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Lab 04Packet Tracer Challenge
Observe STP Topology Changes
Redundancy & STP
Goal
Build a redundant switched network, observe stable STP state, and watch STP react when links fail and recover.
STPRSTPRedundancyPacket TracerFailover
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Observe STP Topology Changes
Build a redundant switched network, observe stable STP state, and watch STP react when links fail and recover.
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Redundancy & STP
Expected Topology
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2 or 3 switches with redundant links forming a loop (e.g., S1-S2, S2-S3, S1-S3), with PCs on access ports.
Step-by-Step
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1) Cable the redundant topology exactly (do not skip the extra link — it creates the loop STP must break). 2) Power on switches (STP runs by default in PT). 3) Observe the stable state: show spanning-tree, identify root bridge, root port (RP), designated ports and the single blocking port. 4) Fail a link: shutdown the port carrying the active path (interface g0/2 + shutdown); the blocked port should transition to Forwarding; note reconvergence time (RSTP ~sub-second to a few seconds; classic STP ~30-50s). 5) Restore the link (no shutdown) and observe roles return. 6) If required, observe TCNs via show spanning-tree counters or debug spanning-tree events.
R1#
show spanning-tree
show spanning-tree vlan 1
show spanning-tree summaryWhat the Grader Checks