When VTP pruning is enabled, what happens to VLAN traffic on trunk links where that VLAN is absent?

When VTP pruning is enabled, it specifically optimizes the flow of VLAN traffic by limiting it to only those trunk links where the VLAN is active. This means that if a VLAN is not present on a specific trunk link, the switch will withhold forwarding traffic for that VLAN across those links.

By doing so, VTP pruning enhances network efficiency by preventing unnecessary traffic from being transmitted where it is not needed, which reduces bandwidth consumption and minimizes the potential for broadcast storm conditions. This behavior ensures that resources are more effectively allocated by only sending VLAN traffic to switches that have active memberships for the VLAN in question.

The other options reflect misconceptions about the function of VTP pruning. For example, the notion that traffic is sent as usual does not account for the optimization VTP pruning provides, while completely blocking traffic could lead to issues in VLAN communication. Similarly, flooding traffic across all trunk links contradicts the goal of optimizing the network's efficiency and can lead to congestion and wasted bandwidth.