Cisco N5010P-N2K-BE, Software Configuration Manual

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S e n d f e e d b a c k t o n x 5 0 0 0 - d o c f e e d b a c k @ c i s c o . c o m
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Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01
Chapter 8 Configuring Rapid PVST+
Information About Rapid PVST+
Figure 8-5 Sample Topology Demonstrating Port Roles
Port States
This section describes the Rapid PVST+ and MST port states:
•
Rapid PVST+ Port State Overview, page 8-11
• Blocking State, page 8-12
•
Learning State, page 8-12
• Forwarding State, page 8-12
•
Disabled State, page 8-13
• Summary of Port States, page 8-13
Rapid PVST+ Port State Overview
Propagation delays can occur when protocol information passes through a switched LAN. As a result,
topology changes can take place at different times and at different places in a switched network. When
a LAN port transitions directly from nonparticipation in the spanning tree topology to the forwarding
state, it can create temporary data loops. Ports must wait for new topology information to propagate
through the switched LAN before starting to forward frames.
Each LAN port on a software using Rapid PVST+ or MST exists in one of the following four states:
•
Blocking—The LAN port does not participate in frame forwarding.
•
Learning—The LAN port prepares to participate in frame forwarding.
•
Forwarding—The LAN port forwards frames.
•
Disabled—The LAN port does not participate in STP and is not forwarding frames.
Bridge_ID=1
Root_ID =1
Bridge_ID=2
Root_ID =1
Bridge_ID=3
Root_ID =1
Bridge_ID=5
Root_ID =1 Bridge_ID=4
Root_ID =1 Bridge_ID=6
Root_ID =1 Bridge_ID=7
Root_ID =1
Alternate port
Backup port
Designated port
Root port
Active link
Blocked link
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