Home » Cisco » 200-125 » Which option describes how a switch in rapid PVST+ mode responds to a topology change?
Which option describes how a switch in rapid PVST+ mode responds to a topology change?
A. It immediately deletes dynamic MAC addresses that were learned by all ports on the switch.
B. It sets a timer to delete all MAC addresses that were learned dynamically by ports in the same
STP instance.
C. It sets a timer to delete dynamic MAC addresses that were learned by all ports on the switch.
D. It immediately deletes all MAC addresses that were learned dynamically by ports in the same
STP instance.
Answer: D
Explanation:
Rapid PVST+This spanning-tree mode is the same as PVST+ except that is uses a rapid convergence based on the IEEE 802.1w standard. To provide rapid convergence, the rapid PVST+ immediately deletes dynamically learned MAC address entries on a per-port basis upon receiving a topology change. By contrast, PVST+ uses a short aging time for dynamically learned MAC address entries.
The rapid PVST+ uses the same configuration as PVST+ (except where noted), and the switch needs only minimal extra configuration. The benefit of rapid PVST+ is that you can migrate a large PVST+ install base to rapid PVST+ without having to learn the complexities of the MSTP configuration and without having to reprovision your network. In rapid-PVST+ mode, each VLAN runs its own spanning-tree instance up to the maximum supported.
|
FULL Printable PDF and Software. VALID exam to help you pass.
|
 |
I think the answer is B
Rapid doesn’t set timers to reduce delay when it detects a topology change immediately . Pvst as the regular STP does wait for the timer to run out
“The topology change notification floods quickly across the entire topology. The system flushes dynamic
entries immediately on a per-port basis wh
en it receives a topology change. ”
Source:http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/CLIConfigurationGuide/RPVSpanningTree.pdf