While reviewing an existing network design, you are discussing the characteristics of different STP versions.
Which protocol minimizes unicast flooding during TCN in a Layer 2 switched network with many VLANs?
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A. B. C. D.D.
The protocol that minimizes unicast flooding during TCN (Topology Change Notification) in a Layer 2 switched network with many VLANs is PVRSTP (Per-VLAN Rapid Spanning Tree Protocol).
Spanning Tree Protocol (STP) is used to prevent loops in a Layer 2 switched network by disabling redundant paths. When a topology change occurs, such as a link failure, STP needs to recalculate the path and send TCN messages to all switches in the network. During this process, all switches flood unicast traffic until the new path is determined. This can result in significant network congestion and performance issues, especially in networks with many VLANs.
MST (Multiple Spanning Tree) and PVSTP+ (Per-VLAN Spanning Tree Protocol Plus) both improve upon STP by allowing for multiple spanning trees and per-VLAN spanning trees, respectively. However, they still suffer from the same unicast flooding issue during TCN.
PVRSTP, on the other hand, is a rapid convergence protocol that only sends TCN messages on the VLAN where the topology change occurred. This reduces the impact of TCN on the network and minimizes unicast flooding. PVRSTP achieves this by maintaining a separate spanning tree for each VLAN, allowing for faster convergence and reducing the impact of topology changes on other VLANs.
In summary, the correct answer is C. PVRSTP minimizes unicast flooding during TCN in a Layer 2 switched network with many VLANs by maintaining separate spanning trees for each VLAN and only sending TCN messages on the affected VLAN.