Reference Guide

bpduguard, although the interface is placed in an Error Disabled state when receiving the BPDU, the physical
interface remains up and spanning-tree drops packets in the hardware after a BPDU violation. BPDUs are dropped in
the software after receiving the BPDU violation.
This feature is the same as PortFast mode in spanning tree.
CAUTION: Configure EdgePort only on links connecting to an end station. EdgePort can cause loops if you enable it
on an interface connected to a network.
To enable EdgePort on an interface, use the following command.
• Enable EdgePort on an interface.
INTERFACE mode
spanning-tree pvst edge-port [bpduguard | shutdown-on-violation]
The EdgePort status of each interface is given in the output of the show spanning-tree pvst command, as
previously shown.
FTOS Behavior: Regarding the bpduguard shutdown-on-violation command behavior:
• If the interface to be shut down is a port channel, all the member ports are disabled in the hardware.
• When you add a physical port to a port channel already in an Error Disable state, the new member port is also
disabled in the hardware.
• When you remove a physical port from a port channel in an Error Disable state, the Error Disabled state is
cleared on this physical port (the physical port is enabled in the hardware).
• The reset linecard command does not clear the Error Disabled state of the port or the hardware Disabled
state. The interface continues to be disables in the hardware.
• You can clear the Error Disabled state with any of the following methods:
– Perform a shutdown command on the interface.
– Disable the shutdown-on-violation command on the interface (the no spanning-tree
stp-id portfast [bpduguard | [shutdown-on-violation]]
command).
– Disable spanning tree on the interface (the no spanning-tree command in INTERFACE mode).
– Disabling global spanning tree (the no spanning-tree command in CONFIGURATION mode).
PVST+ in Multi-Vendor Networks
Some non-Dell Networking systems which have hybrid ports participating in PVST+ transmit two kinds of BPDUs: an
802.1D BPDU and an untagged PVST+ BPDU.
Dell Networking systems do not expect PVST+ BPDU (tagged or untagged) on an untagged port. If this situation occurs,
FTOS places the port in an Error-Disable state. This behavior might result in the network not converging. To prevent
FTOS from executing this action, use the no spanning-tree pvst err-disable cause invalid-pvst-
bpdu command. After you configure this command, if the port receives a PVST+ BPDU, the BPDU is dropped and the
port remains operational.
Enabling PVST+ Extend System ID
In the following example, ports P1 and P2 are untagged members of different VLANs. These ports are untagged because
the hub is VLAN unaware. There is no data loop in this scenario; however, you can employ PVST+ to avoid potential
misconfigurations.
If you enable PVST+ on the Dell Networking switch in this network, P1 and P2 receive BPDUs from each other.
Ordinarily, the Bridge ID in the frame matches the Root ID, a loop is detected, and the rules of convergence require that
P2 move to blocking state because it has the lowest port ID.
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