H3C Technologies H3C S12500 Series Switches - Manual (Page 248)

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An MRP participant sends Join messages when it wishes to declare its attribute values and receives
Join messages from other MRP participants. When receiving a Join message, an MRP participant
sends a Join message to all participants except the sender.
Join messages include the following types:
{
JoinEmpty—An MRP participant sends JoinEmpty messages to declare attribute values that it
has not registered.
{
JoinIn—An MRP participant sends JoinIn messages to declare attribute values that it has
registered.
• New message
When the Multiple Spanning Tree Protocol (MSTP) topology changes, in other words, when an
MSTP TcDetected event occurs, an MRP participant sends New messages to declare the topology
change. On receiving a New message, an MRP participant sends a New message out of each
port except the receiving port. Similar to a Join message, a New message enables MRP
participants to register attributes.
• Leave message
An MRP participant sends Leave messages when it wishes to withdraw declarations of its attribute
values and receives Leave messages from other participants. 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 deregister all attributes, so that any other MRP
participant can 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. On sending a
LeaveAll message, MRP restarts the LeaveAll timer.
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 send MRP messages.
• Join timer
The Join timer control the transmission of Join messages. To make sure 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
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.