Symptom:
Steps:
1. Both CDP and LLDP enabled on 3560x switch
2. Configure voice vlan on switchport
interface GigabitEthernet0/2
 switchport access vlan 77
 switchport mode access
 switchport voice vlan 985
 spanning-tree portfast
3. PoE power up phone
4. Check power consumption on switch
Result:
It is 15.4w initially then after phone get stable, it is 12.9w
Switch3560x#show power inline g0/2
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi0/2     auto   on         15.4    IP Phone 8861       4     30.0

Interface  AdminPowerMax   AdminConsumption
             (Watts)           (Watts)
---------- --------------- --------------------

Gi0/2                 30.0                 30.0
Switch3560x#show power inline g0/2
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi0/2     auto   on         12.9    IP Phone 8861       4     30.0

Interface  AdminPowerMax   AdminConsumption
             (Watts)           (Watts)
---------- --------------- --------------------

Gi0/2                 30.0                 30.0

5. Remove the voice vlan config on switchport
 switchport access vlan 985
 switchport mode access
 spanning-tree portfast
6. Powercycle phone
7. Check power consumption on switch
Result:
It is always 14.2w
Switch3560x#show power inline g0/2
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi0/2     auto   on         14.2    IP Phone 8861       4     30.0

Interface  AdminPowerMax   AdminConsumption
             (Watts)           (Watts)
---------- --------------- --------------------

Gi0/2                 30.0                 30.0

Conditions:
See steps in symptoms