S5120-52C-PWR-EI : Port poe off: underload state

[ferdo]

Hi,

On my S5120-52C-PWR-EI, PoE ports fall with "Port poe off: underload state" message in the log,. What causes the crash of connected phones.
Can anyone tell me how to fix it.
Similarly, when I restart my S5120-52C-PWR-EI, connected phones fail to connect to the IPBX without disconnecting and reconnecting.
I need help please.

Regards

Ferdo

[Vince_Whirlwind]

The "Underload State" message is probably a symptom of the problem, not its cause. You should probably look at the power device itself for the problem, as the switch is simply reporting on the power that device is drawing.

For your second question, you may need to provide more detail - are you saying that after you have rebooted the switch, the phones come back up unconnected and you have to do something manually for them to reconnect?

Perhaps you have the edge ports on auto admin edge but the uplink port comes up much slower?

[ferdo]

Hi Vince_Whirlwind,

Thank you very much for your reply.

I do not quite understand what you said about my first question. Do you mean that my switch has no sufficient power?
When a port falls the LOG displays the following message:

GigabitEthernet1/0/12:  Port poe off: underload state ,rawstatus=0x1e.

I also did not quite understand your answer to the second question. I enable the spanning tree edged-port ( stp edged-port enable) on all ports connected to phones. Is this the cause ? Should I disable it ?

Thank you for your help

Regards

Ferdo

[Vince_Whirlwind]

1/ No, I would interpret that as meaning the device was drawing less than the standard amount. Check your power budget just to make sure, though.

2/ You need the edged-port so that when a phone is disconnected/reconnected, it comes up quickly.

When you reboot the switch (which shouldn't happen very often - many switches should be able to run for years without reboots), the edge ports are coming up faster than the uplink port, so the phones can't communicate with their DHCP/provisioning server.

I just had a look in the 5120 command reference and I couldn't see an "uplink fast" option for this switch type, so for a reboot of the switch, you may be stuck with having to configure all the edge ports as down and then up again after you perform any reboot.

[ferdo]

Hi Vince_Whirlwind,

Thank you very much for your answer. On each 5120 - 48 ports, 42 ports are used to connect my Aastra IP phones. It seems that the number of phones per switch must not exceed 24. Is this true ? What do you think about ?

When I want to set the poe port priority to "critical", only 24 ports can be set to "critical". For other ports, the switch displays a message indicating that there is not enough power for the remaining ports.

Thank you

Regards

Ferdo

[Vince_Whirlwind]

It depends what PoE class your Astra phones are.

Your 5120 has 370 Watts, which is enough for 48 Class I or Class II phones, or 24 Class III phones, unless you've added an RPS in which case you can have 48 Class III phones on it.

[ferdo]

Hi Vince_Whirlwind,

Thank you very much

Regards

Ferdo

[Vince_Whirlwind]

Sometimes even though a phone might be Class II, the switch will allocate Class III power to it, eating up too much of your power budget.

You can force a port's poe settings to a particular class if that happens.

[liorski]

Sir I have a problem with the HP SWITCH S120. When I turn on the switch it automatically off. Can I have a solution for my problem?

Thank you very much