# Changing the STP Settings:

#### There are 2 tools available to change the [STP ](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/stp-spanning-tree-protocol)Settings:

1. Configure BID
2. Configure STP Port costs

### Configure BID:

* BID consists of Bridge Priority + MAC Address. We cannot configure MAC Address as it is a burned in MAC Address. Hence we can change the priority of a Switch.
* Default Priority is 32768&#x20;
* Admin can reduce the Priority to make that Switch a Root Bridge.

### Configure STP Port costs:

* Default Port Costs:

| Ethernet Speed | IEEE Cost: (1998 & Before) Short Path Cost Method Port Cost | IEEE Cost: (2004 & After) Long Path Cost Method Port Cost |
| -------------- | ----------------------------------------------------------- | --------------------------------------------------------- |
| 10 Mbps        | 100                                                         | 2,000,000 (2 Million)                                     |
| 100 Mbps       | 19                                                          | 200,000 (2 Hundred Thousand)                              |
| 1 Gbps         | 4                                                           | 20,000                                                    |
| 10 Gbps        | 2                                                           | 2000                                                      |
| 100 Gbps       | N/A                                                         | 200                                                       |
| 1 Tbps         | N/A                                                         | 20                                                        |

* Reduce the port cost to favor the link & increase the port cost to avoid the link.
* You can change the Short/Long port cost by using (#spanning-tree pathcost method (short/long)) command.

## Reference:

* CCNA 200-301 OCG, Volume 1, Pg. 223-224- Wendell Odom.
