POE Works from Cisco Injector but not from Cisco Switch

[Brian Maxwell]

Hello,

I have an IP camera that was working just fine until recently.  Now the camera will power up if I use a Cisco Small Business POE injector where the permanent switch is but will not power up if connected to the switch.

We have verified that POE is enabled and functionig on the port by plugging another device into the switch.

Is there some negotion that an enterprise switch performs before providing power that an injector wouldn't do?

We've seen similar issues in the past but doing a shut / no shut on the port brings the POE back online.  I can get model numbers if needed but it's not my gear and I forgot to write it down when I was in the IDF.

My fear is that I'm going to RMA the camera, they'll power it up using an injector or cheap switch and it'll work just fine like it does with my injector.

Thanks for any info.

[glen.grant]

  You really need to know the switch models.  It's possible  that the switch that you are plugging into cannot give adequate power for the device and only an injector will work.  POE is normally on by default and is only shutoff if you used power inline never on the interface.   By using the show power commmands you can also determine if the switch is supplying max power for the system . Check system logs for anything pertaing to the port the camera is plugged into.

[Leo Laohoo]

I have an IP camera that was working just fine until recently.  Now the camera will power up if I use a Cisco Small Business POE injector where the permanent switch is but will not power up if connected to the switch.
We have verified that POE is enabled and functionig on the port by plugging another device into the switch.

If you've got a Catalyst switch, please state the model.

As what Glen has stated, some switches will only provide pre-standard PoE and maybe your IP Camera requires higher power. 

One of the reasons why I'm asking the model is because I want to determine if your switch can support TDR.  I have a feeling you have a cable problem.

[devils_advocate]

We use IP Cameras onboard vessels at work and there are some which use more than the default 15.4w of Power.

Some use nearly 30w so we use switches which are PoE+ (thus supplying more than 15.4w per port) and those which can have more than one power supply so we can increase the total power for PoE per switch.

[Brian Maxwell]

I'll hopefully get the model tomorrow.  They're new (2012) catalyst switches though not provided by or supported by me.  I won't be on site today due to snow and all roads pretty much closed.  Are there versions of the catalyst switches that provide non-standard POE?

I didn notice that the stated output on the POE injector indicates that it can provide slightly more than 17.5W so it seems to be non-standard.

Camera manual states that the cameras are class 3 devices.  7.5W nominal with heater on.

Regarding possible cabling issue, cable tests out end to end fine with a linkrunner.  The only thing that hasn't been tested is the jumper between the last biscuit jack and the camrea.

All Cabling is Cat6 and was certified at installation.

[Leo Laohoo]

All Cabling is Cat6 and was certified at installation.

Sorry, but I get hysterical everytime I see this statement.  However, our "expert" cable installers no longer find it funny (with their shonky cable work) since we've started testing their work with our 2960S using the in-built TDR.

Are there versions of the catalyst switches that provide non-standard POE?

You won't find any new switches that will only provide up to 7.5w PoE.  All enterprise-grade PoE should be able to provide, a minimum of, 15.4w PoE.

[Brian Maxwell]

Sorry for the lack of response.  Crazy week.  The switches are WS-x4748-rj45V-+E

We installed the new camera and it came right online as expected.  Just curious how this randomly happens.

[Leo Laohoo]

I'd be doing the TDR.