Bufferbloat from ISP "burst"

Ever since changing ISPs internet feels like shet...

I used to have no bufferbloat with previous ISP 75Mbps up / 150 Mbps down... ( I didn't do the bufferbloat test but at least ping NEVER spiked above 1-3ms in speedtest.net ... )

Afrer switching it's hell - 150 Mbps up / 300Mbps down yet I can't even do ANY benchmark without ping spiking all the way past 300ms... ( In gaming this shows up as very random +50ms spikes, lasting for couple of seconds before going away - lots of micro stutter as well , like rubber banding back and forth ever so slightly but this one Idk , could be attributed to bad servers on this particular game... )

Anyways, why is this happening? My guess is there is this thing called "burst" - where for very short duration ISP let you get past their download/upload limits ? I guess to mitigate the ping spikes? But it's this very thing that's causing all of them spikes?!

If test isn't already abysmal with +60ms on upload then if you scroll down to maximum ping it gets even worse... both are spiking well above 300ms every time ISP deems fit to initiate their "boost" thing :

Router seems to fall apart when this happens , download speed jumps past 350Mbps - like rapidly starts climbing all the way up to 650Mbps for a second or two but then it rapidly descends even faster ... down to below 100Mbs in a blink ( this is when ping gets destroyed ) ... Idk what they are even thinking... Who does this help?
I did some testing :

  • Software/Hardware offload and no offload - Basically all suck... Upload bufferbloat is +60ms regardless of what offload is in use... it does have some differences tho - with no offload there are no ping spikes where max ping is over 100ms ( or happens very rarely) but the median ping is quite worse - this can be improved with some offloading , median ping gets reduced but I start seeing ping spikes of above 300ms whenever ISP does this thing... ( These show up in every benchmark run... While with no offload maybe every 10th run? )

  • SQM with no offload - no ping spikes , median is as good as hardware offload - looks great! The only issue? It seems to be broken... My router is too weak... Can handle only up to 120Mbps Up/Down ( I tried lowering download from 240Mbps to 200Mbps but nope , only goes as far as 120Mbps )

    Screenshot from 2023-03-30 02-41-50

Is there any way to handle this without SQM? Like idk, some permanent throttling of interfaces such that devices can't go above and beyond 300/150Mbps ( Triggering that ISP burst behavior )

I did try setting download speed to 0 in SQM hoping it would let it pass through without issue but this breaks download latency... Site reports +20ms download bufferbloat

I think you've discovered the answer: using SQM will solve the bufferbloat, but you don't want to buy a more powerful router to handle your ISP speeds. I offered this advice on another post:

You could ask your ISP to decrease your speed to the point the router can do SQM and see if your gaming improves. You save money both ways: no new router and lower monthly payments. Good luck!

At least not now... but yeah I am thinking about it

Do you think there's a way of distributing SQM load across my dumb APs?

My network looks like this

  • One main router which creates LAN out of WIFI and LAN port1

  • Guest LAN interface on this main router - using LAN port2 to connect to multiple access points ( All of them are dumb APs - DNS and DHCP are assigned by main router )

Anyways... Do you think I could improve performance by lets say I SQM only LAN on main router - using SQM on dumb APs themselves to manage Guest LAN

Could that net me a better performance somehow? ( I'd test ideally but can't really until later )

I don't know how if at all they'll be able to coordinate latency wise - like what packet goes first , but at least bandwidth should be higher and less load on the main router itself?

Idk... short of this I am thinking of calling ISP to check if they can somehow disable this burst behavior? ( I am not sure if this is even causing bufferbloat )

I suspect not. SQM needs to run at the "botteneck link" - that is, the slowest link in the network. That's usually your connection to your ISP.