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Message 1 of 3

Smart Hub 2: Appalling F score on bufferbloat test

My BT Smart Hub 2 router gets an appalling F rating on the Waveform bufferbloat test.

I have a BT broadband fibre-to-the-cabinet package and a 35 Mbps download speed.

I understand that in order to fix this bufferbloat issue, you need to have or install Smart Queue Management (SQM) on your router; but the Smart Hub 2 does not have SQM, and it cannot be adapted to run SQM.

Why did BT not consider incorporating SQM software into their router? I am sure this would have been very straightforward, and would have resulted in superior router performance for no extra cost.

Would this bufferbloat improve if I had a much faster BT full fibre broadband (fibre-to-the-premises), or would the bufferbloat still remain even with full fibre?


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Message 2 of 3

Re: Smart Hub 2: Appalling F score on bufferbloat test

Are you using Ethernet or WiFi? Are lots of other devices using your internet at the same time?

That website is not measuring the bufferbloat to your router, it is measuring the bufferbloat to your connected device. Even via Ethernet there are variables that can affect the connection between you and the router.

The upgrade to FTTP does carry benefits, one of which is improved reliability compared to copper connections. Please don't read this as me saying it will give you a better bufferbloat score though. 

For what it's worth I'm on FTTP 500 and I get a great score of usually A or B, this is using 5ghz WiFi with a strong DFS channel provided by a 3rd party WiFi 6 router connected to my SH2.  If I drop down to 2.4ghz I get a much worse score of D-F.

So it seems to be a very sensitive score that is affected by lots of variables. (Yes even when using Ethernet) If you are not noticing any problems with your connection, I would not pay attention to it.

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Message 3 of 3

Re: Smart Hub 2: Appalling F score on bufferbloat test

Thanks very much for your reply.

I am using a 2012 Mac Mini computer directly connected to the Smart Hub 2 by Ethernet.

I tested with the router WiFi switched off, and my Mac Mini as the only device connected to the router. During the bufferbloat test, there were no other apps or webpages running on the Mac. I tried this bufferbloat test in more than one browser, and got a score of F in all browsers.

Before switching to BT FTTC broadband recently, I had a Plusnet ADSL broadband, with about 20 Mbps download speed (my Plusnet ADSL was quite fast as I live close to the telephone exchange).

I had some problems with bufferbloat when I was with Plusnet, and to solve this, I bought a second hand BT Home Hub 5 router with OpenWRT third party firmware pre-installed. With this OpenWRT setup, I was able to install a Smart Queue Management package, and this completely fixed my bufferbloat issues, and it got me an A rating on the Waveform bufferbloat test. 

But even when using a standard Home Hub 5 with standard BT firmware, I would still get a B rating on the Waveform test, when I was with Plusnet. 

So I am surprised that after upgrading to the Smart Hub 2, and upgrading to BT broadband with a faster download speed of 35 Mbps, my bufferbloat rating has got much worse, dropping down to an F.

The bufferbloat problem I had with Plusnet manifested when we had visitors to the house for social events or celebrations, taking lots of pictures with their smartphones. 

As they took pictures, and as these pictures were automatically uploaded from the smartphones to the cloud, this would seize up my router: under these conditions, it would take a minute or two for a webpage to load in a browser. My Plusnet ADSL upload speed was less than 1 Mbps, so it would take a long time for the pictures to upload.

So any time I had visitors around taking pictures, bufferbloat would often render browsing the web very slow. Once I switched to the OpenWRT firmware on the Home Hub 5, this slow page loading issue was completely resolved. 

I have not yet had visitors around for a celebration since changing to BT broadband and the Smart Hub 2, so I do not know if this bufferbloat issue will reappear when these visitors take lots of pictures. 

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