User guide

6-2 E
XTREME
W
ARE
S
OFTWARE
U
SER
G
UIDE
V
IRTUAL
LAN
S
(VLAN
S
)
B
ENEFITS
Implementing VLANs on your networks has the following advantages:
• VLANs help to control traffic.
With traditional networks, congestion can be caused by broadcast traffic that is
directed to all network devices, regardless of whether they require it. VLANs
increase the efficiency of your network because each VLAN can be set up to contain
only those devices that must communicate with each other.
• VLANs provide extra security.
Devices within each VLAN can only communicate with member devices in the same
VLAN. If a device in VLAN Marketing must communicate with devices in VLAN
Sales, the traffic must cross a routing device.
• VLANs ease the change and movement of devices.
With traditional networks, network administrators spend much of their time dealing
with moves and changes. If users move to a different subnetwork, the addresses of
each endstation must be updated manually.
T
YPES OF
VLAN
S
VLANs can be created according to the following criteria:
• Physical port
• 802.1Q tag
• Ethernet, LLC SAP, or LLC/SNAP Ethernet protocol type
• MAC address
• A combination of these criteria
P
ORT
-B
ASED
VLAN
S
In a port-based VLAN, a VLAN name is given to a group of one or more ports on the
switch. A port can be a member of only one port-based VLAN.
For example, on the Summit7i switch in Figure 6-1, ports 9 through 14 are part of
VLAN Marketing; ports 25 through 29 are part of VLAN Sales; and ports 21 through 24
and 30 through 32 are in VLAN Finance.