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Configuring VLANs
Page 107
Section 9. Configuring VLANs
VLANs are logical subgroups with a Local Area Network (LAN) which combine user stations and network devices
into a single unit, regardless of the physical LAN segment to which they are attached. VLANs allow network traffic
to flow more efficiently within subgroups. VLANs use software to reduce the amount of time it takes for network
changes, additions, and moves to be implemented.
VLANs have no minimum number of ports, and can be created per unit, per device, or through any other logical
connection combination, since they are software-based and not defined by physical attributes.
VLANs function at Layer 2. Since VLANs isolate traffic within the VLAN, a Layer 3 router working at a protocol
level is required to allow traffic flow between VLANs. Layer 3 routers identify segments and coordinate with
VLANs. VLANs are Broadcast and Multicast domains. Broadcast and Multicast traffic is transmitted only in the
VLAN in which the traffic is generated.
VLAN tagging provides a method of transferring VLAN information between VLAN groups. VLAN tagging attaches
a 4-byte tag to packet headers. The VLAN tag indicates to which VLAN the packets belong. VLAN tags are
attached to the VLAN by either the end station or the network device. VLAN tags also contain VLAN network prior-
ity information.
Combining VLANs and GARP (Generic Attribute Registration Protocol) allows network managers to define net-
work nodes into Broadcast domains.
This section contains the following topics:
•
Defining VLAN Properties
•
Defining VLAN Membership
•
Defining VLAN Interface Settings
•
Defining Private VLANs
•
Configuring GARP