Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 321)

PVST+ configuration examples
The following examples show configuration examples for two common configurations:
• Untagged IEEE 802.1Q BPDUs on VLAN 1 and tagged PVST+ BPDUs on other VLANs
• Tagged IEEE 802.1Q BPDUs on VLAN 1 and untagged BPDUs on another VLAN
Tagged port using default VLAN 1 as its port native VLAN
The following table shows an example of a PVST+ configuration that uses VLAN 1 as the untagged
default VLAN and VLANs 2, 3, and 4 as tagged VLANs.
FIGURE 68 Default VLAN 1 for untagged BPDU
To implement this configuration, enter the following commands.
Commands on the Brocade Device
device(config)#vlan-group 1 vlan 2 to 4
device(config-vlan-group-1)#tagged ethernet 1/1
device(config-vlan-group-1)#exit
device(config)#interface ethernet 1/1
device(config-if-1/1)#dual-mode
device(config-if-1/1)#pvst-mode
These commands configure a VLAN group containing VLANs 2, 3, and 4, add port 1/1 as a tagged port
to the VLANs, and enable the dual-mode feature and PVST+ support on the port. The dual-mode
feature allows the port to send and receive untagged frames for the default VLAN (VLAN 1 in this case)
in addition to tagged frames for VLANs 2, 3, and 4. Enabling the PVST+ support ensures that the port is
ready to send and receive PVST+ BPDUs. If you do not manually enable PVST+ support, the support is
not enabled until the port receives a PVST+ BPDU.
The configuration leaves the default VLAN and the port Port Native VLAN unchanged. The default
VLAN is 1 and the port Port Native VLAN also is 1. The dual-mode feature supports untagged frames
on the default VLAN only. Thus, port 1/1 can send and receive untagged BPDUs for VLAN 1 and can
send and receive tagged BPDUs for the other VLANs.
Port 1/1 will process BPDUs as follows:
• Process IEEE 802.1Q BPDUs for VLAN 1.
• Process tagged PVST BPDUs for VLANs 2, 3, and 4.
• Drop untagged PVST BPDUs for VLAN 1.
Untagged port using VLAN 2 as port native VLAN
The following figure shows an example in which a port Port Native VLAN is not VLAN 1. In this case,
VLAN 1 uses tagged frames and VLAN 2 uses untagged frames.
PVST+ configuration examples
FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide 321
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