1-11To do… Use the command… RemarksEnter system view system-view —EnterEthernetinterface viewinterface interface-typeinterface-numberEnter Ethernetinterface viewor port groupview Enter portgroup viewport-group manualport-group-nameRequiredUse either command.Set the encapsulation formatfor LLDPDUs to SNAP lldp encapsulation snapRequiredEthernet II encapsulationformat applies by default.To restore the default, usethe undo lldpencapsulation command.Both the LLDPDU transmit interval and delay must be less than the TTL to ensure that the LLDPneighbors can receive LLDP frames to update information about the device you are configuring beforeit is aged out.Configuring CDP CompatibilityFor detailed information about voice VLAN, refer to VLAN Configuration in the Access Volume.You need to enable CDP compatibility for your device to work with Cisco IP phones.As your LLDP-enabled device cannot recognize CDP packets, it does not respond to the requests ofCisco IP phones for the voice VLAN ID configured on the device. This can cause a requesting Cisco IPphone to send voice traffic without any tag to your device, disabling your device to differentiate the voicetraffic from other types of traffic.By configuring CDP compatibility, you can enable LLDP on your device to receive and recognize CDPpackets from Cisco IP phones and respond with CDP packets carrying the voice VLAN configurationTLV for the IP phones to configure the voice VLAN automatically. Thus, the voice traffic is confined inthe configured voice VLAN to be differentiated from other types of traffic.Configuration PrerequisitesBefore configuring CDP compatibility, make sure that:z LLDP is enabled globally.z LLDP is enabled on the port connected to an IP phone and is configured to operate in TxRx modeon the port.
