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HP 2920 PoE+ issue. Need to delay POE delivery until after connected completely

 
NetworkingSteve
Occasional Visitor

HP 2920 PoE+ issue. Need to delay POE delivery until after connected completely

We recently purchased a large number of HP and Aruba rebranded 2920 PoE+ 24G and 48G switches.  We are having problems with POE being delivered to Aerohive access point Model 121's and Model 230's.  The problem appears to be that power is delivered before the switch is passing traffic, causing the Aerohives to never complete their connection.  This requires someone to either pull network manually, or using Hive Manager reboot all the AP's.   We did not notice this behavior on the 2620's that these switches have replaced with the exact same AP's.

Is there any graceful, permanent way to issue a power application delay for a specific time period, before powering POE ports, or to disable ports, PoE, or both, wait 10 seconds, and then reenable POE to the ports any time the switch is rebooted.  All this just to ensure that the switch is connected and ready before power hits the Aerohive APs.

Thanks for your time,

2 REPLIES
parnassus
Honored Contributor

Re: HP 2920 PoE+ issue. Need to delay POE delivery until after connected completely


NetworkingSteve wrote: The problem appears to be that power is delivered before the switch is passing traffic, causing the Aerohives to never complete their connection.

Pretty strange...physical port power status (generally) switches from PoE "Searching" status to PoE "Delivering" status (where "Searching" means that "The port is trying to detect a PD connection" and "Delivering" means that "The port is delivering power to a PD", here PD is the Powered Device), given that, how it is possible that PoE is provided to PD by the Switch before the Switch is fully booted and operational (so able to manage data traffic too as its very first task)?

Playing with the int <port-list> poe-allocate-by class option (instead of the poe-allocate-by usage, which is the default option) - and/or eventyally also using LLDP to allocate Power to PD via int <port-list> poe-lldp-detect enabled option to allow automatic power configuration if the link partner supports PoE - would check the signature of the PD before feeding the correct PoE power to the connected PD (poe-allocated-by class will use the power ramp-up signature of the connected PD to indentify which Power Class the device will be in).

What you are asking is a way to Power Cycle PoE Ports (something like doing a sequence of no interface n power and then a interface n power) since disabling and re-enabling PoE doesn't affect delivering Power to PD via that n port...but you shouldn't really forced to do that in normal operation/condition.

Which firmware version(s) are your HP ProCurve/Aruba 2920 Switches currently running?

 

TerjeAFK
Respected Contributor

Re: HP 2920 PoE+ issue. Need to delay POE delivery until after connected completely

If you have STP enabled on these switches have you set the ports where the access points are connected as edge ports? This will speed up the time it takes for the port to start forwarding traffic.