多项选择题

A. Upgrade Spanning Tree Protocol to Rapid Spanning Tree Protocol.
B. Change Business VLAN PCs to switch 1 and switch 4.
C. Force the root bridge to be switch 2, instead.
D. Adjust spanning-tree timers (max-age and forward-delay).
E. Shut down all unused ports.
F. Use MSTP to separate the Engineering VLAN from the Business VLAN to optimize spanning-tree convergence time within each VLAN