R0106-HP MSR Router Series Interface Configuration Guide(V7)

7
After a flapping interface is dampened, it does not report its state changes to the CPU. For state change
events, the interface only generates SNMP notifications and log messages.
Parameters
• Penalty—The interface has a initiate penalty of 0. When the interface flaps, it is assigned a penalty
of 1000 for each down even, and does not increase for up events.
• Ceiling—The penalty stops increasing after it reaches the ceiling.
• Suppress-limit—The accumulated penalty that triggers the device to dampen the interface. In
dampened state, the interface does not report its state changes to the CPU. For state change events,
the interface only generates SNMP notifications and log messages
• Reuse-limit—When the accumulated penalty decreases to this reuse threshold, the interface is not
dampened. Interface state changes are reported to the higher layers. For each state change, the
system also generates an SNMP notification and log message.
• Decay—The amount of time (in seconds) after which a penalty is decreased.
• Max-suppress-time—The maximum amount of time the interface can be dampened. If the penalty
is still higher than the reuse threshold when this timer expires, the penalty stops increasing for down
events.
The maximum penalty is equal to 2
(Max-suppress-time/Decay)
× reuse-limit. It is not user configurable.
Figure 1 shows the change rule of the penalty value. t
0
and t
2
indicate the start time and end time of the
suppression, respectively. The period from t
0
to t
2
indicates the suppression period, t
0
to t
1
indicates the
max-suppress-time, and t
1
to t
2
indicates the complete decay period.
Figure 1 Change rule of the penalty value
Configuration restrictions and guidelines
The dampening command does not take effect on the administratively down events. When you execute
the shutdown command, the penalty restores to 0, and the interface reports the down event to the higher
layer protocols.
Not suppressed Not suppressedSuppressed
Penalty
Time
Reuse limit
Suppress limit
Ceiling
t
0 t1 t2