1-6DLDP implementation1) If the DLDP-enabled link is up, DLDP sends DLDP packets to the peer device, and analyzes andprocesses the DLDP packets received from the peer device. DLDP in different states sendsdifferent types of packets.Table 1-5 Types of packets sent by DLDPDLDP state Packet typeActive Advertisement packets, including those with or without an RSY tagAdvertisement Advertisement packetsProbe Probe packets2) DLDP analyzes and processes received packets from the peer device as follows:z In authentication mode, DLDP authenticates the packets, and discards those failing to pass theauthentication.z DLDP processes the received DLDP packets.Table 1-6 Process received DLDP packetsPacket type Processing procedureIf this neighbor entry does not exist on the local device, DLDPcreates the neighbor entry, enables the entry aging timer, andswitches to the probe state.AdvertisementpacketExtracts neighborinformationIf the neighbor entry already exists on the local device, DLDPupdates the entry aging timer.Flush packet Deletes the neighbor entry from the local deviceCreates the neighbor entry if this neighbor entry does not existon the local device.Probe packetSends echo packetscontaining bothneighbor and its owninformation to the peer If the neighbor entry already exists on the local device, updatesthe entry aging timer.No Discards this echo packetNo Discards this echo packetSets the neighbor flag bit tobidirectional linkEcho packetCheckswhether thelocal deviceis in theprobe stateYesCheckswhetherneighborinformation inthe packet isthe same asthat on thelocal deviceYes If all neighbors are in thebidirectional link state, DLDPswitches from the probe state to theadvertisement state, and sets theecho waiting timer to 0.3) If no echo packet is received from the neighbor, DLDP performs the following processing:
