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.
 
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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.
 
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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.
 
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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?
 
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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.

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?
 
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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.
 
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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.
 
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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.
 
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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.
 
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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.
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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Worked fine with the Merlin FW and Asus RT-n66u for me - just set upload QoS so no one application can use more than 90% of your max upstream (better if the modem does it).

Typical Asus rubbish though - needed 3rd party firmware to sort most of the things Asus should have got right out the box and several mechanical parts like switches are the cheapest possible despite supposedly being a premium router... and won't last forever...

EDIT: Could only ever get decent WiFi on the n66u with the Merlin FW - official or other branches would always result in either poor signal or after a couple of days increasingly things just never getting a connection over the WiFi until the router was rebooted. Ended up ditching it.
 
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What router and firmware are you using?

RT-AC87U and I'm on the last available one 384.13_10. Been meaning to replace it with a Netgear R7000 I got from here and FreshTomato firmware.

One thing to take note is, if you turn on QoS, the CTF (Cut Through Forwarding) is disabled which is essentially hardware acceleration. It basically means the packets no longer bypass the CPU so you QoS.
This limits your download speed through the WAN port to around 280 Mb/s I believe. Not a huge problem for most people but I learnt this lesson when I was trying to find out why my VM 350 connection was slower than what I used to get.

I've found the download speed limiting doesn't have as much of an effect on the bloat compared to the upload, so I usually set the download to like 95%

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.

I would have suggest to set up a TBB graph, that would indicate if it is your line itself rather than the upload choking it.
Although reading through it seems the RT-N66U with the shibby firmware works fine ruling your line being the problem, it just needs the QoS setup properly on the ASUS.

It could just require a factory reset and a flash of the latest merlin firmware on the ASUS router that might fix things. It could be a problem with that specific router so might be worth a search about it.

Another thing to try is to install amtm using Entware, and then installing FlexQoS or CakeQoS. That stuff requires you plug in a flash drive to the router for storage space and is more advanced stuff though, but great if you want customisation.
 
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j9CCXAe

aY5xYIg
 
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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
 
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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.
 
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If you don't mind can you tell me how did you setup that and what do I need to buy.

Sure, I got a Google WiFi kit with 2 wifi pods and I have the main pod connected to the router by ethernet cable which provides the WiFi downstairs and I have the second pod placed on the 1st floor to link up with the first pod wirelessly, and that supplies WiFi to the rest of the house including in the loft.

On my phone getting around 133/66 speeds with that which is fine. I think I need a 3rd pod for better signal distribution but it allows me to not rely on the router WiFi (which is disabled and turned off).

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?
 
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I am getting packet loss on 3rd hop which suggest problem some where with my ISP?
https://imgur.com/j9CCXAe
https://imgur.com/aY5xYIg

Looks like it from that data, but if it is caused there which router you use shouldn't make much difference. I don't have any experience with fibre/vdsl etc only ever used cable. Have been very lucky in that respect that we've never really been in a congested area, only for a few months years ago and some during lockdown.

I guess the ping problem will only show up when you're routed through that network.

using both routers is pretty simple -
1. setup the rt-n66u in router mode as usual
2. connnect a lan port from the rt-n66u to the wan port on the ac88u.
3.Setup the ac88u as you normally would (it'll work breifly in double nat). go to, Administration -> Operation mode and choose Access Point (AP) Mode / AI Mesh Router in AP Mode (which is the second one down on my ax88u).

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.
 
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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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