues but wifi singal is really weak for some reason on this firmware.

Atleast 1 thing is clear so far that this is not hardware issue and and its not related to my ISP as well as tomato firmware is running for 3 days without any lag spikes.

I have got plusnet fibre, router is connected via BT modem. My download speed is around 75mb and upload speed is around 19mb.

Any help would be much appreciated in advance.
 
Did you set the Merlin firmware QOS on and limit the upload speed in the settings to like 80-90% of your max? Also what bufferbloat test site are you using? I've been using the QoS feature and it works well on Merlin giving me an A rating on thinkbroadband's speedtest site.
I limited my download to 65mb and upload to 10mb. I have used dslreports and fast.com.
 
Did you set the Merlin firmware QOS on and limit the upload speed in the settings to like 80-90% of your max? Also what bufferbloat test site are you using? I've been using the QoS feature and it works well on Merlin giving me an A rating on thinkbroadband's speedtest site.
What router and firmware are you using?
 
I know the RT-N66U is no longer supported by Merlin, have you tried the LTS fork ? This may have better wifi drivers for you. Have you tried a wired connection to the router?
I haven’t tried LTS fork but I have tried latest merlin firmware on rt-ac88u with no luck. Ideally I would like to use ac88u as wireless range is really good.
 
You might need to limit it to less than 65mb, and remember the cpu of the rt-n66u limits the qos to a max of around 60 mb on the rt-n66u in my experience. Also, with the later asus units hardware acceleration only works with adaptive qos. the other modes disable hardware acceleration, although that shouldn't be an issue with the ac88u. I've used both the ac68u and ax88u with adaptive qos and aslong as you are conservative with the speeds you enter they do work well. Note, this is on a virgin media 200mb connection (actual 220 down and 22 up) I use limits set to 200 down and 18 up (I've always found VM has more bufferbloat on download, so limiting the download so it drops packets before reaching that definitely helps - although some argue this doesn't work), also make sure this is done using a wired connection as wifi adds its own problems.

I forgot also, but sometimes the qos didn't work properly until the router was restarted. Hope this helps

Edit: forgot to mention ,,firmware used with the rt-n66u was both shibby and Toastman and rt-ac68u and ax88u is merlin.
I am using wired connection. I have also tried to limit the download speed to 60mb as well without any success.

Note: rt-N66u have been working fine in the past with the original firmware and whenever I used to get lag spike all I had to do is restart the router and that use the fix the issue but that was like once in 3/4 weeks.
 
Not sure I can offer much more help then, as i've found with even heavy use pings stay under pretty low, no lag spikes. When getting lag spikes in games how heavily is the connection being used and how high do the pings go? Might be worth leaving pingplotter running to get more info of exactly where the bufferbloat is comming from. I'd give merlin firmware another go, with adaptive qos and if problems still persist give cake a try (I think it's supported on the ac88u). If not, i'd use the rt-n66u as the router and ac88u as access point.
Could be just watching youtube or stream so not really under heavy load. Pings jumps from 11ms-18ms range to 800ms-900ms range for few seconds before returning back to normal. Will try again to install old merlin firmware on RT-ac88u and see how it goes.
 
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Not sure I can offer much more help then, as i've found with even heavy use pings stay under pretty low, no lag spikes. When getting lag spikes in games how heavily is the connection being used and how high do the pings go? Might be worth leaving pingplotter running to get more info of exactly where the bufferbloat is comming from. I'd give merlin firmware another go, with adaptive qos and if problems still persist give cake a try (I think it's supported on the ac88u). If not, i'd use the rt-n66u as the router and ac88u as access point.
I am getting packet loss on 3rd hop which suggest problem some where with my ISP?
https://imgur.com/j9CCXAe
https://imgur.com/aY5xYIg
 
I've set up a separate WiFi mesh for the WiFi part instead of relying on just the router. If you consider that, you might be able to switch to your other router which controls the QoS fine without big spikes, and have decent WiFi.
If you don't mind can you tell me how did you setup that and what do I need to buy.
 
Ideally you shouldn't need that as you've got a different problem. Did you try the factory reset and reflash on your ASUS router?
Thanks, I will probably wait for black Friday deals to pick up Google wifi kit but mean while I will disable wifi on my N66u and connect AC88u in access mode to handle my wifi. For whatever reason it seems Tomato firmware on N66u handling packet loss much better compare to N66u and ac88u on original and merlin firmwares. Really appreciate all the help and suggestions regarding this issue.
 
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Then all you need to do is setup the wifi, and your done, you don't need to move the cable on the ac88u from the wan to lan port as in access point mode the wan port is bridged to the lan connections. I wouldn't be surprised though based on your results that the lag spikes will keep happening.
I think I will struggle to make my ISP to look into the issue. Could be congestion issue at the local BT fibre broadband cabinet. As I said earlier tomato firmware on n66u seems lot more stable and handling packet loss much better and if I setup ac88u in access mode and let it handle my wifi hopefully that will resolve my wifi issues as well for now. Really appreciate all the help and suggestions regarding this issue.
 
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