Quick Answer

The answer is 20 seconds for the Max Age timer. This default value is correct because the Spanning Tree Protocol (STP) uses the Max Age timer to determine how long a switch will wait after losing contact with the root bridge before recalculating the topology, and the IEEE 802.1D standard sets this at 20 seconds to ensure stability during network convergence. The Hello timer defaults to 2 seconds, which controls how often bridges send configuration BPDUs, while the Forward Delay timer defaults to 15 seconds, governing the listening and learning states before a port transitions to forwarding. On the ENCOR 350-401 exam, this drag-and-drop question tests your recall of these three default STP timer values, often appearing in the Layer 2 technologies section; a common trap is confusing Max Age with Forward Delay or forgetting that Hello is the shortest value. A reliable memory tip is to remember the sequence: Hello is 2 (like two hello waves), Forward Delay is 15 (half of 30), and Max Age is 20 (the oldest timer).