Newly added PoE ports are going down after connecting more than 4 PoE+ devices in a EX2300-C with Link Layer Discovery Protocol (LLDP) power negotiation enabled.
This article provides an explanation and lists the Junos OS releases in which the issue is resolved.
This scenario has a default configuration on the switch; PoE power management is set to class; and lldp/lldp-med is enabled on all interfaces.
The user has connected 6 PoE+ devices to EX2300-C. There is plenty of power budget but the interface ge-0/0/9 and ge-0/0/10, which are connected to the PoE+ devices, are down. The error that is reported on the port is shown below:
user@router > show poe interface Interface Admin Oper Pair/Mode Max Priority Power Class status status status power consumption ge-0/0/0 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/1 Enabled ON 2P/AT 25.5W(L) Low 8.4W 4 ge-0/0/2 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/3 Enabled ON 2P/AT 25.5W(L) Low 8.2W 4 ge-0/0/4 Disabled Disabled 2P/AT 0.0W Low 0.0W not-applicable ge-0/0/5 Enabled ON 2P/AT 25.5W(L) Low 8.4W 4 ge-0/0/6 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/7 Enabled ON 2P/AT 25.5W(L) Low 8.6W 4 ge-0/0/8 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/9 Enabled OFF 2P/AT 30.0W Low 0.0W not-applicable <-- This interface is OFF ge-0/0/10 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable <-- This interface is OFF ge-0/0/11 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable
{master:0} user@router > show poe interface ge-0/0/9 PoE interface status: PoE interface : ge-0/0/9 Administrative status : Enabled Operational status : OFF Operational status detail : Static Mode Exceeded Power Limit <-- Error FourPair status : Disabled Power limit on the interface : 30.0W Priority : Low Power consumed : 0.0W Class of power device : not-applicable PoE Mode : 802.3at {master:0} user@router > show poe interface ge-0/0/10 PoE interface status: PoE interface : ge-0/0/10 Administrative status : Enabled Operational status : OFF Operational status detail : Static Mode Exceeded Power Limit <-- Error FourPair status : Disabled Power limit on the interface : 15.4W Priority : Low Power consumed : 0.0W Class of power device : not-applicable PoE Mode : 802.3at user@router > show poe controller Controller Maximum Power Guard Management Status Lldp index power consumption band Priority 0 146W 33.80W 0W Class AT_MODE Disabled {master:0} user@router > show chassis power-budget-statistics fpc 0: ------------------------------------------------------------------------- PSU 0 (JPSU-170W-AC ) : 170 W Online Power redundancy configuration : N+0 Total power supplied by all online PSUs : 170 W Base power reserved : 24 W Total power allocated for PoE : 146 W Total PoE power consumed : 33 W Total PoE power remaining : 113 W
Rebooting the switch does not resolve the issue. The port would turn on briefly after the switch reboot, but it goes down again.
On the EX2300-C-12P platform, the PoE ports are going down after the total PoE consumed power exceeds 124W but not reaching the maximum power of 146W. This is because the maximum PoE power for the EX2300-C-12P platform is 124W, not 146W. Refer to Power over Ethernet (PoE) Ports for an explanation.
This issue is resolved in the following Junos OS releases:
Junos:18.1R3-S10
Junos:18.2R3-S3
Junos:18.3R3-S2
Junos:19.2R2
Junos:19.3R3
Junos:19.4R2
Junos:20.1R2
Junos:20.2R1
As per the maximum PoE power value, this behavior is expected. The PoE max value in the output of show poe controller and show chassis power-budget-statistics will be updated to 124W instead of 146W in the fixed Junos OS versions.
show poe controller
show chassis power-budget-statistics
Workaround:
Disable the power-negotiation for lldp using the below command:
set protocol lldp interface all power-negotiation disable
When LLDP power negotiation is disabled:
user@router > show poe interface Interface Admin Oper Pair/Mode Max Priority Power Class status status status power consumption ge-0/0/0 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/1 Enabled ON 2P/AT 30.0W Low 7.8W 4 ge-0/0/2 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/3 Enabled ON 2P/AT 30.0W Low 5.8W 4 ge-0/0/4 Disabled Disabled 2P/AT 0.0W Low 0.0W not-applicable ge-0/0/5 Enabled ON 2P/AT 30.0W Low 5.6W 4 ge-0/0/6 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/7 Enabled ON 2P/AT 30.0W Low 5.6W 4 ge-0/0/8 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable ge-0/0/9 Enabled ON 2P/AT 25.5W(L) Low 4.6W 4 <-- This interface is UP ge-0/0/10 Enabled ON 2P/AT 15.4W Low 2.2W 3 <-- This interface is UP ge-0/0/11 Enabled OFF 2P/AT 15.4W Low 0.0W not-applicable
2020-09-02: Minor, non-technical edit