PortFast: A Cisco feature that allows switch ports connected to end devices (e.g., PCs, servers) to skip Spanning Tree Protocol (STP) Listening and Learning states, moving directly to Forwarding. This reduces convergence time from ~30-50 seconds to nearly instant, ideal for access ports. However, enabling PortFast on switch-to-switch links risks loops.

PortFast BPDU Guard Enhances security by shutting down (error-disabling) a PortFast-enabled port if it receives a BPDU, indicating an unauthorized switch connection. It protects against loops caused by misconfigurations or rogue devices. Configured globally or per interface, it’s disabled by default.[]

Key Difference: PortFast accelerates convergence for end devices; BPDU Guard ensures these ports remain secure by disabling them upon receiving unexpected BPDUs, preventing network disruptions.

OEM Terminology Variations
Cisco Uses “PortFast” and “BPDU Guard” as standard terms. Commands like spanning-tree portfast and spanning-tree portfast bpduguard apply.

-Arista Refers to PortFast as “edge-port” and supports BPDU Guard/Filter with commands like spanning-tree edge-port bpduguard.
Juniper Calls it “edge mode” for PortFast-like functionality and “BPDU protection” for Guard-like features.
HP/Aruba Uses “edge-port” for PortFast and “BPDU protection” for Guard, with slight configuration differences.
Other OEMs May use terms like “fast-start” or “port-immediate” for PortFast, and “BPDU block” for Guard, but functionality aligns with Cisco’s model.

Best Practice: Enable PortFast only on edge ports and pair with BPDU Guard to ensure stability and security.