PowerConnect B-Series FCX Configuration Guide 429
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VLAN overview 13
NOTE
VLAN IDs 4087, 4090, and 4093 are reserved for Dell internal use only. VLAN 4094 is reserved for
use by Single STP. Also, if you are running an earlier release, VLAN IDs 4091 and 4092 may be
reserved for Dell internal use only. If you want to use VLANs 4091 and 4092 as configurable VLANs,
you can assign them to different VLAN IDs. For more information, refer to “Assigning different VLAN
IDs to reserved VLANs 4091 and 4092” on page445.
Each port-based VLAN can contain either tagged or untagged ports. A port cannot be a member of
more than one port-based VLAN unless the port is tagged. 802.1Q tagging allows the port to add a
four-byte tag field, which contains the VLAN ID, to each packet sent on the port. You also can
configure port-based VLANs that span multiple devices by tagging the ports within the VLAN. The
tag enables each device that receives the packet to determine the VLAN the packet belongs to.
802.1Q tagging applies only to Layer 2 VLANs, not to Layer 3 VLANs.
Because each port-based VLAN is a separate Layer 2 broadcast domain, by default each VLAN runs
a separate instance of the Spanning Tree Protocol (STP).
Layer 2 traffic is bridged within a port-based VLAN and Layer 2 broadcasts are sent to all the ports
within the VLAN.
Figure 86 shows an example of a Dell PowerConnect device on which a Layer 2 port-based VLAN
has been configured.