XS1930 Series User’s Guide
114
C
HAPTER
9
VLAN
9.1 Overview
This chapter shows you how to configure 802.1Q tagged and port-based VLANs. The type of screen you
see here depends on the
VLAN Type
you selected in the
Switch Setup
screen.
9.1.1 What You Can Do
• Use the
VLAN Status
) to view and search all VLAN groups.
• Use the
VLAN Detail
) to view detailed port settings and status of the
VLAN group.
• Use the
Static VLAN Setup
screen (
) to configure and view 802.1Q VLAN
parameters for the Switch.
• Use the
VLAN Port Setup
) to configure the static VLAN (IEEE 802.1Q)
settings on a port.
• Use the
Voice VLAN Setup
screen (
) to set up VLANs that allow you to group
voice traffic with defined priority and enable the switch port to carry the voice traffic separately from
data traffic to ensure the sound quality does not deteriorate.
• Use the
Vendor ID Based VLAN Setup
) to set up VLANs that allow you
to group untagged packets into logical VLANs based on the source MAC address of the packet. You
can specify a mask for the MAC address to create a MAC address filter and enter a weight to set the
VLAN rule’s priority.
• Use the
Port-Based VLAN
screen (
) to set up VLANs where the packet
forwarding decision is based on the destination MAC address and its associated port.
9.1.2 What You Need to Know
Read this section to know more about VLAN and how to configure the screens.
IEEE 802.1Q Tagged VLANs
A tagged VLAN uses an explicit tag (VLAN ID) in the MAC header to identify the VLAN membership of a
frame across bridges - they are not confined to the switch on which they were created. The VLANs can
be created statically by hand or dynamically through GVRP. The VLAN ID associates a frame with a
specific VLAN and provides the information that switches need to process the frame across the network.
A tagged frame is four bytes longer than an untagged frame and contains two bytes of TPID (Tag
Protocol Identifier, residing within the type/length field of the Ethernet frame) and two bytes of TCI (Tag
Control Information, starts after the source address field of the Ethernet frame).
The CFI (Canonical Format Indicator) is a single-bit flag, always set to zero for Ethernet switches. If a
frame received at an Ethernet port has a CFI set to 1, then that frame should not be forwarded as it is to
an untagged port. The remaining twelve bits define the VLAN ID, giving a possible maximum number of
4,096 VLANs. Note that user priority and VLAN ID are independent of each other. A frame with VID