spanning tree algorithm - technical definition

An algorithm used in transparent bridges that dynamically determines the best path from source to destination. It avoids bridge loops (two or more paths linking one segment to another), which can cause the bridges to misinterpret results.

The algorithm creates a hierarchical "tree" that "spans" the entire network including all switches. It determines all redundant paths and makes only one of them active at any given time. The spanning tree protocol (STP) is part of the IEEE 802.1 standard. See BPDU.