D-Link xStack Reference Manual page 467

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xStack DGS-3620 Series Layer 3 Managed Stackable Gigabit Switch Web UI Reference Guide
For every consecutive checking interval that reveals a packet flooding issue, the Switch will double the time it will
discard ingress ARP and IP broadcast packets and packets from the illegal IP addresses. In the example above,
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:
Figure 9-86 Mapping QoS on the Switch
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