180MRP deregisters all attributes that have not been re-registered to periodically clear useless attributes inthe network.MRP timersMRP uses the following timers to control message transmission.Periodic timerThe Periodic timer controls the transmission of MRP messages. An MRP participant starts its own Periodictimer upon startup, and stores MRP messages to be sent before the Periodic timer expires. When thePeriodic timer expires, it sends stored MRP messages in as few packets as possible and restarts thePeriodic timer. This mechanism reduces the number of MRP packets periodically sent.You can enable or disable the Periodic timer at the CLI. If you disable the Periodic timer, MRP does notperiodically send MRP messages. Instead, MRP sends MRP messages when the LeaveAll timer expires orit receives a LeaveAll message from the peer participant.Join timerThe Join timer controls the transmission of Join messages. An MRP participant starts the Join timer aftersending a Join message to the peer participant. If it receives a JoinIn message from another participantthat has the same attributes as the sent Join message before the Join timer expires, the participant doesnot re-send the Join message. When both the Join timer and the Periodic timer expire, the participantre-sends the Join message.Leave timerThe Leave timer controls the deregistration of attributes. Upon receiving a Leave message, MRP starts theLeave timer. If it receives a Join message for the attributes in the Leave message before the Leave timerexpires, MRP does not deregister the attributes. In addition, when an MRP participant sends or receivesa LeaveAll message, it starts the Leave timer. If it receives a Join message for some attributes in theLeaveAll message before the Leave timer expires, MRP does not deregister the specific attributes.Otherwise, MRP deregisters the attributes.LeaveAll timerAfter startup, an MRP participant starts its own LeaveAll timer. When the LeaveAll timer expires, MRPsends out a LeaveAll message and restarts the LeaveAll timer. After receiving the LeaveAll message, otherparticipants re-start their LeaveAll timer.When its LeaveAll timer expires, an MRP participant sends a LeaveAll message to other participants.Upon receiving a LeaveAll message, a participant restarts its LeaveAll timer, and stops sending outLeaveAll messages. This mechanism effectively reduces the number of LeaveAll messages in the network.To avoid the case that the LeaveAll timer of a participant always first expires, the system randomlychanges the LeaveAll timer within a certain range for an MRP participant when the participant restarts itsLeaveAll timer.MVRP registration modesVLAN information propagated by MVRP includes dynamic VLAN information from other devices andlocal static VLAN information.MVRP has the following registration modes, which process static and dynamic VLANs in different ways.
