Moxa Technologies 405A Switch User Manual


 
EDS-408A/405A Series User’s Manual Featured Functions
3-22
y Locate and then disable less efficient paths (i.e., paths that have a lower bandwidth).
y Enable 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.
If STP is enabled, it will detect duplicate paths and prevent, or block, one of them from forwarding
traffic. In the following example, STP determines that traffic from LAN segment 2 to LAN
segment 1 should flow through Bridges C and A as this path has a greater bandwidth and is
therefore more efficient.
What happens if a link failure is detected? As shown in next figure, the STP process reconfigures
the network so that traffic from LAN segment 2 flows through Bridge B.
Brid
g
e B
Brid
g
e C
LAN 1
LAN 2
LAN 3
Brid
g
e A
Brid
g
e B
Brid
g
e C
LAN 1
LAN 2
LAN 3
Brid
g
e A