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Tplink AX55 V1 firmware 1.5.11 massive bufferbloat

Tplink AX55 V1 firmware 1.5.11 massive bufferbloat

Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Tuesday - last edited 15 hours ago
Tags: #Network Connectivity #Firmware Update #Bandwidth Control/QoS #HomeShield
Model: Archer AX55  
Hardware Version: V1
Firmware Version: 1.5.11

Just wanted to report an issue after updating my Archer AX55 V1 to firmware 1.5.11.
 

Right after the update, everything seemed fine. But once I enabled QoS, the router basically became unusable.
 

What I’m seeing:

  • Massive bufferbloat as soon as QoS is on

  • CPU usage spikes straight to 100%

  • RAM usage looks normal

  • Ping jumps from a stable ~49 ms to 290 ms+

  • Web UI becomes extremely slow and at times I can’t even log in to the router
     

Disabling QoS immediately brings things back to normal, so the issue seems directly tied to QoS behavior on 1.5.11.
 

This wasn’t happening on the previous firmware with the same settings and same network load.
 

Has anyone else on AX55 V1 experienced this on 1.5.11?
Any known fixes, or is this a confirmed firmware bug?

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#1
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1 Accepted Solution
Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat-Solution
Wednesday - last edited 15 hours ago

Hello @Retro_0223 ,

Welcome to our community.

 

Besides firmware updates, have you changed any other settings?

 

May I know if your network topology diagram is as follows:

ISP modem—AX55)))((( client devices

(Note: — stands for wired connection,)))((( stands for wireless connection )

 

The tech team has been made aware of your case; they will likely reach out to you via email to continue troubleshooting. Please check your email inbox and confirm.

Welcome to Our Community！ Check Out the Latest Posts: △New Firmware for Archer BE800 V1 to Support VPN Merge, EasyMesh Guest/IoT Network Extend, and More △Enhanced EasyMesh Support with Extended Guest/IoT/MLO Networking and Advanced Features for BE550 V2 △New Firmware for Archer BE900 V2 to Support Multi-WAN, DoH/DoT, EasyMesh in AP Mode and More △New Firmware for Archer BE260/Archer BE400 to Support VPN Merge, New ECO Mode, and More If you found the post or response helpful, click Helpful. If an answer solves your problem, click Recommended Solution so that others can benefit from it.
Recommended Solution
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#2
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10 Reply
Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat-Solution
Wednesday - last edited 15 hours ago

Hello @Retro_0223 ,

Welcome to our community.

 

Besides firmware updates, have you changed any other settings?

 

May I know if your network topology diagram is as follows:

ISP modem—AX55)))((( client devices

(Note: — stands for wired connection,)))((( stands for wireless connection )

 

The tech team has been made aware of your case; they will likely reach out to you via email to continue troubleshooting. Please check your email inbox and confirm.

Welcome to Our Community！ Check Out the Latest Posts: △New Firmware for Archer BE800 V1 to Support VPN Merge, EasyMesh Guest/IoT Network Extend, and More △Enhanced EasyMesh Support with Extended Guest/IoT/MLO Networking and Advanced Features for BE550 V2 △New Firmware for Archer BE900 V2 to Support Multi-WAN, DoH/DoT, EasyMesh in AP Mode and More △New Firmware for Archer BE260/Archer BE400 to Support VPN Merge, New ECO Mode, and More If you found the post or response helpful, click Helpful. If an answer solves your problem, click Recommended Solution so that others can benefit from it.
Recommended Solution
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#2
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Wednesday

  @Joseph-TP thanks for the response.
 

Here’s my setup and what I’ve already tested.
 

Network topology
ISP router + modem combo provided by PLDT (Philippines), set to bridge mode
Archer AX55 V1 is in router mode and receives the CGNAT IP directly
Topology is: ISP modem (bridge mode) -> Archer AX55 -> client devices
 

WAN details
WAN type: DHCP
ISP advertised speed: 500 Mbps+ down / 500 Mbps+ up
Actual speed:
• QoS OFF: consistently 500 Mbps+ down and up, stable latency
• QoS ON (firmware 1.5.11): throughput drops anywhere between 30–310 Mbps, severe ping spikes and frequent timeouts

 

Behavior observed on firmware 1.5.11
• Massive bufferbloat immediately after enabling QoS
• CPU usage jumps to 100% as soon as QoS is enabled
• RAM usage remains normal
• Ping increases from a stable ~49 ms to 200–290 ms+
• Web UI becomes extremely slow and at times inaccessible
• Disabling QoS instantly restores normal performance
 

Troubleshooting already done
• Factory reset performed after updating to firmware 1.5.11
• Tested with default settings and only QoS enabled
• Issue occurs even with a single wired client connected
• No topology or configuration changes compared to the previous firmware
• Same network load and devices worked normally with QoS on the earlier firmware
 

The issue appears directly tied to QoS behavior in firmware 1.5.11 rather than configuration or topology. Everything works as expected as soon as QoS is disabled.

