Understanding Rapid PVST+
• Forwards frames received from the attached segment.
• Forwards frames switched from another port for forwarding.
• Incorporates the end station location information into its address database.
• Receives BPDUs and directs them to the system module.
• Processes BPDUs received from the system module.
• Receives and responds to network management messages.
Disabled State
A LAN port in the disabled state does not participate in frame forwarding or STP. A LAN port in the disabled
state is virtually nonoperational.
A disabled LAN port performs as follows:
• Discards frames received from the attached segment.
• Discards frames switched from another port for forwarding.
• Does not incorporate the end station location into its address database. (There is no learning, so there is
no address database update.)
• Does not receive BPDUs from neighbors.
• Does not receive BPDUs for transmission from the system module.
Summary of Port States
The following table lists the possible operational and Rapid PVST+ states for ports and the corresponding
inclusion in the active topology.
Table 5: Port State Active Topology
Operational Status
Enabled
Enabled
Enabled
Disabled
Synchronization of Port Roles
When the switch receives a proposal message on one of its ports and that port is selected as the new root port,
Rapid PVST+ forces all other ports to synchronize with the new root information.
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
64
Port State
Blocking
Learning
Forwarding
Disabled
Configuring Rapid PVST+
Is Port Included in the Active
Topology?
No
Yes
Yes
No
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