Qos->Rate Limiting->Storm Control Configuration - Symbol ES3000 User Manual

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4.2.50 QoS->Rate Limiting->Storm Control Configuration
Rate limiting, or storm control, prevents ports on the ES3000 switch from being overwhelmed by a
broadcast, unicast, or multicast storm. A storm results when packets flood the LAN, which degrades
network performance. With rate limiting enabled, the switch monitors incoming traffic by counting
packets over a period of time. When the packet count exceeds a predefined threshold level, the
switch suppresses traffic until the packet count drops below the threshold. With rate limiting
disabled, all traffic is allowed. The switch supports rate limiting for broadcast, multicast, and unicast
(DLF) traffic, keeping a separate count of the packets for each type of traffic. When broadcast or
unicast traffic reaches the threshold, the switch suppresses further traffic of that type until traffic
falls below the threshold.
Use the Storm Control Configuration page to set the limitation of Broadcast, Multicast, and/or DLF
(Destination Look Failure) packets delivered to the CPU. Each kind of packet determines the network
load. When the load reaches a certain threshold, the CPU is busy handling packets and is unable to
respond to other requests (configuration commands or SNMP requests). Available network
bandwidth decreases. The administrator can enable storm control to limit traffic in the networks.
Broadcast, multicast, and/or DLF traffic cannot be set on a per-port basis, only on a per-switch basis.
If a threshold value is defined, that value applies to DLF, Broadcast and Multicast traffic (if enabled)
and is in no way shared between the traffic types. Click Apply to implement the threshold value for
the enabled data types. Storm Control is enabled globally and cannot be defined on a per-port basis.