Let me know if you need logs, specific QoS settings screenshots, or if there’s a known regression or workaround for QoS on AX55 V1 firmware 1.5.11... Or my router is just faulty. 😵‍💫
 

Thanks.

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#4
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Wednesday

Hi @Retro_0223 ,

Please don't worry, it's likely related to the changes in version 1.5.11.

I will get back to you if there are any updates.

Welcome to Our Community！ Check Out the Latest Posts: △New Firmware for Archer BE800 V1 to Support VPN Merge, EasyMesh Guest/IoT Network Extend, and More △Enhanced EasyMesh Support with Extended Guest/IoT/MLO Networking and Advanced Features for BE550 V2 △New Firmware for Archer BE900 V2 to Support Multi-WAN, DoH/DoT, EasyMesh in AP Mode and More △New Firmware for Archer BE260/Archer BE400 to Support VPN Merge, New ECO Mode, and More If you found the post or response helpful, click Helpful. If an answer solves your problem, click Recommended Solution so that others can benefit from it.
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#5
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Thursday - last edited 15 hours ago

Hello @Retro_0223 ,

Please try this firmware and see if it helps.

Archer AX55_V1_1.5.11 Build 20260205(Beta Firmware) 

Welcome to Our Community！ Check Out the Latest Posts: △New Firmware for Archer BE800 V1 to Support VPN Merge, EasyMesh Guest/IoT Network Extend, and More △Enhanced EasyMesh Support with Extended Guest/IoT/MLO Networking and Advanced Features for BE550 V2 △New Firmware for Archer BE900 V2 to Support Multi-WAN, DoH/DoT, EasyMesh in AP Mode and More △New Firmware for Archer BE260/Archer BE400 to Support VPN Merge, New ECO Mode, and More If you found the post or response helpful, click Helpful. If an answer solves your problem, click Recommended Solution so that others can benefit from it.
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#6
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Yesterday

  @Joseph-TP 

Testing the beta firmware now. Will be using tomorrow in my daily tasks. I'll give feedback if everything's all good. 🙌

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#7
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Yesterday

  @Joseph-TP 

Looks like the beta firmware worked. UI is more snappy and no bufferbloats. Don't know what voodoo magic you guys did but that fixed it for now. 
Will continue to monitor. Speeds are within expectation as QoS is enabled. Cheers guys!

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#8
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
Yesterday

Hi @Retro_0223 ,

Sounds great~ Feel free to contact us if you have any further questions~!wink

Welcome to Our Community！ Check Out the Latest Posts: △New Firmware for Archer BE800 V1 to Support VPN Merge, EasyMesh Guest/IoT Network Extend, and More △Enhanced EasyMesh Support with Extended Guest/IoT/MLO Networking and Advanced Features for BE550 V2 △New Firmware for Archer BE900 V2 to Support Multi-WAN, DoH/DoT, EasyMesh in AP Mode and More △New Firmware for Archer BE260/Archer BE400 to Support VPN Merge, New ECO Mode, and More If you found the post or response helpful, click Helpful. If an answer solves your problem, click Recommended Solution so that others can benefit from it.
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#9
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
18 hours ago

  @Joseph-TP Hello, when will this update with the QoS fix be released to all users?smiley

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#10
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
18 hours ago

AIRL wrote

  @Joseph-TP Hello, when will this update with the QoS fix be released to all users?smiley

  @AIRL 

 

Hi,

 

Joseph-TP posted a link that is accessible by all users in post #6 above.

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#11
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Re:Tplink AX55 V1 firmware 1.5.11 massive bufferbloat
18 hours ago

  @woozle Yes, I've seen it, but it's a beta version, I'm waiting for the release.

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#12
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Network Connectivity Firmware Update Bandwidth Control/QoS HomeShield
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