Brocade Virtual ADX Switch and Router Guide (Supporting ADX v03.1.00) - Manual (Page 38)

24 Brocade Virtual ADX Switch and Router Guide
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Overview
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FIGURE 1 Brocade device containing user-defined Layer 2 port-based VLAN
A port can belong to only one port-based VLAN, unless you apply 802.1q tagging to the port.
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.
Since 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.