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WLAN Design for Location, Voice and Video

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• Enabling multimedia services on wireless networks is a great idea nowadays, especially given the user demand. But it takes more access points to install, proactive planning for application level …

• Enabling multimedia services on wireless networks is a great idea nowadays, especially given the user demand. But it takes more access points to install, proactive planning for application level performance requirements and multimedia aware RF management functions. Join us to learn about multimedia application behavior and how you can get your wireless network ready.
To learn more, visit us at http://www.arubanetworks.com/wlan. Join the discussion at https://community.arubanetworks.com

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  • 1. WLAN Design for Location, Voice and Video Abhinethra Maras, Ashutosh Dash March 2014
  • 2. CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved 2 #AirheadsConf Agenda • Design Guidelines for WiFi grade Location • Design Guidelines for WiFi grade Voice • Design Guidelines for WiFi grade Video • QOS and Traffic Optimization • Enterprise Diagnostics and Troubleshooting
  • 3. CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved 3 #AirheadsConf Agenda • Analytics and Location Overview • ALE System Overview • Indoor Location Technology • Probing • Recommendations • Summary
  • 4. 4 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Analytics and Location Overview
  • 5. 5 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Analytics & Location Ecosystem Big Data Analytics Partners Network Applications Cloud Applications User Context (who, what, where, when) Location Applications (Wayfinding, etc) Context: 1. Location 2. Applications 3. Destinations 4. Identity 5. Device types ALE (Context Aggregation)
  • 6. 6 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ALE System Overview
  • 7. 7 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Analytics and Location Engine (ALE) Overview ALE Unified context for each user (user name, IP, MAC, device type, App visibility, etc.) 1 Seamless, secure cloud connectivity 4 Real time location engine 2 Standard, high performance northbound APIs (publish/ subscribe, polling) 3
  • 8. 8 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Data Collected & Provided by ALE • Presence feed • Events when a device is detected crossing a Geofence • Device information • User information from authentication to the network • Applications used • Destination URLs
  • 9. 9 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ALE Enabled Use Cases ALE Use cases People movement, congested paths 1 Way-finding (turn- by-turn directions 2 Way-finding (turn- by-turn directions Busy times by location Web analytics Energy management 4 3 5 6
  • 10. 10 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ALE System Overview Local Controller Remote Controllers NETWORK Instant APs Campus/Rem ote APs Visual RF SERVICES Context aggregation, location engine ALE VM Location data for visualization on maps APPLICATIONS Context visualization, analytics Northbound APIs: REST, Protobuf/OMQ Context Data
  • 11. 11 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Understanding Probe Flow and Location ALE Client pulls its location from the cloud every __ seconds? Probes between few seconds to 10s of minutes 1 AP sends RSSI on a timer, default is 30 secs, can be set to 1 sec (6.3.1.1) (Future: Will be instantaneous) 2 Controller sends the data on a fixed timer of 10 seconds (Future: Will be instantaneous) 3 ALE calculates the location, latency varies based on the settings. 4
  • 12. 12 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Indoor Location Technology
  • 13. 13 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Indoor Location Technology Overview • Satellite-based GPS does not work indoors • Two main approaches to indoor positioning technology: – Device-based scans of radio signals (software/hardware) – Network-based scans of device radio signals (Wi-Fi) • No standard indoor positioning solution exists today • Indoor positioning (relative to the venue layout) requires indoor maps • Layouts within locations often change
  • 14. 14 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Device vs Wi-Fi Network Based Location Device-based software The device performs signal scans of nearby network signals to analyzes signal strengths to calculate position Wi-Fi network based The network APs perform signal scans of Wi-Fi traffic and analyzes the device’s Wi- Fi signal strength to calculate position
