Please check my STP diagram. my understanding is correct.
some people says it is correct and some says it is not correct.
This should be correct unless I missed something:
The reason the port to SW6 from SW2 is chosen as the root port instead of the port to SW1 is a lower root path cost of 8 versus 25.
The reason the port to SW7 from SW3 is chosen as the root port instead of the port to SW2 is the root path cost ties at 10 so the lowest sender bridge ID is chosen of SW7.
All other port roles I have changed are just root to blocking because the bridge does not have the best root path cost for the segment to become designated.
Remember that the STP calculation goes in this order:
1) Lowest Root Bridge ID
2) Lowest Root Path Cost
3) Lowest Sender Bridge ID
4) Lowest Sender Port ID
5) Lowest Receiver Port ID
Hope this answers your question.
