cciefun ccie/sp fortiOS linux tcl/tk avalanche/reflector canada immi, visit

howto choose ROOT port or designated port?


A, Same Region

1. Lowest Root Bridge ID
2. Lowest Root Path Cost to Root Bridge
3. Lowest Sender Bridge ID
4. Lowest Sender Port ID

B, Different Region

1, Lowest Root Bridge ID
2, External pathcost
3, Regional Root ID
4, Internal Path Cost
5, Sender ID
6, Sender Port ID
7, Receiver Port ID






Test Case (Same Region):
1, L: Root for Instance 3, R: Root for instance 5, 0
default path cost, default bridge priority
Block: 3=>RF1 5=>LF1 0=>LF1
WHY: Lowest Sender Bridge ID. HP had lower MAC address than BridgeL.

2, Move 5 and 0's block point from LF1 to A1
By: Reduce the bridge L's priority.
WHY: Lowest Sender Bridge ID. Bridge L has lower priority.

3, Move 5 and 0's block point from A1 to LF1
By: Increase the path cost of LS1