What Does STP Mean in 200-301?
Full form: Spanning Tree Protocol
Also known as: Spanning Tree Protocol, IEEE 802.1D
Quick Definition
A Layer 2 loop-prevention protocol that blocks redundant paths in a switched network.
Full Definition
STP (IEEE 802.1D) prevents switching loops in networks with redundant links by placing some ports in a blocking state. STP elects a Root Bridge (the switch with the lowest Bridge ID), then each non-root switch selects a Root Port (best path to the Root Bridge) and each network segment elects a Designated Port. All other ports are placed in a blocking state. STP convergence can take 30–50 seconds with default timers.
CLI Command
show spanning-tree show spanning-tree vlan 10
Exam Trap — Don't Get Fooled
Lower Bridge Priority wins the Root Bridge election (default priority is 32768, VLAN ID is added). If priorities are equal, the switch with the lowest MAC address wins. Without configuration, the switch with the lowest MAC becomes root — this is usually not optimal.
Related 200-301 Terms
An enhanced version of STP that converges in seconds instead of 30–50 seconds.
A Cisco enhancement of STP that runs a separate spanning tree instance for each VLAN.
The STP control frames that switches exchange to elect the Root Bridge and maintain the spanning tree.
An STP feature that bypasses the Listening and Learning states on access ports, putting them immediately into Forwarding.
Shuts down a PortFast-enabled port if it receives a BPDU, protecting the spanning tree.
Prevents a port from becoming the Root Port, protecting the Root Bridge position.
Frequently Asked Questions
What does STP mean on the 200-301 exam?
STP (IEEE 802.1D) prevents switching loops in networks with redundant links by placing some ports in a blocking state. STP elects a Root Bridge (the switch with the lowest Bridge ID), then each non-root switch selects a Root Port (best path to the Root Bridge) and each network segment elects a Designated Port. All other ports are placed in a blocking state. STP convergence can take 30–50 seconds with default timers.
How does STP appear as a trap on the 200-301?
Lower Bridge Priority wins the Root Bridge election (default priority is 32768, VLAN ID is added). If priorities are equal, the switch with the lowest MAC address wins. Without configuration, the switch with the lowest MAC becomes root — this is usually not optimal.
How important is STP on the 200-301 exam?
STP falls under the Spanning Tree domain of the 200-301 exam. Understanding it in context with related terms like rstp and pvst-plus is essential for answering scenario-based questions correctly.