User's Manual

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CIST
CIST stands for Common and Internal Spanning Tree. Common and Internal Spanning Tree (CIST) means the
spanning tree comprised by allsingle switches and interconnected LAN. These switches may belong to different
MSTregions. They may be switches running traditional STP or RSTP. Switches running STP or RSTP in the
MST regions are considered to be in their own regions.
After the network topology is stable, the whole CIST chooses a CIST root bridge. An internal CIST root bridge
will be selected in each region, which is the shortest path from the heart of the region to CIST root.