nerdexam
Cisco

200-301 · Question #325

When using Rapid PVST+, which command guarantees the switch is always the root bridge for VLAN 200?

The correct answer is C. spanning -tree vlan 200 priority 0. To guarantee a switch is always the root bridge for VLAN 200 in Rapid PVST+, set its spanning-tree priority for that VLAN to 0.

Submitted by priya_blr· Mar 5, 20262.0 Network Access

Question

When using Rapid PVST+, which command guarantees the switch is always the root bridge for VLAN 200?

Options

  • Aspanning -tree vlan 200 priority 614440
  • Bspanning -tree vlan 200 priority 38572422
  • Cspanning -tree vlan 200 priority 0
  • Dspanning -tree vlan 200 root primary

How the community answered

(47 responses)
  • A
    4% (2)
  • B
    13% (6)
  • C
    74% (35)
  • D
    9% (4)

Why each option

To guarantee a switch is always the root bridge for VLAN 200 in Rapid PVST+, set its spanning-tree priority for that VLAN to `0`.

Aspanning -tree vlan 200 priority 614440

`614440` is not a valid STP priority value; priorities must be multiples of 4096 and range from 0 to 61440.

Bspanning -tree vlan 200 priority 38572422

`38572422` is not a valid STP priority value; priorities must be multiples of 4096 and range from 0 to 61440.

Cspanning -tree vlan 200 priority 0Correct

In Spanning Tree Protocol, the root bridge is elected based on the lowest bridge ID. Setting the `spanning-tree vlan 200 priority` to `0` assigns the lowest possible bridge priority, ensuring the switch will be chosen as the root bridge for VLAN 200.

Dspanning -tree vlan 200 root primary

The `spanning-tree vlan 200 root primary` command sets the priority to `24576` (or `28672` in certain conditions), which makes the switch likely to be the root, but it does not guarantee it if another switch has a lower priority (e.g., 0).

Concept tested: STP root bridge priority configuration

Source: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12_2_55_se/configuration/guide/scg/sw_stp.html#wp1077673

Topics

#Rapid PVST+#STP root bridge election#VLAN STP#Cisco CLI

Community Discussion

No community discussion yet for this question.

Full 200-301 Practice