DES-3550 Layer 2
Fast Ethernet Switch User’s Guide
79
Traffic Control
Use the
Traffic Control
menu to enable or disable storm control and adjust the threshold for
multicast and broadcast storms, as well as DLF (Destination Look Up Failure). Traffic control
settings are applied to individual Switch modules. To view the following window, Open the
QoS folder and click the
Traffic control
link:
Figure 6- 28. Traffic Control Settings and Traffic Control Table window
Traffic or storm control is used to stop broadcast, multicast, or ARP request storms that may
result when a loop is created. The
Destination Look Up Failure
control is a method of
shutting down a loop when a storm is formed because a MAC address cannot be located in the
Switch’s forwarding database and it must send a packet to all ports or all ports on a VLAN.
To configure Traffic Control, first select a group of ports by using the
Group
pull down
menu. As seen in the figure above, this section is set by 8 specified groups of ports on the
Switch.
Group 1
refers to ports 1 through 8;
Group 2
refers to ports 9 through 16;
Group 3
refers to ports 17 through 24;
Group 4
refers to ports 25 through 32;
Group 5
refers to ports
33 through 40;
Group 6
refers to ports 41 through 48;
Group 7
refers to mini GBIC port 49;
Group 8
refers to mini GBIC port 50.
Broadcast Storm
,
Multicast Storm
, and
Destination
Unknown
may be
Enabled
or
Disabled
for either group. The
Threshold
value is the upper
threshold at which the specified traffic control is switched on. This is the number of
Broadcast, Multicast, or DLF packets, in Kbps, received by the Switch that will trigger the
storm traffic control measures. The Threshold value can be set from 0 to 255 packets. The
default setting is 128. The settings of each port may be viewed in the
Traffic Control Table
in the same window. Click
Apply
to implement changes made.
802.1p Default Priority
The Switch allows the assignment of a default 802.1p priority to each port on the Switch. In
the
Configuration
folder open the
QoS
folder and click
802.1p Default Priority
, to view the
screen shown below.