H3C Technologies H3C S5560 Series Switches - Manual (Page 218)

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• Declaration—Includes Join and New messages.
• Withdrawal—Includes Leave and LeaveAll messages.
Join message
An MRP participant sends a Join message to request the peer participant to register attributes in the Join
message.
When receiving a Join message from the peer participant, an MRP participant performs the following
tasks:
• Registers the attributes in the Join message.
• Propagates the Join message to all other participants on the device.
After receiving the Join message, other participants send the Join message to their respective peer
participants.
Join messages sent from a local participant to its peer participant include the following types:
• JoinEmpty—Declares an unregistered attribute. For example, when an MRP participant joins an
unregistered static VLAN, it sends a JoinEmpty message.
VLANs created manually and locally are called static VLANs. VLANs learned through MRP are
called dynamic VLANs.
• JoinIn—Declares a registered attribute. A JoinIn message is used in one of the following situations:
{
An MRP participant joins an existing static VLAN and sends a JoinIn message after registering
the VLAN.
{
The MRP participant receives a Join message propagated by another participant on the device
and sends a JoinIn message after registering the VLAN.
New message
Similar to a Join message, a New message enables MRP participants to register attributes.
When the MSTP topology changes, an MRP participant sends a New message to the peer participant to
declare the topology change.
Upon receiving a New message from the peer participant, an MRP participant performs the following
tasks:
• Registers the attributes in the message.
• Propagates the New message to all other participants on the device.
After receiving the New message, other participants send the New message to their respective peer
participants.
Leave message
An MRP participant sends a Leave message to the peer participant when it wants the peer participant to
deregister attributes that it has deregistered.
When the peer participant receives the Leave message, it performs the following tasks:
• Deregisters the attribute in the Leave message.
• Propagates the Leave message to all other participants on the device.
After a participant on the device receives the Leave message, it determines whether to send the Leave
message to its peer participant depending on the attribute status on the device.
• If the VLAN in the Leave message is a dynamic VLAN not registered by any participants on the
device, both of the following events occur: