Deceptive Speed: How to Fix Fast, Unstable Wi-Fi
0 likes324 views
The webinar 'Deceptive Speed: How to Fix Fast, Unstable Wi-Fi' presented by Ben Miller discusses the complexities of Wi-Fi throughput testing and how optimal settings can lead to less stability. Participants learned about various factors affecting Wi-Fi performance, including channel conditions, device dependency, and interference from neighbor devices. The session also introduced tools for analysis and emphasized the importance of broadening channel width and enabling features like band steering and airtime fairness for improved network stability.
Deceptive Speed: How to Fix Fast, Unstable Wi-Fi
- 2. Today’s Webinar: Deceptive Speed: How to Fix Fast, Unstable Wi-Fi • Presenter: Ben Miller, Wireless Specialist • Today’s webinar will be available on- demand following this live session. Simply use the same url you used today. Follow us @NETSCOUT
- 3. People Love Throughput Tests • Tech folks: ‘stress testing’ • Regular folks: “will my app work?” • Several methods – Apps – Speedtest – Web - Google
- 4. The problem with Wi-Fi throughput tests • Changes as channel conditions change • Device-dependent • Affected by non- Wi-Fi factors
- 5. But… Let’s say you want throughput • In Wi-Fi, higher throughput = less stability • Optimized throughput settings give you… – More crowded channels Wide channels = fewer channels = more device per channel – Higher SNR required – Less channels available (Band steering) 2.4 GHz channels unavailable to many devices – Less channel time in difficult areas (Airtime fairness)
- 6. If you still want high throughput… • Use wider channels – 40 MHz; maybe even 80 MHz • Enable DFS – Channels 52-144 • Use low AP Tx power • Enable band steering • Enable airtime fairness
- 7. Now… If you want stable Wi-Fi • Issues beyond the Wi-Fi • What affects Wi-Fi throughput? – How to analyze it • One… more… thing
- 8. • Each ‘leg’ is independent – Wi-Fi speed – Network speed – Internet speed Issues beyond Wi-Fi: ‘Data relay race’ Server Internet Network Wi-Fi
- 9. What affects Wi-Fi throughput? • Data rates • Number of frames • Retries • Neighbors
- 10. • High data rate = less required channel time ‒ For data and Layer 2, 3, 4 headers Data rates AP 1500 Bytes Near Far 1500 Bytes Near Far Timeline (173 Mbps) (39 Mbps) (quiet) (quiet)
- 11. Identifying data rates • Wi-Fi channel analyzer (a.k.a. Wi-Fi protocol analyzer) ‒ NETSCOUT AirMagnet WiFi Analyzer Included in NETSCOUT OptiView XG
- 12. Number of frames • Approx. 100 microseconds of collision avoidance • Approx. 40 microseconds per PHY header 1500 Bytes Near Near Timeline (173 Mbps) 1500 Bytes (173 Mbps) PHYCSMA/CA PHYCSMA/CA Drawn to scale; data includes SIFS and Ack (quiet) (quiet)
- 13. Identifying the number of frames • Wi-Fi channel analyzer
- 14. • Wasted channel time Retries 1500 Bytes Near Near Timeline (173 Mbps) 1500 Bytes (173 Mbps) PHYCSMA/CA PHYCSMA/CA Drawn to scale; data includes SIFS and Ack (quiet)
- 15. Cause of retries • Crowded channel • Interference
- 16. Identifying retries • Wi-Fi channel analyzer
- 17. Neighbors • Creates extra quiet time – Collision avoidance • Two ways neighbors cause issues – Lots of devices – Lots of Wi-Fi traffic
- 18. Identifying neighbor traffic • Wi-Fi channel analyzer
- 19. Identifying neighbor devices • Wi-Fi Scanner ‒ NETSCOUT AirCheck G2
- 20. There’s one… more… thing… • Auto test! • Tap once - let the AirCheck G2 do the rest ‒ (Field techs will thank you) • Summarizes everything
- 21. Questions? • Webinar: Deceptive Speed: How to Fix Fast, Unstable Wi-Fi – Presented by Ben Miller, Wireless Specialist AP
- 22. THANK YOU • Today’s webinar will be available on-demand immediately following today’s live session. Simply use the same url that you used today. enterprise.netscout.com