Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

Figure 1. Power via MDI TLV packet format

Image RemovedImage Added

The fields of Power via MDI TLV are described as follows:

...

Field                       

Functions

Description

0

Port type

1: PSE-side port

0: PD-side port

1

Whether the PSE supports MDI power supply.

1: indicates that the PSE supports MDI power supply.

0: indicates that the PSE does not support MDI power supply.

2

MDI power supply status of the PSE.

1: enabled

0: disabled

3

Whether the PSE can control the line pair.

1: indicates that the PSE can control the line pair.

0: indicates that the PSE cannot control the line pair.

4-7

Reserved.

-

...


  • PSE power Pair: The PSE power pair field contains an integer value as defined by the pethPsePortPowerPairs object in IETF RFC 3621.

...

Field

Functions

Description

Priority

Power supply priority of an interface.

11: indicates the lowest priority.

10: indicates the secondary highest priority.

01: indicates the highest priority.

NOTE:

This field contains four bits. The two left-most bits are reserved for the system.

Source

 

 

 

 





Power supply source.

PD:

  • 11: indicates the PSE and local source.
  • 10: indicates the local.
  • 01: indicates the PSE.

PSE:

  • 11: indicates to be reserved.
  • 10: indicates the backup power supply.
  • 01: indicates the primary power supply.

Type

 

 

 

 





Power supply type.

01: indicates the PD that supports IEEE 802.3at.

00: indicates the PSE that supports IEEE 802.3at.

11: reserved.

10: reserved.

...

Field

Functions

Value/Meaning

PSE allocated

PSE allocated power value

  • Power=0.1*(decimal value of bits) Watts. The value is an integer that ranges from 1 to 255. For example, if the value of the field is 255, the exchange power is 25.5 W.
  • When the PoE power is sufficient, the values of PD Requested Power value and PSE allocated Power value are the same.

 PoE over LLDP Power Negotiation Mechanism

If PoE over LLDP power negotiation function is enabled on PSE, the PSE and the PD will periodically send LLDP packets to each other to perform LLDP power negotiation once the PD device is detected by the PSE. PoE over LLDP power negotiation starts when PSE receives LLDP packets from PD.

...