Does Packet Tracer 4.11 use the Spanning Tree Protocol?
Yes. Packet Tracer 4.11 models Per Vlan Spanning Tree Protocol to break possible switching loops. When first loading files with switches, or routers with switchports, the Spanning Tree Protocol will go through the different states on the ports before putting them in forwarding state, indicated by an amber light. If this causes an annoying delaying, toggling between Realtime and Simulation mode 3 or 4 times will decrease the delay caused by the transition of states.
