Bufferbloat related censorship at Virgin Media

Jack Bates jbates at paradoxnetworks.net
Mon Mar 2 00:39:29 UTC 2015

On 3/1/2015 6:14 PM, Dave Taht wrote:
> It is 100% possible to fix excessive downstream buffering from some
> misconfigured device with a shaper on the download  *on the CPE or
> home router*.
 From OP: "However I've recently noticed periods of 500-800ms latency to 
the CMTS gateway when only using 15-20 of the 60Mbps total (and little 
to none upstream utilisation)."

I agree with you that it is better to run a shaper that insures your 
shaper hits saturation and handles queue policies before the upstream 
does. That is great if it is your pipe (and only its queue) that is 
saturating. I don't think this problem qualifies.

I find it difficult to believe that he's hitting a buffer bloat issue on 
a single (not shared with others) queue using 1/3rd of the total 
bandwidth available to him at those speeds and with that latency value. 
His problem is more likely lower down (unable to obtain max speed 
resulting in saturation) or a shared queue where others are saturating 
it and him applying a shaper will not keep others from doing so.


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