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DGS-3700 Series Layer 2 Managed Gigabit Ethernet Switch CLI Reference Guide
P
S
ACKET
TORM
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On a computer network, packets such as Multicast, Broadcast, and Unicast packets continually flood the
network as normal procedure. At times, this traffic may increase do to a malicious endstation on the network
or a malfunctioning device, such as a faulty network card. Thus, switch throughput problems will arise and
consequently affect the overall performance of the switch network. To help rectify this packet storm, the
Switch will monitor and control the situation.
The packet storm is monitored to determine if too many packets are flooding the network, based on the
threshold level provided by the user. Once a packet storm has been detected, the Switch will drop packets
coming into the Switch until the storm has subsided. This method can be utilized by selecting the Drop
option of the Action field in the window below.
The Switch will also scan and monitor packets coming into the Switch by monitoring the Switch's chip
counter. This method is only viable for Broadcast and Multicast storms because the chip only has counters
for these two types of packets. Once a storm has been detected (that is, once the packet threshold set below
has been exceeded), the Switch will shutdown the port to all incoming traffic with the exception of STP
BPDU packets, for a time period specified using the countdown field. If this field times out and the packet
storm continues, the port will be placed in a Shutdown Forever mode which will produce a warning message
to be sent to the Trap Receiver. Once in Shutdown Forever mode, one method of recovering this port is to
manually recoup it using the Port Configuration window in the Administration folder and selecting the
disabled port and returning it to an Enabled status and the port will be recovered automatically , when auto-
recover time is over. To utilize this method of Storm Control, choose the Shutdown option of the Action
field in the window below.
The broadcast storm control commands in the Command Line Interface (CLI) are listed (along with the
appropriate parameters) in the following table.
C
OMMAND
config traffic
control
show traffic control
config traffic trap
config traffic control
auto_recover_time
config traffic
control log state
Each command is listed, in detail, in the following sections.
config traffic control
Purpose
Syntax
Description
C
OMMANDS
P
ARAMETERS
[<portlist> | all] {broadcast [enable | disable] | multicast [enable | disable] | unicast
[enable | disable] | action [drop | shutdown] | threshold <value 0-255000>
|countdown [ <min 0> | <min 3-30>]| time_interval <sec 5-600>}
{<portlist>}
[none | storm_occurred | storm_cleared | both]
[ <min 0> | <min 1-65535> ]
[enable | disable]
Used to configure broadcast/multicast/unicast packet storm control. The software
mechanism is provided to monitor the traffic rate in addition to the hardware storm
control mechanism previously provided.
config traffic control [<portlist> | all] {broadcast [enable | disable] | multicast
[enable | disable] | unicast [enable | disable] | action [drop | shutdown] |
threshold <value 0-255000> |countdown [ <min 0> | <min 3-30>]|
time_interval <sec 5-600>}
This command is used to configure broadcast/multicast/unicast storm control. By
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