11.3. Spanning Tree Protocol (STP)

Once upon a time, a company called Digital Equipment Corporation (DEC) was purchased and renamed Compaq. But before that happened, DEC created the original version of Spanning Tree Protocol (STP). The IEEE later created its own version of STP called 802.1D. Yet again, it's not all clear skies—by default, most switches run the IEEE 802.1D version of STP, which isn't compatible with the DEC version. The good news is that there is a new industry standard called 802.1w, which is faster, but not enabled by default on any switches.

To begin with, STP's main task is to stop network loops from occurring on your Layer 2 network (bridges or switches). It achieves this feat by vigilantly monitoring the network to find ...

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