613. LSP establishment and maintenanceLDP sends label requests and label binding messages between LDP peers to establish LSPs.For the LSP establishment process, see "LSP establishment and label distribution."4. Session terminationAn LSR terminates its LDP session with an LDP peer in the following cases:{ All Hello adjacencies deleted between the two peersLDP peers periodically send Hello messages to indicate that they intend to keep the Helloadjacency. If an LSR does not receive any Hello message from a peer before the Hello timerexpires, it deletes the Hello adjacency with this peer. An LDP session has one or more Helloadjacencies. When the last Hello adjacency for the session is deleted, the LSR will send aNotification message to terminate the LDP session.{ Loss of session connectivityAn LSR determines the integrity of an LDP session according to the LDP PDU (which carries oneor more LDP messages) transmitted on the session. Before the Keepalive timer times out, if twoLDP peers have no information to exchange, they can send Keepalive messages to each otherto maintain the LDP session. If an LSR does not receive any LDP PDU from its peer during aKeepalive interval, it closes the TCP connection and terminates the LDP session.{ Receiving a shutdown message from the peerAn LSR can also send a Shutdown message to its LDP peer to terminate the LDP session.Therefore, when receiving the Shutdown message from an LDP peer, an LSR terminates thesession with the LDP peer.Protocols• RFC 3031, Multiprotocol Label Switching Architecture• RFC 3032, MPLS Label Stack Encoding• RFC 5036, LDP SpecificationMPLS configuration task listTask RemarksEnabling the MPLS function RequiredConfiguring a static LSP RequiredUse either the staticor dynamic LSPconfigurationmethodEstablishing dynamic LSPsthrough LDPConfiguring MPLS LDP capability RequiredConfiguring local LDP sessionparameters OptionalConfiguring remote LDP sessionparameters OptionalConfiguring PHP OptionalConfiguring the policy for triggeringLSP establishment OptionalConfiguring the label distributioncontrol mode Optional
