Moxa Technologies EDS-726 user manual What is STP?

EDS-726 Series User’s Manual Featured Functions

What is STP?

STP (802.1D) is a bridge-based system that is used to implement parallel paths for network traffic. STP uses a loop-detection process to:

yLocate and then disable less efficient paths (i.e., paths that have a lower bandwidth).

yEnable one of the less efficient paths if the most efficient path fails.

The figure below shows a network made up of three LANs separated by three bridges. Each segment uses at most two paths to communicate with the other segments. Since this configuration can give rise to loops, the network will overload if STP is NOT enabled.

Bridge A

LAN 1

Bridge B

LAN 2

Bridge C

LAN 3

If STP is enabled, it will detect duplicate paths and prevent, or block, one of them from forwarding traffic. In the following example, STP determined that traffic from LAN segment 2 to LAN segment 1 should flow through Bridges C and A because this path has a greater bandwidth and is therefore more efficient.

Bridge A

LAN 1

Bridge B

LAN 2

Bridge C

LAN 3

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