3560-48PS POE Budget

[esprit1987]

Hi,

Hope you can help.

I'm running 3560-48 and 24 PS-L's (640W PSUs) with non Cisco POE edge devices. The issue I'm having is these devices won't draw much more than 3-6 Watts but the switch wants to use 15.4W per port, depleting my POE budget! I have tried setting "power inline auto max" but the port shuts down.

I have seen you can use the "power inline consuption" command, but its not a recognised command as I'm only running an L not an E image.

Is there anything else I can do other adding a 2nd PSU to these switches to increase my global POE budget? I have attached my POE environment, please note I need to use at least 38 ports hence my conumdrum.

I look forward to your feedback.

[Mark Malone]

Hi

if ports shutting down something else is wrong ,it shiuldnt do that

i just tested it to check on a 3650 as below results , 30w port running 7821

Gi1/0/40 auto on 3.2 IP Phone 7821 1 30.0

Set the port to 4000kw lowest i can go back from 30000kw

Gi1/0/40 auto on 4.0 IP Phone 7821 1 4.0

sh int g1/0/40
GigabitEthernet1/0/40 is up, line protocol is up (connected)

interface GigabitEthernet1/0/40
switchport access vlan x
switchport mode access
switchport voice vlan x
ip access-group PERMIT-ANY in
power inline auto max 4000 --------------------------Here
authentication control-direction in
authentication event fail action next-method
authentication event server dead action reinitialize vlan x
authentication event server dead action authorize voice
authentication event server alive action reinitialize
authentication host-mode multi-auth
authentication open
authentication order mab dot1x
authentication priority dot1x mab
authentication port-control auto
authentication periodic
authentication timer reauthenticate server
authentication timer inactivity server dynamic
authentication violation restrict
mab
dot1x pae authenticator
dot1x timeout tx-period 10
auto qos trust dscp
spanning-tree portfast
spanning-tree bpduguard enable
service-policy input AutoQos-4.0-Trust-Dscp-Input-Policy
service-policy output AutoQos-4.0-Output-Policy
ip dhcp snooping limit rate 7
end

what version are you running on the switch ?  are you giving it enough power to stay up , try increasing it ....

[esprit1987]

Many thanks for the prompt response.
I have tried “power inline auto max” with a number of different wattages and the POE on the port shuts down every time with “inline power denied.reason:insufficient power”. But I can see the devices are drawing no more the 3.2 watts?
Essentially the below from Cisco’s troubleshooting guide summarises my issue…

“For example, unidentified devices might need only 6 W, but they are allocated maximum PoE power (up to 15.4 W), and the power budget can be depleted before all available ports on the switch have been provided power. This results in a symptom where a known-good powered device is connected to a known-good PoE port on a switch, but the powered device does not power on. “

And the below implies that I cannot manually adjust the port to free up my POE budget as I am running 3650-L not E

“Some of the newer switches, such as the Catalyst 3750-E and 3560-E can adjust the power budget according to actual measured power usage. “

*******My software version is 16.6********

I’m clearly missing something ☹

[Leo Laohoo]

When a powered device is connected to a Cisco switch, the Cisco switch ALWAYS pushes 15.4w. It doesn't matter if the powered device requires <15.4w or >15.4w. 15.4w is ALWAYS pushed to the downstream client. The objective is to provide power to the client to boot up. If the client talks CDP or LLDP, then it can "negotiate" with the switch to ramp up (or down) the power.
The output is showing the powered devices are doing the first part right (switch pushing 15.4w), HOWEVER, the powered devices are not "negotiating" the power with the switch.
So my question will be this: Do the powered device support CDP or LLDP?
If they do, fine. Enable CDP or LLDP and see if it improve things.
If they don't (mostly they don't), then manually configure the power draw to each port.

[esprit1987]

Further to my previous reply...
I strongly suspect that CDP/LLDP are not supported but I have asked the question...