PoE/PoE+ allocation using LLDP information

​Syntax:

​Example:

You can enter this command to enable LLDP​ detection:

HP Switch(config) # int A7 poe-lldp-detect enabled

or in interface context:

HP Switch(eth-A7) # poe-lldp-detect enabled

For more information on PoE/PoE+ and LLDP, see PoE/PoE+ allocation using LLDP information.

Use this command and insert the desired port or ports:

For more information on LLDP, see PoE/PoE+ allocation using LLDP information.

The DLC​​ for PoE provides more exact control over the power requirement between a PSE and PD. The DLC works in conjunction with the PLC and is mandatory for any Type-2 PD that requires more than 12.95 watts of input power.

	NOTE: DLC is defined as part of the IEEE 802.3at standard.

You can implement the power negotiation between a PSE and a PD at the physical layer or at the data link layer. After the link is powered at the physical layer, the PSE can use LLDP to query the PD repeatedly to discover the power needs of the PD. Communication over the data link layer allows finer control of power allotment, which makes it possible for the PSE to supply dynamically the power levels needed by the PD. Using LLDP is optional for the PSE but mandatory for a Type 2 PD that requires more than 12.95 watts of power.

If the power needed by the PD is not available, that port is shut off.

There are two ways LLDP can negotiate power with a PD:

Enabling PoE-lldp-detect allows the data link layer to be used for power negotiation. When a PD requests power on a PoE port, LLDP interacts with PoE to see if there is enough power to fulfill the request. Power is set at the level requested. If the PD goes into power-saving mode, the power supplied is reduced; if the need for power increases, the amount supplied is increased. PoE and LLDP interact to meet the current power demands.

​Syntax:

​Example:

You can enter this command to enable LLDP​ detection:

or in interface context:

	NOTE: Detecting PoE information via LLDP affects only power delivery; it does not affect normal Ethernet connectivity.

You can view the settings by entering the show power-over-ethernet brief command, as shown in Port with LLDP configuration information obtained from the device.

HP Switch (config)# show power-over-ethernet brief

 Status and Counters - Port Power Status


  POE   | Power   Power     Alloc Alloc  Actual Configured  Detection   Power
  Port  | Enable  Priority  By    Power  Power  Type        Status      Class
  ----- + ------- --------- ----- ------ ------ ----------- ----------- ----
  A1    | Yes     low       usage 17 W   0.0 W  Phone1      Delivering  1
  A2    | Yes     low       usage 17 W   0.0 W              Searching   0
  A3    | Yes     low       usage 17 W   0.0 W              Searching   0
  A4    | Yes     low       usage 17 W   0.0 W              Searching   0
  A5    | Yes     low       usage 17 W   0.0 W              Searching   0
  A6    | Yes     low       usage 17 W   8.4 W              Delivering  0
  

​Syntax:

	NOTE: If LLDP is disabled at runtime, and a PD is using PoE+ power that has been negotiated through LLDP, there is a temporary power drop; the port begins using PoE+ power through the PLC. This event is recorded in the Event Log. An Example: message would look like the following: ​ ​ W 08/04/13 13:35:50 02768 ports: Port A1 PoE power dropped. Exceeded physical classification for a PoE Type1 device (LLDP process disabled) When LLDP is enabled again, it causes a temporary power drop. This event is also recorded in the Event Log. An Example: message looks like the following: ​ ​ W 08/04/13 13:36:31 02771 ports: Port A1 PoE power dropped. Exceeded physical classification due to change in classification type (LLDP process enabled)

​Syntax:

HP Switch(config)# show lldp config 4

 LLCP Port Configuration Detail

  Port : 4
  AdminStatus [Tx_Rx] : Tx_Rx
  NotificationsEnabled [False] : False
  Med Topology Trap Enabled [False] : False


  TLVS Advertised:
   * port_descr
   * system_name
   * system_descr
   * system_cap

   * capabilities
   * network_policy
   * location_id
   * poe

   * macphy_config
   * poeplus_config

  IpAddress Advertised:

Local power information shows an Example: of the local device power information using the show lldp info local-device <port-list> command.

HP Switch(config)# show lldp info local-device A1

 LLCP Local Port Information Detail

  Port     : A1
  PortType : local
  PortId   : 1
  PortDesc : A1
  Pvid     : 1

 Poe Plus Information Detail

     Poe Device Type           : Type2 PSE
     Power Source              : Primary
     Power Priority            : low
     PD Requested Power Value  : 20 Watts
     PSE Actual Power Value    : 20 Watts

Remote power information shows the remote device power information using the show lldp info remote-device <port-list> command.

HP Switch(config)# show lldp info remote-device A3

 LLCP Remote Device Information Detail

  Local Port   : A3
  ChassisType  : mac-address
  ChassisId    : 00 16 35 ff 2d 40
  PortType     : local
  PortId       : 23
  SysName      : HPSwitch
  System Descr : HP Switch, revision YA.14.xx
  PortDescr    : 23
  Pvid         : 55

  System Capabilities Supported  : bridge, router
  System Capabilities Enabled    : bridge

  Remote Management Address
     Type    : ipv4
     Address : 10.0.102.198

  Poe Plus Information Detail

     Poe Device Type           : Type2 PD
     Power Source              : Only PSE
     Power Priority            : low
     PD Requested Power Value  : 20 Watts
     PSE Actual Power Value    : 20 Watts

The advertisement of power with TLVs for LLDP PoE+ is enabled by default. If LLDP is disabled at runtime and a PD is using PoE+ power that has been negotiated through LLDP, there will be a temporary power drop. The port will begin using PoE+ power through the PLC. This event is recorded in the event log. An Example: message would look like the following:

W 08/04/13 13:35:50 02768 ports: Port A1 PoE power dropped.
Exceeded physical classification for a PoE Type1 device
(LLDP process disabled)

When LLDP is enabled again, it causes a temporary power drop. This event is also recorded in the event log. An Example: message looks like the following:

W 08/04/13 13:36:31 02771 ports: Port A1 PoE power dropped.
Exceeded physical classification due to change in
classification type (LLDP process enabled)