ARUBA community - WLAN design and troubleshooting
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Don't matter how many WLANs have you implemented and the installation guides that you read: AirHeads can always teach you something, and (only for Eng.) in a funny way. Real effective. Thanks Blake.
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ARUBA community - WLAN design and troubleshooting
- 1. ATMOSPHERE 2014 AIRHEADS@ Advanced RF Design & Troubleshooting Blake Krone June 2014
- 2. CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved 2 #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Agenda Who Am I? Past and Present Design Goals Design, Design, Design Love Thy Patch Demystifying RF With Tools
- 3. 3 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Who Am I?
- 4. 4 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Who Am I? Blake Krone blake.krone@nostringsattachedshow.com @blakekrone http://NSAShow.com All around tech junkie, programmer, RC junkie CWNA, CCIE #31229 (Wireless)
- 5. 5 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Past & Present Design Goals
- 6. 6 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Pre #GenMobile Design Goals Green = Good = Coverage • Designed for Coverage – Full bars, devices were connected • Large cells, high power • Less than 2 devices per person – Laptop – Smartphone
- 7. 7 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ #GenMobile Design Goals Green = Good = Coverage – no longer applicable! • Designed for Capacity – I’m connected, but can I send/receive with 100 other devices? • Small cells, lower power • More than 4 devices per person – Laptop – Smartphone – Tablet – Wearables
- 8. 8 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ How To Reach the Goals? RF is like Black Magic, the Dark Arts, etc… Or Is it? • Design, Design, Design • Troubleshooting Accordingly
- 9. 9 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Design, Design, Design
- 10. 10 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ About RF Design Key to a Great Design • Airtime – Be fair and play fair • SNR – Not just RSSI! • Frequency & Channel Reuse – Clients are like 2 year olds, their way or the high way! • Don’t Forget the Backbone – It’s never the RF, it’s those pesky servers!
- 11. 11 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Airtime Basic Design • RSSI Good • Legacy Data Rates On • Longer Waits to Get On • Longer Time On Great Design • RSSI Great • Legacy Data Rates Off • Get On and Off Quickly
- 12. 12 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Airtime Example Download/Upload 1Mb File • 6Mbps Client – 1.33s • 36Mbps Client – 0.22s How Many Users per 5 Minute? • 6Mbps – 230 • 36Mbps - 1363
- 13. 13 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Airtime Calculations Mode (20Mhz, 1ss – 3ss) Receive Sensitivity per Chain (dBm) SNR (dB) @ -95 dBm Noise Floor Legacy 802.11a/g 54 Mbps -75 20 802.11n HT20 MCS7/15 65 – 216 Mbps -71 24 802.11ac VHT20 87 – 289 Mbps -65 30 Great Resource for Calculating Device Airtime: http://www.revolutionwifi.net/p/downloads.html - WLAN Capacity Planning Overview and Worksheets.pdf
- 14. 14 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ SNR SNR is More Important Than RSSI! • RSSI is how strong I hear AP – Doesn’t imply quality • SNR is relationship to noise floor – Changes per site per area per day per environment etc
- 15. 15 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ SNR Example Take datasheet values for AP-220 • 802.11n HT20 • MCS7/15 • 65 – 216 Mbps • 24 SNR Perfect world with -95 dB noise floor says -71 dBm RSSI. Reality says more like -65 dBm or better!
- 16. 16 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Frequency & Channel Reuse Use As Much Frequency As You Can • 2.4GHz – Yes it’s dirty and bloated, but we need it • 5.0GHz – Don’t be shy, client adoption increasing rapidly – Just watch out for DFS channels • 20MHz Channels Might Make More Sense – We don’t always need insane speed but we do need channels
- 17. 17 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Frequency & Channel Reuse • Lower the Power – Just cause an AP does 200mW doesn’t mean you should allow it – Reduce the cell size to allow more channel reuse • Steer When You Can - Client Ultimately Calls the Shots – If it thinks 2.4GHz is better it’ll join there – Always assume a roaming issue will occur
- 18. 18 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Don’t Forget Backbone RF Still Needs Wires & Core Services • DHCP – Active clients vs Associated clients. Makes no difference, they still use an IP if just associated. – Short lease times for guest – example football game is 3 hours, use 3 – 4 hours for lease • AAA Scaling – Account for Web/RADIUS server calls per second for portals – Better yet, forget about the portal!
- 19. 19 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Love Thy Patch
- 20. 20 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Love Thy Patch Learn From Interior Lighting Engineers • Flood or Spotlight? – While a floodlight might work is it the right solution? – Paint the area with RF like you would light. • Omni or Patch? – Same rules apply here as they do with lights. – More precisely control signal spread
- 21. 21 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Patch Example How would you cover a long corridor that never seems to end and provide density coverage?
- 22. 22 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Patch Example Absolutely Not! Omnis Maybe
- 23. 23 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Patch Example Use patch antennas alternating down a hallway. Signal goes where you want, antennas accessible.
- 24. 24 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Demystifying RF With Tools
- 25. 25 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Demystifying RF A screwdriver makes a decent hammer, but a hammer is better. • Survey Tools – Site Survey Software – Spectrum Analysis Software • Packet Tools • Testing Devices
- 26. 26 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Survey Tools Ekahau Site Survey • Predictive Design • Active (AP on Stick) Survey • Post Validation Survey • Proxim 8494 Adapters
- 27. 27 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Spectrum Analyzer Metageek Chanalyzer Pro • USB Form Factor • 2 x Wi-Spy DBx for 2.4 & 5GHz simultaneous • Easy to Use • Report Builder
- 28. 28 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Packet Capture Metageek Eye P.A • Compatible with pcap files • AirPcap direct capture • Visualizes the packet flows
- 29. 29 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Testing Devices Fluke AirCheck • Rugged handheld test device • Consistent readings • Fast startup • Auto Test tool • Import / Export data
- 30. 30 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Testing Devices Fluke LinkSprinter 200 • Extremely portable • PoE, Link, VLAN, DHCP, Internet testing device • WiFi hotspot for advanced mobile display
- 31. 31 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ATMOSPHERE 2014 AIRHEADS@ Questions
- 32. 32 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf DOWNLOAD: Airheads Mobile JOIN: community.arubanetworks.com FOLLOW: @arubanetworks DISCUSS: #AirheadsConf ATMOSPHERE 2014 AIRHEADS@
- 33. 33 Thank You #AirheadsConf CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved