STP Practice Test PDF (Free Printable 2026 June)

STP Practice Test PDF – Free Printable Spanning Tree Protocol Exam Prep

Preparing for networking certification exams covering Spanning Tree Protocol (STP)? A printable STP practice test PDF gives you an offline format to review STP operation, RSTP, port states, root bridge election, and STP troubleshooting — topics that appear on CCNA, CompTIA Network+, and other network engineering certification exams. Working through STP questions on paper helps cement the logical reasoning and election process calculations that network certification exams test. This page provides a free PDF download and a comprehensive STP exam preparation guide.

Spanning Tree Protocol (IEEE 802.1D) is a Layer 2 protocol that prevents switching loops in Ethernet networks with redundant paths. STP and its faster successor RSTP (Rapid Spanning Tree Protocol, IEEE 802.1w) are core networking fundamentals tested on virtually every network certification from CompTIA Network+ through CCIE.

STP Core Concepts for Certification Exams

STP certification questions test a consistent set of concepts regardless of which exam you're taking. Your STP practice test PDF covers all major exam topics.

Root Bridge Election

Every STP domain elects one root bridge — the switch with the lowest Bridge ID wins. Bridge ID = Bridge Priority (2 bytes) + MAC address (6 bytes). Default priority is 32768 (configurable in multiples of 4096). When priorities are equal, the switch with the lowest MAC address becomes root. In practice, you should manually configure the root bridge using spanning-tree vlan X priority 0 or spanning-tree vlan X root primary — relying on automatic election in production networks is a misconfiguration risk. Root bridge election questions often give you bridge priorities and MACs and ask which switch becomes root.

STP Port States and Roles

Port Roles determine a port's function in the spanning tree: Root Port (RP) — the port with the best path cost to the root bridge (one per non-root switch); Designated Port (DP) — the port forwarding traffic toward the root bridge on each network segment (one per segment); Non-Designated Port — blocked to prevent loops. Port States in 802.1D are: Blocking (receives BPDUs, no traffic forwarding), Listening (15 sec — sends/receives BPDUs, no MAC learning), Learning (15 sec — populates MAC table, no user traffic), Forwarding (normal operation). RSTP simplifies to: Discarding, Learning, and Forwarding.

Path Cost Calculation

STP determines the best path to the root bridge using path cost. Standard IEEE costs: 10 Mbps = 100, 100 Mbps = 19, 1 Gbps = 4, 10 Gbps = 2. The Root Port on each switch is the port with the lowest cumulative path cost to the root bridge. When path costs are equal, the tiebreaker is lowest sender Bridge ID, then lowest port ID. Certification questions often ask which port becomes the Root Port given a topology diagram with specified interface speeds.

RSTP Enhancements

RSTP (802.1w) significantly improves convergence. Key RSTP concepts: new port roles — Alternate Port (backup to root port, immediately transitions to forwarding if RP fails), Backup Port (redundant DP on same segment); Edge Ports (equivalent to PortFast — immediately transition to forwarding for end-device connections); RSTP uses proposal/agreement handshake instead of timer-based transitions, enabling convergence in 1-6 seconds vs. 30-50 seconds for 802.1D.

Cisco STP Variants

Cisco-specific STP content is tested on CCNA and CCNP: PVST+ (Per-VLAN Spanning Tree Plus — one STP instance per VLAN, allows load balancing across VLANs by making different switches root for different VLANs), Rapid PVST+ (RSTP convergence with per-VLAN instances), and MST (Multiple Spanning Tree — maps multiple VLANs to fewer STP instances, more scalable). PortFast (immediately transitions access ports to forwarding, bypasses STP states — only use on end-device ports), BPDU Guard (shuts down a PortFast port if it receives a BPDU — prevents rogue switches), and Root Guard (prevents a port from becoming root port — protects root bridge placement) are common exam topics.

How to Use This PDF

Practice root bridge election calculations with different priority/MAC combinations. After this PDF, take online STP practice tests at stp for instant scored feedback by STP concept area.

Free STP Practice Tests Online

After completing this PDF, take full online STP practice tests at stp — instant scoring across root bridge election, port states, path cost, RSTP, and Cisco-specific STP features with explanations for every answer. STP is tested on CCNA, Network+, and CCNP — use both the PDF and online practice to build the systematic STP analysis skills these exams require.