  • 15. 15 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Location Positioning Technology How Information is Transmitted GPS Geofencing Cell Phone Triangulatio n Cell Towers How Info is Transmitted Hardware Required RequiresOnsiteFingerprinting BLE LED Light Pulses Sensor Fusion Device-Based Signal Triangulation RTLS Network-Based Wi-Fi Triangulation Existing Wireless APs LED Lights With Chips Wi-Fi Hotspots BLE Beacons or Nodes Wi-Fi Hotspots Audio Queue Sound Emission Devices Outside Venue Inside Venue
  • 16. 16 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf GPS –Triangulation from Satellites
  • 17. 17 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Indoor Location Positioning Technology  Wi-Fi must be turned on/enabled on the device Network-Based Wi-Fi Positioning • Devices are constantly scanning for Wi-Fi • The network does the work • Analytics can be delivered without device app • More battery efficient for mobile devices • Can work with any device, including iPhones, Android, etc. Used by:
  • 18. 18 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf The Wi-Fi Location Puzzle • Sparse samples – Easier & better from infrastructure than from device – +/- 5dB inter-frame variation – Clients want to minimize radio activity > maximize battery life – Floor-level signal differs from ceiling-level – Absence of signal does not mean a device is absent • Frame of reference for signal sources / sinks – Where are the AP locations? Tx Pwr? Directional antennas? – ARM changes RF Plan • Frame of reference – local or global (Lat/Long) or civic? – Enterprise and indoor apps mostly use local maps – Google, Bing etc use Lat/Long • Parametric or non-parametric? – Build a synthetic heatmap using RF propagation model – Or use AP-AP and other calibration and non-parametric curve-fitting (e.g. Gaussian Process) • Speed vs accuracy tradeoff • Add Helpers – GPS, celltower, Bluetooth beacons, BSSID surveys – On-board compass, accelerometers – Estimates for motion vectors and earlier position fixes – Knowledge of walls, doors and snap-to-grid tramlines
  • 19. 19 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Probing • Again….location calculation today purely relies on client probes – NO PROBES…..NO LOCATION!! • Unassociated devices will Probe more than associated – If associated device is happily connected, it will not bother Probing. • iOS devices Probe less than Android (battery life considerations). – Meridian and Aruba Utilities (mobile apps) can stimulate Probes on Android. – iOS does not expose any such API (to cause Wi0Fi scan) • Going on Settings->Wifi on iOS will trigger Probes. If you want to stimulate Probes on iOS, either unassociate, or occasionally keep going to the Settings->Wifi page. • A device must be heard by 3 or more APs to calculate location
  • 20. 20 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf RSSI Based Locationing • The raw data for location estimation is the received signal strength (RSSI) of Wi-Fi frames received from client devices – RSSI is inherently variable due to fluctuating RF conditions, the geospatial attitude of the mobile device and its proximity and relationship to human tissue – We expect a variation of RSSI in the order of 6dB even when the person holding the device is stationary – As the distance from the AP increases, the RSSI - distance curve flattens
  • 21. 21 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Location: Accuracy & Latency Accuracy • Impacted by various factors: – AP density, type, mounting type – Physical Environments, enterprise, malls, warehouse, etc. – RSSI variations – Client probing behavior, device type, OS type Latency • Impacted by – Client probe frequency (iOS vs Android) – Network settings: AP/controller timers – Engine smoothening algorithms • Balance between accuracy and latency ALE goal is to be <10m 90% of time on a location grade network
  • 22. 22 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Location Applications in PFE • Location has different facets: – Presence (Inside a Store/Zone or outside) • Useful for push notifications – Wayfinding (“Blue Dot”) • Useful in ultra large venues • Most Location applications of practical value in PFE fall under “Presence” category • Location Services are the not the only “PFE” applications – Guest Access, support for enterprise apps, multimedia support, device onboarding, etc., are all applicable to PFE Presence Way- Finding
