Question: Interpreting show stp (1)
To analyze Spanning Tree for #CCNA, you need to think about the root switch, then the root ports on the non-root switches, and then designated ports. That analysis usually begins with the show spanning-tree command – a command that packs an incredible amount of meaning into its relatively short output. Mastering every tidbit of meaning from show spanning-tree is a great place to avoid mistakes and pick up points on the exam. Here’s a new practice question that gives you some exercise.
Question
Which answers show facts confirmed by the output from local switch SW4 about the root switch and the listed port G0/1?
SW4> show spanning-tree vlan 1 VLAN0001 Spanning tree enabled protocol rstp Root ID Priority 24577 Address fa16.3e9a.25be Cost 4 Port 2 (GigabitEthernet0/1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
- The local switch (SW4) is the root switch
- Some other switch is the root switch
- The output does not confirm whether the local switch (SW4) is the root switch or not
- Port G0/1 is a port on the root switch
- Port G0/1 is a port on the local switch (SW4)
- Port G0/1 is a port on some other switch that may or may not be the root switch
As usual, I’ll post the answer in just a few days. At that time, a link to the answer will appear towards the bottom of this page, just above where the comments begin.
It is B, since the cost is 4 we can say that the interface in a GIG interface !!
and the other in E, Because it is a local interface on the switch that is connected to the root with the cost of 4 !!
Aaron,
Thanks for weighing in!
For the rest… answers and my explanation is in the answers post, linked just under the post, and just above this comments section.
Cheers!
W
Choices:- A, and, E.
Reasons:- for, (A). Low bridge priority value.
(E). Path cost 4 is a GEthernet port cost. G0/1 is in fact a port from local switch to the root switch. This port listed in the output of show spanning tree, command, is in accordance with the network topology, of this question.