165Configuration prerequisitesBefore you configure CDP compatibility, complete the following tasks:• Globally enable LLDP.• Enable LLDP on the port connecting to an IP phone and configure the port to operate in TxRx mode.Configuring CDP compatibilityCDP-compatible LLDP operates in one of the follows modes:• TxRx: The CDP packets can be transmitted and received.• Disable: The CDP packets can neither be transmitted nor be received.To make CDP-compatible LLDP take effect on certain ports, first enable CDP-compatible LLDP globally,and then configure CDP-compatible LLDP to operate in TxRx mode.Follow these steps to enable LLDP to be compatible with CDP:To do… Use the command… RemarksEnter system view system-view —Enable CDP compatibility globally lldp compliance cdp RequiredDisabled by default.EnterEthernetinterfaceview or portgroup viewEnter Layer 2Ethernet interfaceviewinterface interface-type interface-number RequiredUse either command.Enter port groupview port-group manual port-group-nameConfigure CDP-compatible LLDP tooperate in TxRx mode lldp compliance admin-status cdp txrx RequiredDisable mode by defaultCAUTION:The maximum TTL value allowed by CDP is 255 seconds. To make CDP-compatible LLDP work properlywith Cisco IP phones, make sure that the product of the TTL multiplier and the LLDPDU transmit interval isless than 255 seconds.Configuring LLDP trappingLLDP trapping notifies the network management system (NMS) of events such as newly-detectedneighboring devices and link malfunctions.To prevent excessive LLDP traps from being sent when topology is unstable, you can set a minimum trapsending interval for LLDP.Follow these steps to configure LLDP trapping:To do… Use the command… RemarksEnter system view system-view —
