LAN Switch Forwarding Logic
STP limits where a switch chooses to forward frames, for the purpose of preventing problems with loops. These problems happen because, in some cases, the core LAN switch logic would literally forward a frame around the LAN forever without some external method like STP to prevent it. So, to understand STP, you need a good recall of the core logic of a LAN switch, particularly the switch forwarding logic. Then you can understand why frames would loop without STP, and then how STP prevents the loop.
The following list details all the steps in how a LAN switch forwards a frame, while ignoring the role of STP.
Step 1.
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