Issue with PoE neg after upgrading Catalyst 2960XR

[Energia]

After upgrading a few 2960XR to the latest IOS (15.2.7E9) we have seen something that looks like a PoE negotiation issue with some G4S/Amag security nodes.

After the upgrade it seems that the switch and the endpoint is not able to negotiate enough PoE. The switch are able to provide power, but 15.4 W instead of 30 W.

The Amag/G4S device do have a jump switch for PoE (Hi/LO) that define how much it should request, we have seen the issue when the endpoint is set to «HI» and the switch are running the latest IOS.

Without beeing able to document it in any way, it seems that they try to nogotiate 30 W, but that the switch declines the request of 30 W (after some evaluation it concludes that it is not able to provide 30 W)and then provides 15,4 W.
I have been looking in to the documentation regarding PoE, but have not been able to find anything that supports this theory.

Have anyone had a similar issue?

Are the switch able to do some evaluation of the physical cabling, and decline the request if it finds that it is no sutable (i.e. the resistance is to high)

I guess that this would be possible, since the 2900-series do have the TDR-feature (test-cable tdr)

Downgrading solves the issue.

[balaji.bandi]

i do not remember correctly upgrade may causing that version you mentioned. (this may be bug)

Try setting up the port and see if that fix the issue as per below document :

Maximum Power Allocation (Cutoff Power) on a PoE Port

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-0_2_EX/int_hw_components/configuration_guide/b_int_152ex_2960-x_cg/b_int_152ex_2960-x_cg_chapter_0111.html

[Leo Laohoo]

If the switch goes back to the original version, does the Amag work?

[Energia]

If we downgrade to 15.2(6)E3 everything works fine.