If a new root election occurs and SW2 becomes the root, what happens to interfaces in a forwarding state before the change?

When a new root bridge is elected in a Spanning Tree Protocol (STP) scenario, the key aspect to understand is that the interfaces associated with the former root bridge and designated ports typically remain in a forwarding state if they are still the best path to the root bridge after the election.

If SW2 becomes the new root, the paths to this new root are recalculated, but the interfaces that were previously in a forwarding state will remain so, provided that the topology does not change in a way that affects their connectivity to the new root. The STP algorithm only changes port states when it needs to reconfigure the network to prevent loops.

The switch will evaluate the spanning tree topology and ports, but unless there’s a specific loop or a need to reblock paths to the new root, the interfaces that were already forwarding will continue to do so. It's important to note that STP dynamically maintains a stable forwarding state as much as possible when a new root bridge is elected, hence the interfaces do not automatically transition to a blocking or listening state without a specific reason justifying such a change in state.

Thus, the understanding is rooted in how STP manages the state of the ports relative to the root bridge, ensuring minimal disruption and