D-Link xStack DGS-3420 Series Reference Manual page 314

xStack® DGS-3420 Series Layer 2 Managed Stackable Gigabit Switch Web UI Reference Guide
the Switch doubled the time for dropping ARP and IP broadcast packets when consecutive flooding issues were
detected at 5-second intervals. (First stop = 5 seconds, second stop = 10 seconds, third stop = 20 seconds) Once
the flooding is no longer detected, the wait period for dropping ARP and IP broadcast packets will return to 5
seconds and the process will resume.
In Fuzzy mode, once the Safeguard Engine has entered the Exhausted mode, the Safeguard Engine will decrease
the packet flow by half. After returning to Normal mode, the packet flow will be increased by 25%. The switch will
then return to its interval checking and dynamically adjust the packet flow to avoid overload of the Switch.
NOTICE: When Safeguard Engine is enabled, the Switch will allot bandwidth to various traffic flows
(ARP, IP) using the FFP (Fast Filter Processor) metering table to control the CPU utilization
and limit traffic. This may limit the speed of routing traffic over the network.
Users can enable the Safeguard Engine or configure advanced Safeguard Engine settings for the Switch.
To view this window, click Security > Safeguard Engine Settings as shown below:
The fields that can be configured are described below:
Parameter
Safeguard Engine
State
Rising Threshold (20%
- 100%)
Falling Threshold (20%
- 100%)
Trap / Log
Mode
Figure 8-81 Safeguard Engine Settings window
Description
Use the radio button to globally enable or disable Safeguard Engine settings for the
Switch.
Used to configure the acceptable level of CPU utilization before the Safeguard
Engine mechanism is enabled. Once the CPU utilization reaches this percentage
level, the Switch will move into Exhausted mode, based on the parameters provided
in this window.
Used to configure the acceptable level of CPU utilization as a percentage, where the
Switch leaves the Safeguard Engine state and returns to normal mode.
Use the drop-down menu to enable or disable the sending of messages to the
device's SNMP agent and switch log once the Safeguard Engine has been activated
by a high CPU utilization rate.
Used to select the type of Safeguard Engine to be activated by the Switch when the
CPU utilization reaches a high rate. The user may select:
Fuzzy – If selected, this function will instruct the Switch to minimize the IP and ARP
traffic flow to the CPU by dynamically allotting an even bandwidth to all traffic flows.
Strict – If selected, this function will stop accepting all ARP packets not intended for
the Switch, and will stop receiving all unnecessary broadcast IP packets, until the
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