xStack
®
DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch
220
Traffic Control
On a computer network, packets such as
Multicast packets and Broadcast 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.
Figure 6 - 2 Traffic Control Settings window
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, the only 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. To utilize this method of Storm Control, choose the
Shutdown
option of the
Action
field in the
window below.
Use the
Traffic Control
window to enable or disable storm control and adjust the threshold for multicast and broadcast storms, as
well as DLF (Destination Look Up Failure).
To view the following window, click
Security > Traffic Control
, as shown above:
To configure
Traffic Control
, enable or disable the
Broadcast Storm
,
Multicast Storm
and
DLF
using their corresponding pull-
down menus. Click
Apply
to implement changes made.
Parameter Description
Traffic Control Recover
Unit
Choose the Switch ID number of the Switch in the switch stack to be modified.
From/To
Select the ports to be shutdown.
Traffic Trap Configuration
Traffic Trap
Enable sending of Storm Trap messages when the type of action taken by the Traffic Control function
in handling a Traffic Storm is one of the following:
•
None
– Will not send Storm trap warning messages regardless of action taken by the
Traffic Control mechanism.
•
Storm Occurred
– Will send Storm Trap warning messages upon the occurrence of a
