I have replaced my old SG300-10P with a new CBS350-8P-E-2G but having some problem with PoE and a IP phone. When I reboot the switch it works for few hours and then the phone is off, i.e. has no power. I have only two PoE devices connected, an access point and this ip phone. The access point works fine all the time. From the specs both devices are far from exceeding the possible poe limits of the switch. Both worked fine on the old switch.
While it's working, it all looks good:
sw2(config)#do show power inline
Power-limit mode: Port based
Usage threshold: 95%
Trap: Disable
Legacy Mode: Enable
Inrush Test: Enable
Guard-Band Value: Static (2W)
Unit Module Nominal Consumed Temp SW PSE chipset
Power (W) Power (W) (C) Version HW Revision
---- -------------- --------- ------------ -------- ------------- -----------------
1 CBS350-8P-E-2G 60 17 (28%) 52 0.2.0.17 TPS2388 - 0x40C4
Interface Admin Oper Power (W) Class Device Priority
---------- ---------- ----------- ----------------- ----- -------------- --------
gi1 Auto On 6.839 (15.4) 4 low
gi2 Never Searching 0.0 - low
gi3 Never Searching 0.0 - low
gi4 Never Searching 0.0 - low
gi5 Never Searching 0.0 - low
gi6 Never Searching 0.0 - low
gi7 Auto On 2.35 0 low
gi8 Never Searching 0.0 - low
sw2(config)#do show power inline ge7
Interface Admin Oper Power (W) Class Device Priority
---------- ---------- ----------- ----------------- ----- -------------- --------
gi7 Auto On 2.35 0 low
Port Status: Port is on. Valid resistor detected
Port standard: 802.3AT
Admin power limit: 30.0 watts
Time range:
Link partner standard: 802.3AT
Max Power Allocation: 30.0 watts
Spare pair: Disabled
Negotiated power: 0.0 watts (None)
Current (mA): 44
Voltage(V): 53.0
Overload Counter: 32
Short Counter: 0
Denied Counter: 415164
Absent Counter: 15
Invalid Signature Counter: 0 However, a few hours later the port goes down:
20-Jan-2022 00:26:36 :%LINK-W-Down: gi7
19-Jan-2022 20:27:50 :%STP-W-PORTSTATUS: gi7: STP status Forwarding
19-Jan-2022 20:27:45 :%LINK-I-Up: gi7
And the state is at fault:
sw2#show power inline
Power-limit mode: Port based
Usage threshold: 95%
Trap: Disable
Legacy Mode: Enable
Inrush Test: Enable
Guard-Band Value: Static (2W)
Unit Module Nominal Consumed Temp SW PSE chipset
Power (W) Power (W) (C) Version HW Revision
---- -------------- --------- ------------ -------- ------------- -----------------
1 CBS350-8P-E-2G 60 15 (25%) 52 0.2.0.17 TPS2388 - 0x40C4
Interface Admin Oper Power (W) Class Device Priority
---------- ---------- ----------- ----------------- ----- -------------- --------
gi1 Auto On 6.84 (15.4) 4 low
gi2 Never Fault 0.0 - low
gi3 Never Fault 0.0 - low
gi4 Never Fault 0.0 - low
gi5 Never Fault 0.0 - low
gi6 Never Fault 0.0 - low
gi7 Auto Fault 0.0 - low
gi8 Never Fault 0.0 - low
sw2#show power inline gi7
Interface Admin Oper Power (W) Class Device Priority
---------- ---------- ----------- ----------------- ----- -------------- --------
gi7 Auto Fault 0.0 - low
Port Status: Port is off. Power budget exceeded
Port standard: 802.3AT
Admin power limit: 30.0 watts
Time range:
Max Power Allocation: 30.0 watts
Spare pair: Disabled
Negotiated power: 0.0 watts (None)
Current (mA): 0
Voltage(V): 0.0
Overload Counter: 36
Short Counter: 0
Denied Counter: 444802
Absent Counter: 17
Invalid Signature Counter: 0 Even the other ports which don't use PoE and where I have disabled PoE are at fault and report overload state
Port Status: Port is off. Overload state
According to the specs the IP phone is 802.3af class 0 with a max of 3.5W.
I wouldn't know how to exceed the power budget or overload the system with these two devices and all other ports with poe disabled. The SG300 didn't have a problem with those two devices.
Initially, I had class based power-limit and I have switched to port based for tests, but no change.
I also don't see how to reset the fault state on a port to get it working again, excepting for switching the power-limit mode which resets all poe ports or rebooting...
