LINK-3-UPDOWN: Interface FiveGigabitEthernet x/x, changed state to down(reason: Local Fault).

Wondering what is the cause for the frequent disconnection.
AP cable tested working multiple times but AP seems to always auto reboots by itself.
AP in use is
RAP73Pro.



System description      : Ruijie 10G Ethernet Switch(CS86-24MG4VS-UP) By Ruijie Networks
System start time       : 2025-02-27 18:29:53
System uptime           : 06:23:48:18
System hardware version : 1.10
System software version : CS86_RGOS 12.6(2)B0105
System patch number     : NA
System serial number    : G1SB1B7000029
System boot version     : 1.4.32(Master) 1.4.32(Slave)
System rboot version    : 1.1.60

17_Tuas_POE_2.5G_SW4#sh poe powersupply
Device member                   : 1
Power management                : energy-saving
PSE total power                 : 370.0 W
PSE total power consumption     : 97.2 W
PSE total remain power          : 272.8 W
PSE powered port                : 6
PSE disconnect mode             : dc
PSE reserve power               : 0%
PSE warning power               : 90%
PSE class lldp                  : enable
PSE uninterruptible-power       : enable

Dear sir,
Good day.
Have you tried change the power supply type? Like power the device by DC?
Have you checked the PoE standard that the RAP is currently using?
For RAP73PRO please make sure it's runing with the 802.3bt/at PoE.
You can check it in the RAP eWeb - Advance - PoE.
Best regards,
Lex

GTAC-Lex replied at 2025-3-6 21:18
Dear sir,
Good day.
Have you tried change the power supply type? Like power the device by DC?

Hi Lex,
The AP can only be powered by PoE++ switch as there is no alternative power source.
The RAP is currently forced to run on 802.3bt. It seems that AP will sometimes run as 802.3at (when we set as auto negotiation) even when we have sufficient POE power budget.

ICT Dept replied at 2025-3-7 08:29
Hi Lex,
The AP can only be powered by PoE++ switch as there is no alternative power source.
The R ...

Hi Lex,
I did further testing, it really seems like  RAP73PRO is an unstable product.
To ensure i am well under the PoE budget of the switch (370W).
I have only 9x   RAP73PRO connected to it now.

5x   RAP73PRO are hard set as   802.3bt (max drawing 51W x 5 = 255W)


Another 4x    RAP73PRO are hard set as   802.3at (max drawing 25.5W x 4 = 102W)




Total max power draw = 357W (under the switch PoE budget)




Based on this setting, i am still seeing link flapping on AP running on 802.3bt/at




Logs observed below from the switch CLI:
*Mar 7 10:44:50: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to down (reason: Local Fault).
*Mar 7 10:44:50: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to down.
*Mar 7 10:44:56: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:44:56: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:45:21: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to down (reason: Local Fault).
*Mar 7 10:45:21: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to down.
*Mar 7 10:45:26: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:45:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:45:50: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to down (reason: Local Fault).
*Mar 7 10:45:50: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to down.
*Mar 7 10:45:57: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:45:57: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:46:15: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to down (reason: Local Fault).
*Mar 7 10:46:15: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to down.
*Mar 7 10:46:21: %LINK-3-UPDOWN: Interface FiveGigabitEthernet 0/2, changed state to up.
*Mar 7 10:46:21: %LINEPROTO-5-UPDOWN: Line protocol on Interface FiveGigabitEthernet 0/2, changed state to up.

Can you advise what is the cause of these flapping?

ICT Dept replied at 2025-3-7 10:47
Hi Lex,
I did further testing, it really seems like  RAP73PRO is an unstable product.
To ensure  ...

Dear sir,

Good day.
In this case, we recommend that you specify the power supply protocol standard for the RAP instead of leaving it in auto to see if the situation improves. At the same time, judging from the logs on your switch, the port may be closed because the connected device (RAP) requires too much power. You can try to replace the power supply device and observe the test. We are sorry for the bad experience.

Best regards,
Lex

GTAC-Lex replied at 2025-3-7 11:10
Dear sir,

Good day.

Hi Lex,
I have tested and observed the logs :
Even hard setting the 2x APs to run as 802.3at, we are still seeing the flapping happening on switch CS86-24MG4VS-UP. By specification, this switch is supposed to support APs running on 802.3bt mode.
To also add, we have two units of CS86-24MG4VS-UP.
The same flapping is happening on the other switch that has APs hard setting as 802.3at.
I separately tested another RAP73PRO with fixed 802.3at setting to connect to a HPE switch (that supports up to 802.3at only). So far connection has been stable and we did not observe any flapping issues.
So is it conclusive that is issue resides with the switch power negotiation with the APs or something else that is causing the reboot?

ICT Dept replied at 2025-3-7 12:08
GTAC-Lex replied at 2025-3-7 11:10
Dear sir,

Hi, we recommend you to join us in our RITA live support to help you find the root cause regarding all the test you did.

Regards!