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Fulted
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Can you fix bufferbloat on VM?

350mb wired (cat7) results on dslreports test give a B for bufferbloat. I read that VM isn't the best for bufferbloat etc.. and I tried switching the router (superhub 3) into modem mode and retesting which lead to the same result. Does anyone know if buying a new router with SQM/QoS would help improve bufferbloat latency at all?

A friend of mine is on 500mb (SH3 also) using powerline adapters with more devices connected in his household and gets an A result. From what I read, speed doesn't play a huge part so upgrading would be pointless? 

 

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Sofia_B
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Re: Can you fix bufferbloat on VM?

Hi @Fulted

 

Welcome to the community and thanks for your post, we're happy to have you with us 🙂 

 

I'm sorry to hear you're having some bufferbloat issues, I can appreciate this is frustrating and we apologise for any inconvenience caused. 

 

Could you please expand on what your current set up is? Are you using any secondary equipment currently? 

 

I've managed to locate your account and I can see you spoke with the team and a reboot was requested. Has this helped things? I can't see any issues on our end currently that could be causing this. 

 

Thanks, 

Sofia
Forum Team



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ToffeeSurprise
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Re: Can you fix bufferbloat on VM?

Modem mode does nothing, it's inherent to DOCSIS and regardless of what you do that data gets fired through the DOCSIS chipset. Until VM rolls out low latency DOCSIS, and don't hold your breath on that any time soon.

Fulted
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Re: Can you fix bufferbloat on VM?

Hi, thanks for the response. 

At the moment it's just a Superhub 3 with 15m Cat7 cable going directly to my PC for gaming. I was only going to invest in a new router if it could help the bufferbloat issue. 

Previously on TalkTalk where I had better bufferbloat but much lower download speed. Virgin Media was already installed previously for the tenant who lived here so it was just a matter of "plug and play", but I'm unaware if they ever had problems.  

The reboot was done manually by logging into the router settings which didn't seem to change anything. Like stated in the original post, switching the router to modem mode and having only my PC connected did not change the result of the speed test (the speeds are fine ranging from 340-380 down/32-38 up). 

 

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Fulted
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Re: Can you fix bufferbloat on VM?

Yes I had heard it's a difficult time for VM in regards to the whole latency issues, regardless of how good the ping reads.

Somewhere someone had mentioned trying modem mode to see if it improved anything at all and if it did, a new router that supports SQM could be beneficial. As you've just said, it did nothing. Unfortunately my knowledge on the matter is next to nothing so it was worth the try.
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ToffeeSurprise
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Re: Can you fix bufferbloat on VM?

Honestly, too many people suggest modem mode as a magical fix for all sorts of issues. Modem mode actually has fairly limited use cases, it's for power users who would rather offload some Superhub functionality like DHCP or WiFi over to a device of their choosing. Offloading WiFi isn't a bad call, considering Virgin Media's routers have the stupid decision to constantly reboot if the connection goes down, nuking your WiFi. I digress.

Anything to do with QoS is basically pointless, Virgin Media will completely ignore any markings you throw at it and apply their own policies to protect their network and services (no funny ideas about marking all your traffic as EF). So all you'd do is get a router to apply a QoS policy which gets completely ignored when the traffic reaches the SH or headend. If you're having congestion issues on your LAN before it even gets to the router then you have other problems to deal with.

The way I solved bufferbloat was by switching to FTTP, which despite a technically slightly slower connection speed resulted in a massive increase in performance. Otherwise it'll be a long wait for VM to implement low latency DOCSIS which will no doubt happen eventually but they won't exactly be in a rush.

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legacy1
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Re: Can you fix bufferbloat on VM?

Bufferbloat and available bandwidth is a complicated thing but can QoS on a router help Bufferbloat? Yes if done right this is what I get with a ZyXEL VPN300
https://www.waveform.com/tools/bufferbloat?test-id=283db353-2e61-40be-a2df-44420b2c8d97

So you need to set download limit to -10Mb of your download speed (100Mb on VM is 112Mb) and - 0.9Mb on the upload.

This all works fine as long as the available bandwidth is there I think VM QoS the downstream well before it gets to the hub which its rate limiting can buffer but upstream is a problem when the available bandwidth is not there so you buffer in the hubs non-QoS limiter.

The buffer sizes in the hub when the available bandwidth is there is better the faster you go the slower package you go without QoS and just let the hub rate limit you the more bufferbloat there is.

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keasy
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Re: Can you fix bufferbloat on VM?

Upgrade to 1Gig and alleviate the need for QoS all together. 

 

Or buy a router and as a rule set it to 10% to 20%  beneath your upload and download speeds.

Personally I'd recommend something that handles CAKE. The latest ASUS RT AX86U with custom Merlin firmware allows you to set your overhead to DOCSIS and enable CAKE. 

Though if you do upgrade CAKE is rendered useless above ~400mb  as will most QoS. 

 

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