  • 23. 23 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Design Considerations for Locationing • Start with a good understanding of commercial requirements • What is the key use case and “true” requirement? – Self directed museum tour? • In which case latency will not be an issue – Ability to locate specific venue (conference room, restaurant, etc.) within a large venue or a product with turn by turn directions? – “Presence detection” in stores in a shopping mall? • Knowledge of the use case is key to understanding location accuracy, latency requirements
  • 24. 24 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf AP Placement Guidelines (1) • RSSI location uses triangulation techniques – This needs at least three APs to receive a target’s transmissions at relatively short range to give a good location. • Best indicator of location accuracy is AP spacing • Studies and experience show that regularly spaced APs give the best overall location accuracy. – Most WLAN planning tools produce a regular grid pattern of APs in the absence of local propagation information • Our best advice is to take the output of such tools – or a wireless engineer’s design with regular AP spacing - and adjust the output to take account of local knowledge: • Areas that present special challenges or where accurate location is more important should
  • 25. 25 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf AP Placement Recommendation (2) • Do: – Place AP every 2500 sq. feet or 50 feet apart – Cover the extremities! – 65 dbm coverage (“Voice Grade) – Ensure AP placement on floor plan is accurate – Stagger AP placement in multi-floor buildings • Do Not: – Place AP in straight lines – Design for coverage only & not enough density • The standard topology is a ‘square’ grid pattern of APs, but there is research indicating a hexagonal pattern gives better results • Aruba is testing this configuration
  • 26. 26 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf AP Placement: Voice Overlay Design
  • 27. 27 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf AP Placement Recommendations Summary Recommendation Priority Comments Voice Overlay 1 This is a must in all deployments to achieve triangulation which is core requirement of location calculation. AP every 2500 sq. feet or 50 feet apart and cover the edges 1 This is help achieve a good coverage pattern and triangulation and is must for most deployments. Hexagonal pattern for AP layout 2 This is recommended but might be hard to achieve in certain scenarios due to the physical layout. -65 dbm coverage 2 This is strongly recommended but might be hard to achieve in certain parts of a building. In those cases, ensure that there is at least a -75 dbm coverage in those areas.
  • 28. 28 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf RF Design Guidelines for Voice & Video
  • 29. 29 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Pervasive RF Coverage • 100% coverage in all areas of Voice use • Capacity based Wireless network design recommended – Higher number APs operating with low TX Power – Small Cell sizes, clients use higher data rates Coverage design with 7.2 Mb/s cell edge Capacity design with 216.7 Mb/s cell edge
  • 30. 30 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf ARM Features for Voice • Interference Aware • Band Steering • Spectrum Load Balancing • Voice/Video Aware Scanning
  • 31. 31 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Clientmatch • Deterministic steering of clients based on the SNR and signal level information gathered from client's perspective • Steering decision is based on the probes request from the client • Periodic load balancing • Resolves Sticky-client issue
  • 32. 32 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf RF Design Best Practices for Voice • Pervasive RF Coverage • Distance between APs to not exceed 50 Ft • Minimum RF signal (RSSI) levels of -65 dBm • Minimum signal-to-noise ratio (SNR) of 25 dB • Minimum and maximum AP power difference no greater than two steps • Disable lower data rates • In the Adaptive Radio Management™ (ARM) profile – Enable voice/video aware scan – ClientMatch™-enabled
  • 33. 33 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf RF Design Best Practices for Voice (continued) • Configure Supported Beacon rate to higher rate • Enable WMM Traffic Management • Give higher of bandwidth to Voice and Video • Enable Fair access • Provide high % of bandwidth to a VAP (For example, assign higher % bandwidth to Corp VAP than Guest VAP)
