H3C Technologies H3C S10500 Series Switches - Manual (Page 173)

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A GARP participant sends Join messages when it wishes to declare its attribute values or receives Join
messages from other GARP participants.
Join messages fall into JoinEmpty and JoinIn. A GARP participant sends JoinEmpty messages to declare
attribute values that it has not registered. It sends JoinIn messages to declare attribute values that it has
registered.
2. Leave messages
A GARP participant sends Leave messages when it wishes to withdraw declarations of its attribute values
(because, for example, it has deregistered its attribute values), or receives Leave messages from other
participants.
Leave messages fall into LeaveEmpty and LeaveIn. A GARP participant sends LeaveEmpty messages to
withdraw declarations of the attribute values that it has not registered. It sends LeaveIn messages to
withdraw declarations of the attribute values that it has registered.
3. LeaveAll messages
A GARP participant sends a LeaveAll message when it declares that it is deregistering all attribute values
or receives LeaveAll messages from other participants. If any participants want to maintain the
registration for a particular attribute value, they must send a Join message.
GARP timers
NOTE:
•
The settings of GARP timers apply to all GARP applications, such as GVRP, on a LAN.
• On a GARP-enabled network, each port maintains its own Hold, Join, and Leave timers, but only one
LeaveAll timer is maintained on each device. This LeaveAll timer applies to all ports on the device.
• The value ranges for the Hold, Join, Leave, and LeaveAll timers are dependent on one another. See
Table 20 for their dependencies.
H3C's implementation of GARP uses the following timers to control GARP message transmission:
1. Hold timer
The Hold timer sets the delay that a GARP participant waits before sending a Join or Leave message.
When an attribute value changes or a Join or Leave message arrives, the GARP participant does not
send the message immediately. Rather, it assembles Join and Leave messages in the least number of
GARP PDUs, and sends them out when the Hold timer expires. This timer reduces the number of GARP
PDUs and saves bandwidth.
2. Join timer
A GARP participant might declare an attribute twice to ensure reliable transmission. The Join timer sets
the interval between the two declarations.
A GARP participant starts a Join timer when it declares an attribute value or receives a JoinIn message
for the attribute value. If the GARP participant does not receive any declaration for the attribute value
when the Join timer expires, it re-declares the attribute value.
NOTE:
Because all attributes of a GARP participant share the same Join timer, you must set the Join timer long
enough so that all attributes can be sent out in one declaration.
3. Leave timer