H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 205)

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{
When receiving a Leave message, an MRP participant sends a Leave message to all
participants except the sender.
• LeaveAll message
{
Each MRP participant is configured with an individual LeaveAll timer. When the timer expires,
the MRP participant sends LeaveAll messages to the remote participants, so that the local
participant and the remote participants deregister all attributes and re-register all attributes. This
process periodically clears the useless attributes in the network.
{
On receiving a LeaveAll message, MRP determines whether to send a Join message to request
the sender to re-register these attributes according to attribute status.
MRP timers
The implementation of MRP uses the following timers to control MRP message transmission.
• Periodic timer
On startup, an MRP participant starts its own Periodic timer to control MRP message transmission.
The MRP participant collects the MRP messages to be sent before the Periodic timer expires, and
sends the MRP messages in as few packets as possible when the Periodic timer expires and
meanwhile restarts the Periodic timer. This mechanism reduces the number of MRP protocol
packets periodically sent.
You can enable or disable the Periodic timer at the CLI. When you disable the Periodic timer, MRP
will not periodically send MRP messages, and MRP messages are sent only when the LeaveAll
timer expires or the local participant receives LeaveAll messages from a remote participant.
• Join timer
The Join timer controls the transmission of Join messages. To make sure that Join messages can be
reliably transmitted to other participants, an MRP participant waits for a period of the Join timer
after sending a Join message. If the participant receives JoinIn messages from other participants
and the attributes in the JoinIn messages are the same as the sent Join messages before the Join
timer expires, the participant does not re-send the Join message. When both the Join timer and the
Periodic timer expire, the participant re-sends the Join message.
• Leave timer
The Leave timer controls the deregistration of attributes. When an MRP participant wishes other
participants to deregister its attributes, it sends a Leave message. On receiving a Leave message,
MRP starts the Leave timer, and deregisters the attributes if it does not receive any Join message for
the attributes before the Leave timer expires. When an MRP participant sends or receives LeaveAll
messages, it starts the Leave timer. MRP deregisters the attributes in the LeaveAll messages if it
does not receive any Join message for the attributes before the Leave timer expires.
• LeaveAll timer
On startup, an MRP participant starts its own LeaveAll timer. When the LeaveAll timer expires,
MRP sends out a LeaveAll message and restarts the LeaveAll timer. On receiving the LeaveAll
message, other participants re-register all the attributes and re-start their LeaveAll timer.
When you configure the MRP timers, follow these guidelines:
• When the LeaveAll timer of an MRP participant expires, the MRP participant sends LeaveAll
messages to the remote participants. On receiving a LeaveAll message, a remote participant
restarts its LeaveAll timer, and stops sending out LeaveAll messages. This mechanism effectively
reduces the number of LeaveAll messages in the network.
• To avoid the case that the LeaveAll timer of a fixed participant always first expires, the switch
randomly changes the LeaveAll timer within a certain range when the MRP participant restarts its
LeaveAll timer.