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Beginner

Cisco 2960-X POE doesnt power more than 15 Power Devices

Hi Everybody,

hopefully someone will help to troubleshoot this problem. we are trying to connect more than 20 POE devices (PD)  called 0 Client. the operating system is Windows and managed via VDI. they are 802.1af compatible following the support of these PDs.

 

we cannot power via POE more than, sometimes 12 PDs, 13, 14 or 15 PDs maximum. Beyond that the PD doesnt power.

 

Even shut/no shut the port, changing the port, changing the cable with brand new ones.

 

We have tested with C2960X-48FPD-L and C2960X-24PD-L exactly with the same behaviour and the same number of powered PDs.

 

Even when the PDs are OS Shutdown and only asking for 1.2W, the result is the same:


#sh power inline module 1 detail | inc rawn|Interface
 Interface: Gi1/0/1
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/2
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.2
 Interface: Gi1/0/3
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/4
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/5
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/6
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/7
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/8
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/9
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/10
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.2
 Interface: Gi1/0/11
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/12
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/13
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.2
 Interface: Gi1/0/14
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.2
 Interface: Gi1/0/15
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.4
 Interface: Gi1/0/16
 Power drawn from the source: 15.4
 Maximum Power drawn by the device since powered on: 1.1
 Interface: Gi1/0/17
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/18
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/19
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/20
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/21
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/22
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/23
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0
 Interface: Gi1/0/24
 Power drawn from the source: 0.0
 Maximum Power drawn by the device since powered on: 0.0

 

this is the power available:

 

#sh power inline

Module   Available     Used     Remaining
          (Watts)     (Watts)    (Watts)
------   ---------   --------   ---------
1           370.0      215.6       154.4
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi1/0/1   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/2   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/3   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/4   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/5   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/6   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/7   auto   off        0.0     n/a                 n/a   30.0
Gi1/0/8   auto   off        0.0     n/a                 n/a   30.0
Gi1/0/9   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/10  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/11  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/12  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/13  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/14  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/15  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/16  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/17  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/18  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/19  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/20  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/21  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/22  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/23  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/24  auto   off        0.0     n/a                 n/a   30.0

 

 

This is an example of a ilpower debug, you can see a LLDP negociation which is working well for me:

 

(config)#int g1/0/21

(config-if)#sh

(config-if)#

Nov 12 10:45:57.595: ilpower delete power from pd linkdown Gi1/0/21

Nov 12 10:45:57.595: Ilpower interface (Gi1/0/21), delete allocated power 0

Nov 12 10:45:57.595:  ilpower_notify_lldp_power_via_mdi_tlv Gi1/0/21 pwr alloc 0

Nov 12 10:45:57.595: Gi1/0/21 AUTO PORT PWR Alloc 130 Request 130

Nov 12 10:45:57.595: Gi1/0/21: LLDP NOTIFY TLV:

    (curr/prev) PSE Allocation: 13000/0

    (curr/prev) PD Request    : 13000/0

    (curr/prev) PD Class      : Class 0/

    (curr/prev) PD Priority   : low/unknown

    (curr/prev) Power Type   : Type 2 PSE/Type 2 PSE

    (curr/prev) mdi_pwr_support: 7/0

    (curr/prev Power Pair)     : Signal/

    (curr/prev) PSE Pwr Source : Primary/Unknown

 

You can see here the PD is requesting 13W and the switch (PSE) is allocating the same. So the LLDP negotiation for me is working. Can you confirm my interpretation??

 

The big question is, why when increasing the number of PDs, even in a 2960X-24-PD-L or 2960X-48-FPD-L we cannot plug more than 15 PDs. Never beyond that!!

 

which kind of platform debugs we can follown in these situation?? does someone got this kind of problem?

 

Please note that we have manually allocated power from 7W increasing step by step until 23W, but the result is the same.

 

Please note also the customer tested on 11 Cisco 2960X (9 Cisco C2960X-48FPD and 2 C2960X-24PD-L) and the result is exactly the same, no more than 15 PDs (it varies from 12 and 15 PDs)

Everyone's tags (6)
4 REPLIES 4
Advocate

Re: Cisco 2960-X POE doesnt power more than 15 Power Devices

Hello @Mok_ASSAM,

 

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

 

In this link found this(I hope you find it useful) :

Maximum Power Allocation (Cutoff Power) on a PoE Port

When power policing is enabled, the switch determines one of the these values as the cutoff power on the PoE port in this order:

  1. Manually when you set the user-defined power level that the switch budgets for the port by using the power inline consumption default wattage global or interface configuration command

  2. Manually when you set the user-defined power level that limits the power allowed on the port by using the power inline auto max max-wattage or the power inline static maxmax-wattage interface configuration command

  3. Automatically when the switch sets the power usage of the device by using CDP power negotiation or by the IEEE classification and LLDP power negotiation.

Use the first or second method in the previous list to manually configure the cutoff-power value by entering the power inline consumption default wattage or the power inline [auto |static max] max-wattage command.

 

If you do not manually configure the cutoff-power value, the switch automatically determines it by using CDP power negotiation or the device IEEE classification and LLDP power negotiation. If CDP or LLDP are not enabled, the default value of 30 W is applied. However without CDP or LLDP, the switch does not allow devices to consume more than 15.4 W of power because values from 15400 to 30000 mW are only allocated based on CDP or LLDP requests. If a powered device consumes more than 15.4 W without CDP or LLDP negotiation, the device might be in violation of the maximum current (Imax) limitation and might experience an Icut fault for drawing more current than the maximum. The port remains in the fault state for a time before attempting to power on again. If the port continuously draws more than 15.4 W, the cycle repeats.

 

Regards

Beginner

Re: Cisco 2960-X POE doesnt power more than 15 Power Devices

Hello,

 

@luis_cordova

thanks for your answer, i really need this quality of answer to figure out or workaround.

 

you talked about cutoff, but the PDs are consuming only 1.2W. I cannot imagine a Cutoff (unless there is a bug) with 1.2W.

 

 

Advocate

Re: Cisco 2960-X POE doesnt power more than 15 Power Devices

Hello @Mok_ASSAM,

 

The link mentioned that if CDP or LLDP it was not enabled, the default value of 30 W was applied, regardless of the power that the PD consumed.

If those protocols are OK, effectively, it could be a bug.

 

Regards

Beginner

Re: Cisco 2960-X POE doesnt power more than 15 Power Devices

Hello,

 

may be someone from Cisco can help.

 

of course there is already a ticket reported to the TAC.

 

from my side i cannot confirm if it is a bug or not.

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