1-5Timer DescriptionEntry aging timerWhen a new neighbor joins, a neighbor entry is created and thecorresponding entry aging timer is enabledWhen an advertisement packet is received from a neighbor, theneighbor entry is updated and the corresponding entry aging timer isupdatedIn the normal mode, if no packet is received from the neighbor whenthe entry aging timer expires, DLDP sends an advertisement packetwith an RSY tag, and deletes the neighbor entry.In the enhanced mode, if no packet is received from the neighborwhen the entry aging timer expires, DLDP enables the enhancedtimerThe entry aging timer length is three times the advertisement timerlength.Enhanced timerIn the enhanced mode, if no packet is received from the neighborwhen the entry aging timer expires, DLDP enables the enhancedtimer for the neighbor. The enhanced timer length is 10 secondsThe enhanced timer then sends one probe packet every second andeight packets successively to the neighbor.If no echo packet is received from the neighbor when the enhancedtimer expires, the state of the local end is set to unidirectionalcommunication state and the state machine turns into the disablestate. DLDP outputs log and tracking information and sends flushpackets. Depending on the user-defined DLDP down mode, DLDPdisables the local port automatically or prompts you to disable the portmanually. Meanwhile, DLDP deletes the neighbor entry.DelayDown timerWhen a device in the active, advertisement, or probe DLDP statereceives a port down message, it does not removes thecorresponding neighbor immediately, neither does it changes to theinactive state. Instead, it changes to the delaydown state first.When a device changes to the delaydown state, the related DLDPneighbor information remains, and the DelayDown timer is triggered.The DelayDown timer is configurable and ranges from 1 to 5 seconds.A device in the delaydown state only responds to port up messages.A device in the delaydown state resumes its original DLDP state if itreceives a port up message before the delaydown timer expires.Otherwise, it removes the DLDP neighbor information and changes tothe inactive state.DLDP Operating ModeDLDP can operate in two modes: normal mode and enhanced mode, as described below.z In normal DLDP mode, when an entry timer expires, the device removes the correspondingneighbor entry and sends an Advertisement packet with RSY tag.z In enhanced DLDP mode, when an entry timer expires, the Enhanced timer is triggered and thedevice sends up to eight Probe packets at a frequency of one packet per second to test theneighbor. If no Echo packet is received from the neighbor when the Echo timer expires, the devicetransits to the Disable state.
