26 C
HAPTER
 1: S
UPER
S
TACK
II S
WITCH
 M
ANAGEMENT
 S
OFTWARE
Broadcast Storm
Control
Your Switch supports Broadcast Storm Control, a system that 
automatically creates an alarm for each port to monitor the level of 
broadcast traffic on that port. 
If the broadcast traffic level rises to 2976 
frames per 
second, the broadcast traffic on the port is blocked until the 
broadcast
 traffic level drops to 1488 frames per second. 
This system 
prevents the overwhelming broadcast traffic that can result from network 
equipment which is faulty or configured incorrectly.
For more information about enabling Broadcast Storm Control, see 
“Configuring the Advanced Stack Settings”
 on 
page 76
.
Virtual LANs
Your Switch provides supports for up to 16 Virtual LANs (VLANs). A VLAN 
is a flexible group of devices that can be located anywhere in a network, 
but they communicate as if they are on the same physical segment. With 
VLANs, you can segment your network without being restricted by 
physical connections — a drawback of traditional network design. As an 
example, with VLANs you can segment your network according to:
■
Departmental groups
 — For example, you can have one VLAN for 
the Marketing department, another for the Finance department, and 
another for the Development department. 
■
Hierarchical groups
 — For example, you can have one VLAN for 
directors, another for managers, and another for general staff.
■
Usage groups
 — For example, you can have one VLAN for users of 
e-mail, and another for users of multimedia.
For more information, see 
“Virtual LANs (VLANs)”
 on 
page 163
.
FastIP
Your Switch supports FastIP, a system that reduces the load on routing 
devices when VLANs are implemented on your network. 
Devices within different VLANs can only communicate using a routing 
device; if there is a large amount of inter-VLAN traffic, the router can 
become overloaded and network performance can be affected. FastIP 
allows your endstations and Switch units to find secure short-cuts for 
inter-VLAN traffic that bypass the routing device altogether.
For more information about FastIP, see 
“FastIP”
 on 
page 181
.