  • 34. 34 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Best Practices for Video • RF Best practices for Voice applies to Video as well • Best practices for Delivering multicast video • Enable IGMP Snooping Or IGMP Proxy • Enable Dynamic Multicast Optimization (DMO) • Enable Decrypt-tunnel Dynamic Multicast Optimization (D-DMO)
  • 35. 35 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Designing a Roaming Network
  • 36. 36 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Designing a Roaming Network • Difference in power levels on the deployed APs should not be too high • Airtime fairness is recommended in an environment with mobile clients to avoid slower clients taking too much airtime • In a dot1x environment, enable EAPOL rate optimization • For faster roaming, use OKC and 802.11r • Enable ClientMatch to help with sticky client problem • Match QoS markings that the devices are using
  • 37. 37 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Authentication/Encryption Guidelines
  • 38. 38 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Authentication/Encryption Guidelines • 802.1x based authentication through radius server may introduce delay during re-association/roaming • Use Opportunistic Key Caching with 802.1x for faster roaming • PSK works better for voice devices (less delay), but not a preferred method due to weak security • EAP-TLS provides the best security and is preferred in enterprises rather than EAP-PEAP
  • 39. 39 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf End-to-End QoS
  • 40. 40 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf QoS Segments LAN core LAN edge Wireless Tagged DSCP, 802.1p Tagged DSCP, 802.1p WMM / strict queuing Tagged DSCP, 802.1p Tagged DSCP, 802.1p WMM / SVP Bandwidth management call admission control QoS aware RF management Bandwidth Management Tagging Upstream traffic Downstream traffic
  • 41. 41 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Deep Dive into DSCP and WMM AC
  • 42. 42 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf QOS - Tunnel Mode Client No Tag (WMM Only) Aruba Mobility Controller AP Client-A, VO: DSCP 0 Client-B, VO: DSCP 0 DSCP 0 WMM BE DSCP 24 WMM BE DSCP 24 DSCP 24 VO: 46 VI: 34 BE: 24 Summary: • AP looks at L2 Priority and puts the DSCP as per DSCM-WMM mapping in controller • Controller decrypts the packet and uses L2 priority to assign DSCP mapping in downstream direction Controller decrypts the packet and retags as per L2 priority AP looks at L2 priority and puts DSCP as per DSCP to WMM mapping
  • 43. 43 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf QOS - Tunnel Mode (WMM Only) Aruba Mobility Controller AP Client-A, VO: DSCP 46 Client-B, VO: DSCP 46 DSCP 46 WMM VI DSCP 34 WMM VI DSCP 34 DSCP 34 Summary: • AP looks at L2 Priority and puts the DSCP as per DSCM-WMM mapping in controller • Controller decrypts the packet and uses L2 priority to assign DSCP mapping in downstream direction Controller decrypts the packet and retags as per L2 priority AP looks at L2 priority and puts DSCP as per DSCP to WMM mapping VO: 46 VI: 34 BE: 24
  • 44. 44 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf QOS - Tunnel Mode (Lync Heuristics for Voice) Aruba Mobility Controller AP Client-A, VO: DSCP 46 Client-B, VO: DSCP 46 DSCP 46 WMM VI DSCP 46 WMM VO DSCP 46 DSCP 34 Summary: • AP looks at L2 priority and puts the DSCP as per DSCM-WMM mapping in controller • Lync heuristics determines the AC based on the codec. If the codec used is voice, it gives DSCP value corresponding to voice. Controller decrypts the packet and retags as per traffic type AP looks at L2 priority and puts DSCP as per DSCP to WMM mapping VO: 46 VI: 34 BE: 24
  • 45. 45 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Troubleshooting and Diagnostics
  • 46. 46 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Troubleshooting Guidelines • Are RF and other Configuration Best Practices in place? • Does your Network have end-to-end QoS? • Can you isolate if it is an RF Network issue Or Wired Network? • If required, enable debugging at controller to get detail logs • For example, if you are using Voice ALGs (Sip, Lync), enable the following command to troubleshoot voice issues: (SE_PFE_1) (config) #logging level debugging user process stm subcat voice (SE_PFE_1) (config) #show log user all
  • 47. 47 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Troubleshooting and Diagnostics Demo
  • 48. 59 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Voice Overlay Airwave
  • 49. 60 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved #AirheadsConf Airwave – Client Troubleshooting
  • 50. 61 CONFIDENTIAL © Copyright 2014. Aruba Networks, Inc. All rights reserved Thank You #AirheadsConf