Why is SQM QoS limiting my download speed?

Hi there,

I simply want to limit my upload on my network to reduce bufferbloat but my download is being limited now too despite having it set to 0, even when set to 90% of my maximum downstream it throttles to 450 KB/s- which doesn't make any sense to me.


My max download is 110 Mbps down / 10 up.


Are you sure that eth0 is the upstream wan interface?
(and not the LAN interface)

If you set SQM for the LAN interface, the direction logic is naturally inverted. (egress means "from router towards LAN" = in practice "download from WAN forwarded to LAN")

What @hnyman said; this is easy to check empirically, just set Upload to 0 and Download to 5000. If this fixes things eth0 is not the wan interface.
To add to that on routers that use a WAN port that belongs to a switch and that use VLANs to shuttle between the switch's WAN port ad the switch's LAN ports instantiating sqm on the "raw ethernet" interface will shape both directions to the minimum specified. So please check whether your WAN interface might be something like eth0.1 and the CPU switch port might be eth0.2.

Best Regards

@moeller0 @hnyman - I have always looked at the Network -> Interfaces page to identify the WAN interface. Is this generally good advice?

LEDE WAN interface

Not that I am an expert in this, but this is pretty much what I do as well...

That works.

And naturally it is also said the actual network config file...

config interface 'lan'
        option type 'bridge'
        option ifname 'eth1.1'
        option proto 'static'
config interface 'wan'
        option ifname 'eth0.2'
        option proto 'dhcp'

E.g. in my R7800, LAN is eth1.1 and WAN is eth0.2

In the current LEDE master, it is typically a "dotted" tagged interface, not just plain eth0

Thinking of it, I believe @jow or @nbd recently explained that LUCI reports that interface as wan thsat carries the deualt route. So:
netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default UG 0 0 0 pppoe-wan * UH 0 0 0 pppoe-wan * U 0 0 0 br-lan * U 0 0 0 eth1.2

would indicate (at least to me, but I am not an expert) that wan should equal pppoe-wan, which is exactly what is reported under Network -> Interfaces as wan...