trunk.
Table 7. RSTP Auto Port Trunk Costs
Port Speed | Port Cost |
|
|
|
|
10 Mbps | 20,000 |
|
|
100 Mbps | 20,000 |
|
|
1000 Mbps | 2,000 |
|
|
You cannot set the port cost manually.
Port Priority
If two paths have the same port cost, the bridges must select a preferred path. In some instances this can involve the use of the port priority parameter. This parameter is used as a tie breaker when two paths have the same cost.
The range for port priority is 0 to 240. As with bridge priority, this range is broken into increments, in this case multiples of 16. Table 8 lists the valid port priority values. The default value is 128, which is increment 8.
Table 8. Port Priority Value Increments
Increment | Port |
| Increment | Port |
Priority |
| Priority | ||
|
|
| ||
|
|
|
|
|
|
|
|
|
|
0 | 0 |
| 8 | 128 |
|
|
|
|
|
1 | 16 |
| 9 | 144 |
|
|
|
|
|
2 | 32 |
| 10 | 160 |
|
|
|
|
|
3 | 48 |
| 11 | 176 |
|
|
|
|
|
4 | 64 |
| 12 | 192 |
|
|
|
|
|
5 | 80 |
| 13 | 208 |
|
|
|
|
|
6 | 96 |
| 14 | 224 |
|
|
|
|
|
7 | 112 |
| 15 | 240 |
|
|
|
|
|
Forwarding Delay and Topology Changes
If there is a change in the network topology due to a failure, removal, or addition of any active components, the active topology also changes. This may trigger a change in the state of some blocked ports. However, a change in a port state is not activated immediately.
It might take time for the root bridge to notify all bridges that a topology
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