STP Troubleshooting STP 2

Question 1

How do you configure STP priority for load balancing across VLANs?

Accepted Answer

Set different root bridges for different VLANs using per-VLAN priority values

Answer

By making different switches the root bridge for different VLANs, traffic can be distributed across redundant links.

Question 2

What is the TCN BPDU?

Accepted Answer

Topology Change Notification sent by a switch when it detects a port state change

Answer

TCN BPDUs notify the root bridge of topology changes so the network can update its forwarding tables.

Question 3

How does STP interact with EtherChannel?

Accepted Answer

STP treats an EtherChannel as a single logical link, preventing it from blocking individual member ports

Answer

EtherChannel bundles physical links into one logical link, so STP sees a single high-bandwidth connection rather than redundant links.

Question 4

What is the recommended STP configuration for access layer ports?

Accepted Answer

Enable PortFast and BPDU guard on all access ports connected to end devices

Answer

PortFast provides immediate connectivity while BPDU guard protects against unauthorized switches being connected.

Question 5

What debugging tools are available for STP issues?

Accepted Answer

debug spanning-tree events, show spanning-tree detail, show spanning-tree interface

Answer

Multiple show and debug commands provide visibility into STP operations, state changes, and BPDU processing.

(STP) Spanning Tree Protocol Practice Test