Perpetual/Fast PoE

[adamgibs7]

Dears

just need to clarify some doubts , the access ports for ip phone remains up while still the switch boots but what abt the trunk link ports that has to transfer the data packets to the default gateway, does those also comes up faster and negotiate with the uplink switches??? actually need to know how the feature works appropriately in perpetual or fast poe mode.

[Leo Laohoo]

Without Perpetual PoE or Fast PoE, the powered device (PD) only starts to boot up after the switch has booted.  A switch, typically, boots up in 5 minutes and, depending on the model of the phone, takes another 3 to 4 minutes for a phone to join, gets an IP address and contacts the call manager.  All up, 10 minutes is "lost". 

With Perpetual PoE or Fast PoE enabled, the phone starts to receive power when the switch starts booting into ROMMON.  The boot-up time for a phone now drops to around 5 minutes.

It is not just "enable THIS" and and system works.  After enabled Fast PoE or Perpetual PoE on the port(s), the switch needs to be rebooted (cold reboot or "reload" command) because the switch needs to "know" that then PD requirement per port.  Once this is done then Perpetual PoE/Fast PoE will start to work.  

Hope this helps.

[adamgibs7]

Dear Leo

thanks for the good explanation, all that you replied it really matters, so along with this we should also see how fast the trunk ports are coming even becz they are the ones to send the traffic towards call manager, 

Please correct me if i m wrong, how to make these trunk ports to come fast becz i have these switches in stack and they are in port-channel to uplink C9500 switches which are in virtual stack.

[Leo Laohoo · Accepted solution]

Trunk ports usually goes up about 30s to 60 seconds after the switch finishes booting.

[adamgibs7]

thanks leo for your replies.