show power inline and show power command

Answered Question
Dec 18th, 2008

Hi every body!

I have few questions:

"Show power" shows a lot of informations. It also shows

PS TYPE WATT pS FAN STATUS

OUTPUT STATUS OPR STATE

What does" Ok" indicate in output status field?

"Show Power Inline" shows

interface Admin oper poer device

Does line code have Adminstrative mode?

What " auto" means under "Admin field" ?

thanks a lot!

I have this problem too.
0 votes
Correct Answer by Giuseppe Larosa about 8 years 1 month ago

Hello Sarah,

1) without CDP the switch can only detect there is a power over ethernet device on cable but canno adjust the power level and this can be a problem on high number of phones

2) CDP is also used to extend the QOS trust boundary to the ip phone and to instruct the phone on the vlan-id of the voice vlan and the CoS bits to use on sending voip frames this is needeed to provide end-to-end QoS.

CDP is also handy in troubleshooting to locate a phone and to see its model (defining a phone with the wrong model on CCM makes it unusable).

A standards based alternative to CDP named LLDP has been developed and can be used on newer IOS images to support third party ip phones.

For all the reasons stated above CDP or LLDP shoud be running all the time on the switch ports.

Hope to help

Giuseppe

Correct Answer by Mark Yeates about 8 years 1 month ago

Hello Sarah,

The OK status when you issue the "show power" command indicates that the power supply/fan are operating normally and there are no alarms or faults detected.

The administrative field indicates the amount of power configured for that port which is a configurable option. Auto (which is the default) on a PoE port will automatically detect the amount of power needed to power the connected device. Here is a link showing how to configure power for PoE port.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/command/reference/cli1.html#wp10290687

HTH,

Mark

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Correct Answer
Mark Yeates Thu, 12/18/2008 - 19:51

Hello Sarah,

The OK status when you issue the "show power" command indicates that the power supply/fan are operating normally and there are no alarms or faults detected.

The administrative field indicates the amount of power configured for that port which is a configurable option. Auto (which is the default) on a PoE port will automatically detect the amount of power needed to power the connected device. Here is a link showing how to configure power for PoE port.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/command/reference/cli1.html#wp10290687

HTH,

Mark

sarahr202 Fri, 12/19/2008 - 11:39

Thanks a lot Mark!

Let say we have to use Cisco method to detect poE device and allocate power.

1) Must Cdp be enabled in the above case?

2) How about we turn off cdp after the switch get all the information through cdp such as device type, power requirement ? Can we do that?

thanks a lot!

Correct Answer
Giuseppe Larosa Fri, 12/19/2008 - 13:12

Hello Sarah,

1) without CDP the switch can only detect there is a power over ethernet device on cable but canno adjust the power level and this can be a problem on high number of phones

2) CDP is also used to extend the QOS trust boundary to the ip phone and to instruct the phone on the vlan-id of the voice vlan and the CoS bits to use on sending voip frames this is needeed to provide end-to-end QoS.

CDP is also handy in troubleshooting to locate a phone and to see its model (defining a phone with the wrong model on CCM makes it unusable).

A standards based alternative to CDP named LLDP has been developed and can be used on newer IOS images to support third party ip phones.

For all the reasons stated above CDP or LLDP shoud be running all the time on the switch ports.

Hope to help

Giuseppe

sarahr202 Fri, 12/19/2008 - 18:25

Sorry to bother you .

I was looking at out put of "show power", when I noticed the following:

slot card-type pwr-requested pwr -allocated

1 ws-x6k-sup2 145.32 145.32

2 - - 145.32

I am concerned about the slot 2. How should i interpret this? I don't see any card on slot 2 but i see the pwr-requested= 145.32.

I understand from your last post the importance of cdp for smooth operation.

Just for example, if cdp was disabled, then switch ,having detected the poE device, would continue to supply default power as cdp being disabled, switch has no way of knowing the actual power required by the device?

Am I correct ?

thanks a lot!

Giuseppe Larosa Sat, 12/20/2008 - 03:59

hello Sarah,

please post the full show output an empty slot shoudn't be accounted for power consumption

Hope to help

Giuseppe

sarahr202 Sat, 12/20/2008 - 06:19

Sorry Giuseppe !

The output was from my book.

I will try to type the full output .

Thanks a lot!

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