Environmental simulation experiment
Experimental topology
Addressing experiment
Experimental Procedure
First of all switches stp protocol becomes ordinary stp. In S1, S2, S3, S4, respectively, enter the following command.
We need to choose the root switch S1, S2 is the root backup switch. Need to type commands to manually configure, if the default is the default root switch S4. BID is smaller, is selected as the root switch. After configured using the command dis stp view the switch BID. Of course, the command can be used here stp root primary configure the root switch, with the command stp root scondary configures the root backup switch.
The port is also very important in the election stp years. Root port selection is based on data transmission overhead required to determine the size, we have to look at the port selection on the S4.
You can see the default selection E0 / 0/2 as the root port of the switch status is forwarding state, because smaller after E0 / 0/2 port overhead costs. We can use the display stp interface command to view the cost of a port ethernet0 / 0/2.
We can try to increase the cost value S2 again after the check port status. We will port cost value E0 / 0/2 is changed to 2000. And then found E0 / 0/1 becomes a root port.
