CCNA 200-301 v1.1 reference — Network Access
Rapid PVST+
Root bridge election, port roles and states, path cost and tie-breaking, and how Rapid PVST+ converges faster than classic STP.
Objective 2.5v1.1 exam target
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Election sequence
- Every switch advertises its Bridge ID: priority (lower wins; default 32768) + system ID extension (VLAN) + MAC (tiebreak).
- The lowest BID becomes the root bridge for that VLAN.
- Each non-root switch picks its root port — the port with the lowest cost path to the root.
- Each segment picks one designated port (the port advertising the best path); everything else becomes alternate/backup and discards.
RSTP port roles and states
| Role | State | Meaning |
|---|---|---|
| Root port | Forwarding | Best path to the root on each non-root switch |
| Designated port | Forwarding | Best port for a segment — forwards for that link |
| Alternate port | Discarding | Backup path to the root (blocked) |
| Backup port | Discarding | Backup for a designated port on a shared segment |
STP/RSTP timers and parameters
| Parameter | Classic STP (802.1D) | Rapid PVST+ (802.1w) |
|---|---|---|
| Hello interval | 2 s | 2 s |
| Max age | 20 s | 3 missed hellos (~6 s) triggers reconvergence |
| Learning states | Listening 15 s + Learning 15 s | Discarding → learning → forwarding, often sub-second with edge ports |
| Convergence | ~30–50 s | Sub-second on point-to-point links via proposal/agreement |
| Port cost (default) | Bandwidth-derived (e.g., 1G = 4) | Same cost model |
Defaults are per standard and Cisco implementation; verify platform docs for exact values.
$ show spanning-tree vlan 10 (interpreted)
VLAN0010 Root ID Priority 32778 Address 00aa.bb01.0201Root's BID — priority 32768+VLAN10. Root port Fa0/1Non-root switch: its best path to the root leaves Fa0/1.Gi1/0/1 Desg FWD 4 128.1 P2pDesignated port forwarding, cost 4, point-to-point link.Gi1/0/2 Root FWD 4 128.2 P2pRoot port — best path toward the root.Gi1/0/3 Altn BLK 4 128.3 P2pAlternate port blocked — your redundant path.Related resources
Sources
- Cisco CCNA 200-301 v1.1 Exam Topics (official PDF) — reviewed 2026-11-02
- IEEE 802.1 Working Group (802.1Q/802.1w) — reviewed 2026-11-02
- Cisco — LAN Switching Command Reference — reviewed 2026-11-02
Targets CCNA 200-301 v1.1 objectives. Supplemental blocks are labeled beyond exam scope.