High ping via ethernet - Totolink X5000R

Hello. I'm new here - sorry if I'm miss something important.

First of all my ISP theoretically offer me 500/25 Mbit/s connection speed. I got Totolink X5000R and on the stock firmware ping (or maybe bufferbloat as well) is ok. Actually it is good enough to handle video-conference with ~10persons (which is not big surprise for me).

After switching to (clean installation of) OpenWrt 21.02.2 (r16495-bf0c965af0) I got problems with those conferences (my voice is deformed etc.). Google says find out this SQM. Now I think bufferbloat is not my main problem. It is unstable ping even on unloaded connection.

My configuration is DOCSIS Cable -> ISP Router (acting as a bridge) -> Ethernet -> Totolink X5000R -> Ethernet -> Laptop (only device connected to X5000R). For now I'm thinking that ISP router is not a problem, because Totolink with stock firmware working fine but I could measure ISP router's ping if needed as well.

Speaking about measurements:

  1. Totolink X5000R with stock firmware:
    a. https://www.waveform.com/tools/bufferbloat?test-id=8c414ce7-aef9-4902-85c1-9a65947556df
    b. https://www.waveform.com/tools/bufferbloat?test-id=14490ceb-8d0d-4964-8e11-0f6338ac7257
    c. https://www.waveform.com/tools/bufferbloat?test-id=59e65ea9-4b4b-45b5-84e9-8475a2a8af3a
    Max unloaded ping: 40.3 ms, max with download active: 591.6 ms
  2. Totolink X5000R with OpenWrt 21.02.2 (base line):
    a. https://www.waveform.com/tools/bufferbloat?test-id=8cee7c0a-dd59-4578-ae0f-945a2cfd4d5f
    Notice speed drops, max unloaded ping: 1176.1 ms, max with download active: 1378.3 ms
  3. Totolink X5000R with OpenWrt 21.02.2 + SQM:
    a. https://www.waveform.com/tools/bufferbloat?test-id=0d26acfd-21d8-4c05-87a8-1fdcfb1dcda3
    b. https://www.waveform.com/tools/bufferbloat?test-id=af30aa0c-e2dc-41ba-b153-710a673fc911
    c. https://www.waveform.com/tools/bufferbloat?test-id=46e652ff-91f3-48fd-9a12-de85a2eebbbc
    Max unloaded ping: 2380.3 ms, max with download active: 4843.9 ms
  4. Totolink X5000R with OpenWrt 21.02.2 + SQM disabled:
    a. https://www.waveform.com/tools/bufferbloat?test-id=e5a633b4-6ccf-4e6a-ade1-a5d8a8d16b28
    b. https://www.waveform.com/tools/bufferbloat?test-id=54aca266-fdc2-475e-867b-747af7a85f2f
    c. https://www.waveform.com/tools/bufferbloat?test-id=4bf8cbde-8275-43e1-9a68-f398c688ad97
    Max unloaded ping: 2138.1 ms, max with download active: 2099.8 ms

Ping from laptop to Totolink X5000R with OpenWrt:

Ping statistics for
    Packets: Sent = 96, Received = 96, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 2ms, Average = 1ms

Ping from Totolink X5000R with OpenWrt to openwrt.org:

root@OpenWrt:~# ping openwrt.org
PING openwrt.org ( 56 data bytes
64 bytes from seq=0 ttl=54 time=48.636 ms
64 bytes from seq=1 ttl=54 time=50.777 ms
64 bytes from seq=2 ttl=54 time=46.767 ms
64 bytes from seq=3 ttl=54 time=47.717 ms
64 bytes from seq=4 ttl=54 time=46.650 ms
64 bytes from seq=5 ttl=54 time=49.163 ms
64 bytes from seq=6 ttl=54 time=49.358 ms
64 bytes from seq=7 ttl=54 time=49.342 ms
64 bytes from seq=9 ttl=54 time=47.037 ms
64 bytes from seq=10 ttl=54 time=47.491 ms
64 bytes from seq=11 ttl=54 time=50.650 ms
64 bytes from seq=14 ttl=54 time=46.712 ms
64 bytes from seq=15 ttl=54 time=47.829 ms
64 bytes from seq=16 ttl=54 time=46.757 ms
64 bytes from seq=19 ttl=54 time=46.875 ms
64 bytes from seq=20 ttl=54 time=46.608 ms
64 bytes from seq=21 ttl=54 time=48.997 ms
64 bytes from seq=22 ttl=54 time=47.015 ms
64 bytes from seq=25 ttl=54 time=48.663 ms
64 bytes from seq=26 ttl=54 time=47.884 ms
64 bytes from seq=27 ttl=54 time=49.000 ms
64 bytes from seq=28 ttl=54 time=48.982 ms
64 bytes from seq=29 ttl=54 time=46.965 ms
64 bytes from seq=31 ttl=54 time=50.080 ms
64 bytes from seq=32 ttl=54 time=46.812 ms
64 bytes from seq=33 ttl=54 time=49.125 ms
64 bytes from seq=34 ttl=54 time=47.329 ms
64 bytes from seq=35 ttl=54 time=49.398 ms
64 bytes from seq=36 ttl=54 time=47.002 ms
64 bytes from seq=38 ttl=54 time=47.669 ms
64 bytes from seq=39 ttl=54 time=47.614 ms
64 bytes from seq=40 ttl=54 time=49.057 ms

Traceroute from Totolink X5000R with OpenWrt:

root@OpenWrt:~# traceroute openwrt.org
traceroute to openwrt.org (, 30 hops max, 38 byte packets
 1  *  *  *
 2 (  11.704 ms  8.520 ms  9.671 ms
 3 (  11.554 ms  9.791 ms  10.207 ms
 4 (  9.907 ms  12.454 ms  13.876 ms
 5 (  10.582 ms  9.504 ms  10.614 ms
 6 (  41.627 ms  45.414 ms  43.820 ms
 7  *  *  *
 8  *  *  *
 9  *  *  *
10  *  *  *
11  wiki-01.infra.openwrt.org (  47.034 ms  *  48.593 ms

My SQM config:

root@OpenWrt:~# cat /etc/config/sqm

config queue 'eth1'
        option qdisc 'cake'
        option script 'piece_of_cake.qos'
        option interface 'wan'
        option debug_logging '0'
        option verbosity '5'
        option overhead '44'
        option linklayer 'ethernet'
        option enabled '1'
        option download '370000'
        option upload '20000'

As you can see connection became much more unstable after installing OpenWrt. I searched forum, and got topic like High Ping, High Packet Loss with UDP Streams, High latency/pings with VLAN interfaces and wifi - #11 by DjiPi, Raspberry Pi 4 drops packets and high ping with SQM. But they are connected to WiFi or ISP problems which I think is not my case.

  1. Disable Hardware flow offloading and Software flow offloading.
  2. The CPU of that router cannot handle more than 100-150MB if you use CAKE in SQM.

Techdata: TOTOLINK X5000R

    Brand: TOTOLINK
    Model: X5000R
      CPU: MediaTek MT7621AT
CPU Cores: 2
  CPU MHz: 880