R3 Congestion Control not working correctly + Ping Optimizer causes instability (Zen PPPoE)

[coffeehouse]

 

Hello Fraser / NetDuma Team,

I would like to report a possible R3 firmware/DumaOS issue. I have spent a long time testing different configurations, and I believe this may not be a normal setup problem.

Network setup:

• Router: NetDuma R3

• ISP: Zen Internet FTTP

• Connection type: PPPoE

• Speed: 900 Mbps download / 100 Mbps upload

• Firmware: DumaOS 4.0.540

Main issue:

The Congestion Control function appears to have little or no effect.

I manually changed the percentages (10%, 20%, 50%, etc.), but the Bufferbloat results do not change. It feels like QoS is not actually applying the limits.

I have already tested:

• IPv6 disabled

• SmartBOOST ON and OFF

• Speed Test Bypass ON and OFF

• Congestion Control mode set to Always

• Different Congestion Control percentages

• Different Ethernet cables

• R3 as main router

• R3 as secondary router behind Zen router

The result is basically the same.

Another problem:

When running Ping Optimizer, sometimes the R3 loses Internet connection completely. After several reboots it recovers.

After recovery, the built-in R3 Speed Test sometimes becomes abnormal:

• Normally around 900 Mbps download

• After the issue sometimes only around 500 Mbps download

Strange behaviour:

Sometimes without changing any settings:

• Bufferbloat suddenly becomes Grade A

• Speed Test returns to normal

• Everything works correctly

Then later, without any changes, the problem returns again.

Additional observation:

When R3 is used as a secondary router, the Speed Test ping was previously around 5–6 ms.

After the recent instability, the same setup now shows around 7–8 ms consistently.

I mainly use the R3 for competitive gaming (eFootball), so consistent latency and stable QoS performance are very important.

Could you please advise:

1. Is this a known PPPoE/QoS issue?

2. Could Congestion Control be failing internally?

3. Is there any Diagnostic Log I can provide?

4. Is there an Early Access/Beta firmware available that I could test?

I am happy to test firmware versions and provide feedback if it helps identify the issue.

Thank you very much.

[Netduma Fraser]

There can be issues with PPPoE sometimes so if possible I'd suggest having the other router handle it, put the R3 then in the main router DMZ to ensure you don't have any NAT issues then connect ALL devices to the R3 and see if Congestion Control works better then. Ping Optimizer can be inaccurate so I wouldn't trust the values all the time, also by design it disconnects devices to ensure they don't interfere with the test, when finished they would reconnect. There are logs in Settings > Advanced > Troubleshooting.

I've given you Early Access so you can try the firmware there: https://forum.netduma.com/topic/60946-new-r3-firmware-dumaos-401147/

[Rodolfo Lima]

On 31/07/2026 at 04:51, Netduma Fraser said:

Às vezes, podem ocorrer problemas com PPPoE, então, se possível, sugiro que você deixe o outro roteador cuidar disso, coloque o R3 na DMZ do roteador principal para garantir que não haja problemas de NAT e, em seguida, conecte TODOS os dispositivos ao R3 e veja se o Controle de Congestionamento funciona melhor. O Otimizador de Ping pode ser impreciso, então eu não confiaria nos valores o tempo todo. Além disso, por padrão, ele desconecta os dispositivos para garantir que não interfiram no teste e, ao terminar, eles se reconectam. Os registros estão em Configurações > Avançado > Solução de Problemas.

Eu lhe concedi acesso antecipado para que você possa experimentar o firmware aqui:  https://forum.netduma.com/topic/60946-new-r3-firmware-dumaos-401147/

É melhor dhcp e por o R3 na dmz do que usar pppoe no R3?

[Netduma Fraser]

19 hours ago, Rodolfo Lima said:

É melhor dhcp e por o R3 na dmz do que usar pppoe no R3?

DHCP & DMZ would be my recommendation if you still have issues with PPPoE

[Redflame]

On 7/31/2026 at 8:04 AM, coffeehouse said:

 

Hello Fraser / NetDuma Team,

I would like to report a possible R3 firmware/DumaOS issue. I have spent a long time testing different configurations, and I believe this may not be a normal setup problem.

Network setup:

• Router: NetDuma R3

• ISP: Zen Internet FTTP

• Connection type: PPPoE

• Speed: 900 Mbps download / 100 Mbps upload

• Firmware: DumaOS 4.0.540

Main issue:

The Congestion Control function appears to have little or no effect.

I manually changed the percentages (10%, 20%, 50%, etc.), but the Bufferbloat results do not change. It feels like QoS is not actually applying the limits.

I have already tested:

• IPv6 disabled

• SmartBOOST ON and OFF

• Speed Test Bypass ON and OFF

• Congestion Control mode set to Always

• Different Congestion Control percentages

• Different Ethernet cables

• R3 as main router

• R3 as secondary router behind Zen router

The result is basically the same.

Another problem:

When running Ping Optimizer, sometimes the R3 loses Internet connection completely. After several reboots it recovers.

After recovery, the built-in R3 Speed Test sometimes becomes abnormal:

• Normally around 900 Mbps download

• After the issue sometimes only around 500 Mbps download

Strange behaviour:

Sometimes without changing any settings:

• Bufferbloat suddenly becomes Grade A

• Speed Test returns to normal

• Everything works correctly

Then later, without any changes, the problem returns again.

Additional observation:

When R3 is used as a secondary router, the Speed Test ping was previously around 5–6 ms.

After the recent instability, the same setup now shows around 7–8 ms consistently.

I mainly use the R3 for competitive gaming (eFootball), so consistent latency and stable QoS performance are very important.

Could you please advise:

1. Is this a known PPPoE/QoS issue?

2. Could Congestion Control be failing internally?

3. Is there any Diagnostic Log I can provide?

4. Is there an Early Access/Beta firmware available that I could test?

I am happy to test firmware versions and provide feedback if it helps identify the issue.

Thank you very much.

I’m a fellow Zen user. 900/105, Open reach. I wouldn’t trust ping optimiser too much. One time it told me 7ms like yourself, the second run said my ping was perfect at 100ms. I’ve managed to get a+ manually. I’m using pppoe but also found fritzbox, I found fritzbox in middle wasn’t ideal.

Before testing make sure house is quiet and no downloads are taking place. 

I would suggest the following:

1)) I strongly recommend going in and switching your mtu/enter in 1492. I had lag and changed only mtu and it improved things. 

2)) Hardwired into your R3 - go to Speedtest.net and pick zen from the test servers, do about 3. Go to Speedtest on dumaos admin page > click on three dots > advanced > manually enter the avg download and upload.  

3)) Either going to router web admin address or Duma os mobile app. Open up ping optimiser and pick advanced (three dots and advanced again). Scroll down to the congestion control part, click on that you’ll see sliders. 

4)) Then open another page on a pc/laptop/series x wired into R3. Google bufferbloat test. Pick waveform option. Starting at 95 and test. Then go down by 10 until you get no added lat. When you get good result, they advise to go up by 5 percent to see if you keep result.

5)) After getting no added lat, I usually do a test via wired device on Speedtest.net and fast.com to note that cc is holding up. Speedtest.net usually shows lat on all bits idle, download and upload. Fast.com will show 10ms unloaded and 15ms loaded.

6)) I would like to add that say 85 down and 90 up on cc, could look great on paper A+ no added latency but doesn’t feel great in game.