3560X Combined/Redundany Power Supplies

[Pierce Vasale]

I have 2 identical WS-3560X-24P-S running the same code (c3560e-ipbasek9-mz.122-55.SE5) with the same 2 power supplies (C3KX-PWR-715WAC).

However, a "show power inline" shows different results:

Switch 1: Available:720.0(w)  Used:277.2(w)  Remaining:442.8(w)

Switch 2: Available:1210.0(w)  Used:77.0(w)  Remaining:1133.0(w)

I cannot find anywhere how these could be running redundant vs combined power as I normally would in a chassis. Can anyone tell me WHY these show different available amounts? How it can be altered?

[Julio E. Moisa]

Hi Pierce,

If you are using IP hardphones or access points, that is the reason, you are consuming more power on the first switch than the second one. In few words you have more devices consuming more energy on the switch 1 

The show power inline shows the energy capacity used to provide energy to devices like: hardphones, cameras, access points, etc. 

show power inline

Use the show power inline user EXEC command to display the Power over Ethernet (PoE) status for the specified PoE port or for all PoE ports.

show power inline [[interface-id | consumption ] | module switch-number] [ | {begin | exclude | include} expression]

Syntax Description

interface-id	(Optional) Display PoE-related power management information for the specified interface.
consumption	(Optional) Display the power allocated to devices connected to PoE ports.
module switch-number	(Optional) Limit the display to ports on the specified stack member. The switch number is 1 to 9.
| begin	(Optional) Display begins with the line that matches the expression.
| exclude	(Optional) Display excludes lines that match the expression.
| include	(Optional) Display includes lines that match the specified expression.
expression	Expression in the output to use as a reference point.

Command Modes

User EXEC

Command History

Release	Modification
12.1(19)EA1	This command was introduced.
12.2(25)SEC	The consumption keywords were added.

Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.

Examples

This is an example of output from the show power inline command. In the display, port 2 is configured as static; power has been pre-allocated to this port, but no powered device is connected. Port 6 is a static port in the power-deny state because its maximum wattage is configured for 10 W. The connected powered device has a reported class maximum wattage for a Class 0 or Class 3 device. Table 2-31 describes the output fields.

Switch> show power inline

Module   Available     Used     Remaining

          (Watts)     (Watts)    (Watts) 

------   ---------   --------   ---------

1            370.0      114.9       255.1

2            370.0       34.3       335.

Interface Admin  Oper       Power   Device              Class Max

                            (Watts)                            

--------- ------ ---------- ------- ------------------- ----- ----

Fa1/0/1   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/2   static off        15.4    n/a                 n/a   15.4

Fa1/0/3   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/4   auto   on         6.3     IP Phone 7960       2     15.4

Fa1/0/5   static on         15.4    IP Phone 7960       2     15.4

Fa1/0/6   static power-deny 10.0    n/a                 n/a   10.0

Fa1/0/7   auto   on         6.3     IP Phone 7910       n/a   15.4

<output truncated>

This is an example of output from the show power inline command on a port:

Switch> show power inline fastethernet2/0/1 

Interface Admin  Oper       Power   Device              Class Max

                            (Watts)

--------- ------ ---------- ------- ------------------- ----- ----

Fa2/0/1   auto   on         6.3     IP Phone 7910       n/a   15.4

This is an example of output from the show power inline consumption command on all PoE switch ports:

Switch> show power inline consumption 

Default PD consumption : 15400 mW

This is an example of output from the show power inline module switch-number command on stack member 1:

Switch> show power inline module 1

Module   Available     Used     Remaining

          (Watts)     (Watts)    (Watts)

------   ---------   --------   ---------

1           370.0      166.2       203.9

Interface Admin  Oper       Power   Device              Class Max

                            (Watts)

--------- ------ ---------- ------- ------------------- ----- ----

Fa1/0/1   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/2   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/3   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/4   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/5   auto   on         6.3     IP Phone 7910       n/a   15.4

Fa1/0/6   auto   on         6.3     IP Phone 7910       n/a   15.4

<output truncated>

Table 2-31 show power inline interface Field Descriptions 

Field	Description
Admin	Administration mode: auto, off, static
Oper	Operating mode: •on—the powered device is detected, and power is applied. •off—no PoE is applied. •faulty—device detection or a powered device is in a faulty state. •power-deny—a powered device is detected, but no PoE is available, or the maximum wattage exceeds the detected powered-device maximum.
Power	The supplied PoE in watts
Device	The device type detected: n/a, unknown, Cisco powered-device, IEEE powered-device, <name from CDP>
Class	The IEEE classification: n/a, Class <0-4>
Available	The total amount of PoE in the system
Used	The amount of PoE allocated to ports
Remaining	The amount of PoE not allocated to ports in the system. (Available - Used = Remaining)

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_46_se/command/reference/cr/cli2.html#wp9457661

Please rate the comment if it is useful.

:-)

[Pierce Vasale]

Are you saying that if I put 9 more 3502i APs on Switch 2, that the total Available power would drop to 720W as well? Because that's not making any sense to me - it should only affect the Remaining Power Level.

[Julio E. Moisa]

Hi

I have attached an image from one of my switches, on some switches the maximum energy capacity per port is 30Watts and the devices usually consumes around 15Watts. 

Different switch models come with different capacity of power supply to provide energy, please check the following link:

http://www.cisco.com/c/en/us/products/switches/catalyst-3650-series-switches/models-comparison.html

[Pierce Vasale]

I understand that. But these are the EXACT same model switch with the EXACT same IOS and EXACT same power supplies. For that matter, they both only support Cisco 3502 APs.

I understand the drawing of different power, why there is more Used on one than the other. None of that explains why the one switch is offering 1210 Watts overall and the other will supposedly cutoff at 720 Watts.

[Pierce Vasale]

To clarify - The total AVAILABLE POWER is what is catching my attention here.

Available - Used = Remaining. I know why one has more in Use...but why does one have so much more Available to begin with?

[Reza Sharifi]

Most likely an IOS bug that is causing that.  Do you have good PSUs when you issue "sh environment all" on both switches?

HTH

[Pierce Vasale]

Yes. Both power supplies are good in both. Reseating doesn't do anything. These are production - so I've not power cycled them.

[Reza Sharifi]

I have seen a few bugs (some being cosmetic) when it comes to PSUs on the smaller switches. Most of the time the reboot will fix it temperately and after a while the issue comes back.  I think, you would need to upgrade to fix it permanently but before you do that, I suggest you open a ticket with TAC.  

Here is an example:

The reboot will make the other PSU go from "No Response" to "OK"  but after a few days it comes back again.  Both PSUs are working fine.

2A PWR-C1-1100WAC BHN1982V1JV OK Good Good 1100
2B PWR-C1-1100WAC CGN1902V1JF No Response Good Good 1100

HTH