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New Member

How POE switch will identify connected ip phone doesn,t have external power supply

Hi,

Plesae tell me

How POE switch will identify connected ip phone doesn,t have external power supply after connecting ip phone to the switch.and wht is the booting preoccess of the ip phone.

4 REPLIES
Hall of Fame Super Gold

How POE switch will identify connected ip phone doesn,t have ext

Re: How POE switch will identify connected ip phone doesn,t have

hello,

Is it a Cisco phone or  third party phone? what series switch?

1. The hardware cannot measure real time power consumption. It is whatever power the device asked for initially (for which the switch is budgeted).

  •       IEEE Device - based on class

  •       Cisco Device - based on CDP message

2. The device might actually be drawing more or less than the power allotted. The switch cannot monitor this. It only knows about the configured power.The only option is to display the PoE status for the specified PoE port or for all PoE ports with the show power inline user EXEC command.

3. If the switch detects a fault caused by an undervoltage, overvoltage, overtemperature, oscillator-fault, or short-circuit condition, it turns off power to    the port, generates a syslog message, and updates the power budget and LEDs.

The syslog message looks similar to this output:

    01:13:11: %ILPOWER-7-DETECT: Interface Fa0/10: Power Device detected: IEEE PD

    01:13:11: Ilpower PD device 3 class 3 from interface (Fa0/10)

    01:13:11: Ilpower deny interface(Fa0/10) because request power 15400 is greater than user config max 7500.

The 15400 is the amount of power requested by the device and the 7500 is the configured amount of power the switch can provide to the device connected to the port.

In this case, if the connected devices are non-Cisco then you are not able to use CDP. Therefore, if the device requests more power, then it is denied.

Hope that helps!

Thanks,

Karthik

Blue

How POE switch will identify connected ip phone doesn,t have ext

Hi

When a device is detected on a port, the switch sends a Fast Link Pulse (FLP) to whatever is plugged in. It waits to receive a response from the device. If the host device responds appropriately (aka. Has PoE requirements) the switch will

negotiate the power req's with the device and adjust power accordingly. If the device doesn't respond with a FLP, then power is never turned on.

Regards

Ronak patel

Regards Ronak Patel Rate all helpful post by clicking stars below the answer.
New Member

How POE switch will identify connected ip phone doesn,t have ext

Hi Karthik and Ronak,

Thankyou for your  Valuable Information....

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