Tp link archer c7 ac1750 limit UDP packets with PFIFO

oops im not sure now if i have it yet sorry again

heres my mesage
does this look ok or is it still not working

root@OpenWrt:~# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo state UP qlen 1000
link/ether 50:d4:f7:14:f0:a3 brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
link/ether 50:d4:f7:14:f0:a2 brd ff:ff:ff:ff:ff:ff
4: wlan1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
link/ether 50:d4:f7:14:f0:a3 brd ff:ff:ff:ff:ff:ff
5: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
link/ether 50:d4:f7:14:f0:a3 brd ff:ff:ff:ff:ff:ff
6: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-lan state UP qlen 1000
link/ether 50:d4:f7:14:f0:a3 brd ff:ff:ff:ff:ff:ff
7: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
link/ether 50:d4:f7:14:f0:a4 brd ff:ff:ff:ff:ff:ff
root@OpenWrt:~#

You're going to have to understand a bit about your router before going ahead.

It looks like your "WAN" interface is eth0.2. If so that is what you'd need to modify.

man tc on a "desktop" Linux machine, or on the web, will help you understand what qdisc is installed and how it is behaving. For example, http://man7.org/linux/man-pages/man8/tc.8.html

Understanding add/change/replace as well as show will be needed to modify the settings and confirm them.

Yeh my wan etho.2 in tnterface
Yeh ive used a few of those settings and understand a few commsands from wathing videos and reading abou them

So i think your saying i havent installed it yet

More that “it’s in your hands now”, especially as your approach is “rather unique”.

That seems rather roundabout to achieve low latency, but in the spirit of encouraging experimentation I would recommend to use bfifo instead of pfifo, as queue size in bytes is better correlated with transmission time than packet count as packet size ranges from around 64 to around 1500 bytes, typically.
You could also experiment with setting fq_codel's interval parameter to less than the default 100ms if you want tighter control.
Going for really short buffers without meaningfull AQM will certainly cut down on queueing delay, but at the cost of increased packet loss and reduced throughput.

Please run tc -s qdisc and tc -d qdisc to see what "limit" your pfifo instances use.

Also note that you can use sysctl to set/change the default qdisc in your sytem:
sysctl net.core.default_qdisc will show the current default, sysctl -w net.core.default_qdisc=bfifo will change that default. To make changes persistent over booting you could also simply add
net.core.default_qdisc=bfifo to /etc/sysctl.conf (or create that file if it does not exist yet). Whether pfifo/bfifo are reasonable defaults for your use-case is a different question, and one you can explore yourself.

1 Like

Please note that that user also uses SQM on the wan port...
https://forum.netduma.com/topic/11538-possible-fix-for-lag-compbufferbloat/?do=findComment&comment=93657
"Wow, I took your advice and implemented sqm to the wan interface, I kept pfifo qdisc for lan Ethernet and wireless and the game plays even better, I had a really bad lobby where evryones ping was going up and down and still managed 36 -6, even melting shot gunners lol, think we may be on to something here, thanks for the advice."

i typed this and heres the results

oot@OpenWrt:~# tc -s qdisc
qdisc noqueue 0: dev lo root refcnt 2
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
qdisc pfifo 8001: dev eth0 root refcnt 2 limit 1000p
 Sent 848778463 bytes 1029649 pkt (dropped 0, overlimits 0 requeues 1)
 backlog 0b 0p requeues 1
qdisc noqueue 0: dev br-lan root refcnt 2
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
qdisc noqueue 0: dev eth0.1 root refcnt 2
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
qdisc pfifo 8002: dev eth0.2 root refcnt 2 limit 3p
 Sent 480019199 bytes 453201 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0

root@OpenWrt:~# tc -d qdisc
qdisc noqueue 0: dev lo root refcnt 2
qdisc pfifo 8001: dev eth0 root refcnt 2 limit 1000p
qdisc noqueue 0: dev br-lan root refcnt 2
qdisc noqueue 0: dev eth0.1 root refcnt 2
qdisc pfifo 8002: dev eth0.2 root refcnt 2 limit 3p

you are correct i forgot to mention i will run fq codel on wan as well
like it show on that link you read i wanna set it up the exact same way
as its been a long time ago that thread was written
and i always wanted to try the exact same setup for myself

to me it looks like pfifio is set up on my wan i think
but you guys know best
as i typed this in yesterday
tc qdisc add dev eth0.2 root pfifo limit 3
so i think may have worked

and

Indicate you got the desired configuration, How much this is going to help given:

, especially the qlen 1000 part, is a different question.

i think i only limited the packet size not the packet length lol

i am learning thought trial and error lol

i just wanted to as this question as well if i wanna reset my router back to when i first instaled openwrt so i get rid of alll the coommands i typed in
would thia comand do the trick i know it gets rid of the software i downloaded on router
this here firstboot && reboot now