Siemens S223 User Manual
User Manual UMN:CLI
SURPASS hiD 6615 S223/S323 R1.5
SURPASS hiD 6615 S223/S323 R1.5
A50010-Y3-C150-2-7619 225
8.3.10 Sample
Configuration
Backup Route
When you design layer 2 network, you must consider backup route for stable STP net-
work. This is to prevent network corruption when just one additional path exits.
work. This is to prevent network corruption when just one additional path exits.
Switch A
Switch B
Switch E
Switch C
Switch D
Aggregation
Switch
Broken
PC-A
Fig. 8.26
Example of Layer 2 Network Design in RSTP Environment
In ordinary case, data packets go to Root switch A through the blue path. The black ar-
rows describe the routine path to the Aggregation Switch. And the dot lines are in blocking
state. But if there is a broken between Switch A and Switch B, the data from PC-A should
find another route at Switch D. Switch D can send the data to Switch C and Switch E. Be-
cause Switch E has shorter hop count than Switch B, the data may go through the Switch
E and A as the red line. And we can assume Switch E is also failed at the same time. In
this case, since Switch D can has the other route to Switch C, the network can be stable
than just one backup route network.
rows describe the routine path to the Aggregation Switch. And the dot lines are in blocking
state. But if there is a broken between Switch A and Switch B, the data from PC-A should
find another route at Switch D. Switch D can send the data to Switch C and Switch E. Be-
cause Switch E has shorter hop count than Switch B, the data may go through the Switch
E and A as the red line. And we can assume Switch E is also failed at the same time. In
this case, since Switch D can has the other route to Switch C, the network can be stable
than just one backup route network.