Reference Guide

728 | Per-VLAN Spanning Tree Plus (PVST+)
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Related
Commands
spanning-tree pvst err-disable
z
Place ports in an err-disabled state if they receive a PVST+ BPDU when they are members an untagged
VLAN.
Syntax
spanning-tree pvst err-disable cause invalid-pvst-bpdu
Defaults
Enabled; ports are placed in err-disabled state if they receive a PVST+ BPDU when they are members
of an untagged VLAN.
Command Modes
INTERFACE
Command
History
Usage
Information
Some non-Dell Networking systems which have hybrid ports participating in PVST+ transmit two
kinds of BPDUs: an 802.1w BPDU and an untagged PVST+ BPDU.
Dell Networking systems do not expect PVST+ BPDU on an untagged port. If this happens, FTOS
places the port in error-disable state. This behavior might result in the network not converging. To
prevent FTOS from executing this action, use the command no spanning-tree pvst err-disable cause
invalid-pvst-bpdu.
Related
Commands
tc-flush-standard
z
Enable the MAC address flushing upon receiving every topology change notification.
Syntax
tc-flush-standard
To disable, use the no tc-flush-standard command.
Defaults
Disabled
Command Modes
CONFIGURATION
Command
History
Usage
Information
By default FTOS implements an optimized flush mechanism for PVST+. This helps in flushing the
MAC addresses only when necessary (and less often) allowing for faster convergence during topology
changes. However, if a standards-based flush mechanism is needed, this knob command can be turned
on to enable flushing MAC addresses upon receiving every topology change notification.
show spanning-tree pvst View PVST+ configuration
S6000
Version 9.0.2.0 Introduced on the S6000.
Version 8.3.11.1 Introduced on Z9000.
show spanning-tree pvst View the PVST+ configuration.
S6000
Version 9.0.2.0 Introduced on the S6000.
Version 8.3.11.1 Introduced on Z9000.