Ruijie RG-S2900G-E Series - Page 102

Configuration Guide Configuring PoE Configuration
Setting the Descriptor of the PD on a Port
In practical applications, you may often need to record the name of a PD connected to a certain PoE port. RFC 3621
defines a configuration item named pethPsePortType to set the descriptor of the PD on a port.
CLI commands are also available on Ruijie switches to set the descriptor of the PD on a port.
Command
Function
Ruijie# configure
Enters the global configuration mode
Ruijie(config)# interface fastEthernet interface-id
Enters the interface configuration mode and specifies the
physical port to be configured
Ruijie(config-if)#poe pd-description pd-name
Sets the descriptor of the PD on the port, which is a string
of at most 32 characters just the same as that in the MIB
Ruijie(config)# end
Returns to the global configuration mode
Ruijie#write
Saves the settings to ensure that the settings take effect
upon the next startup
For example, you can run the following commands in turn to set the descriptor of the PD on the FE port 0/1:
Ruijie# configure
Ruijie(config)# interface FastEthernet 0/1
Ruijie(config-if)# poe pd-description ap220
Ruijie(config-if)# end
 The CLI is also set if you set the descriptor of the PD on a port by specifying the value of pethPsePortType in the MIB.
Setting the Link Layer Discovery Protocol (LLDP) Classification Function
According to IEEE 802.3at, PDs supporting 802.3at must be able to support both 2-Event Physical Layer classification
and LLDP classification (which is known as Data Link Layer classification in protocols). PDs must be able to exchange
LLDP packets with the PSE switch to indicate that they are Class 4 devices. The PSE power supply equipment needs only
to support either of the two classification methods. Ruijie switches support LLDP classification.
After Class 4 Type 2 PDs are installed in a PoE switch, the PoE switch performs detection and classification first before
supplying power to the PDs. By default, the PoE switch identifies a PD as a Type 1 device and allocates a maximum of 13
W to each PD. If a PD is identified as a Type 2 device after LLDP classification and the PoE switch provides a sufficient
power, the PD can obtain a maximum of 25.5 W power. If the PoE switch does not have a sufficient power for the PD, the
PD will keep sending LLDP power request packets to request power.
The following table lists the maximum power available for each class and type of PDs:
Class
Type
Maximum Power (W)
Power Allocated by
Power Management (W)
Class 0
Type 1
13
15.4
Class 1
Type 1
3.9
4
Class 2
Type 1
6.5
7
Class 3
Type 1
13
15.4
Class 4
Type 1
13
15.4
Class 4
Type 2
25.5
30