Brocade TurboIron 24X Series Configuration Guide - Manual (Page 605)

Brocade TurboIron 24X Series Configuration Guide 571
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PVST/PVST+ compatibility
Configuring PVST+ support
PVST+ support is automatically enabled when the port receives a PVST BPDU. You can manually
enable the support at any time or disable the support if desired.
If you want a tagged port to also support IEEE 802.1Q BPDUs, you need to enable the dual-mode
feature on the port. The dual-mode feature is disabled by default and must be enabled manually.
A port that is in PVST+ compatibility mode due to auto-detection reverts to the default MSTP mode
when one of the following events occurs:
• The link is disconnected or broken
• The link is administratively disabled
• The link is disabled by interaction with the link-keepalive protocol
This allows a port that was originally interoperating with PVST+ to revert to MSTP when connected
to a device.
Enabling PVST+ support manually
To immediately enable PVST+ support on a port, enter commands such as the following.
TurboIron(config)#interface ethernet 1
TurboIron(config-if-1)#pvst-mode
Syntax: [no] pvst-mode
NOTE
If you disable PVST+ support, the software still automatically enables PVST+ support if the port
receives a BPDU with PVST+ format.
NOTE
If 802.1W and pvst-mode (either by auto-detection or by explicit configuration) are enabled on a
tagged VLAN port, 802.1W will treat the PVST BPDUs as legacy 802.1D BPDUs.
Enabling dual-mode support
To enable the dual-mode feature on a port, enter the following command at the interface
configuration level for the port.
TurboIron(config-if-1)#dual-mode
Syntax: [no] dual-mode [<vlan-id>]
The <vlan-id> specifies the port Port Native VLAN. This is the VLAN on which the port will support
untagged frames. By default, the Port Native VLAN is the same as the default VLAN (which is VLAN
1 by default).
For more information about the dual-mode feature, refer to “Dual-mode VLAN ports” on page 415.
Displaying PVST+ support information
To display PVST+ information for ports on a device, enter the following command at any level of the
CLI.