I recently came across this post which proved very interesting when Polycom phones use Cisco LLDP-MED to configure a dedicated Voice VLAN and the switch is also providing PoE.The issues arrised due to incompatability between the power states a phone goes through and the Cisco being a little too clever. The phone moves up the power states too quickly and the Cisco kills the port because it thinks there is a power spike and hence the phone reboots.The only quick option is to turn off LLDP-MED globally on the Cisco kit and go back to using the DHCP Option method of assigning a Voice VLAN (see this article).However on doing a little more digging you could always turn off LLDP-MED for power management on a port by port basis using the following:interface interface-id
no lldp med-tlv-select power-management