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Why Every Engineer Needs WLAN Packet Analysis

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Originally presented at the WirelessLAN Professionals Conference, February 3rd, 2015

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Why Every Engineer Needs WLAN Packet Analysis

  1. 1. www.wildpackets.com© WildPackets, Inc. Why Every Engineer Needs WLAN Packet Analysis How to solve 10 common Wi-Fi problems by dissecting packets Jay Botelho Director of Product Management WildPackets jbotelho@wildpackets.com Follow me @jaybotelho
  2. 2. © WildPackets, Inc. Critical Elements of a Packet Analysis Solution • Performance • Multi-channel analysis • Visualization • Analysis modules • High-quality decodes
  3. 3. © WildPackets, Inc. 10 Common Problems • Verifying device capabilities ‒ Networks ‒ Clients • Verifying device configuration ‒ Poor configuration choices • Connection issues ‒ Authentication • Poor VoFi quality • Identifying network bottlenecks ‒ Chatty clients (let me count the ways) ‒ Probe requests ‒ Inefficient network utilization • Roaming ‒ Sticky clients ‒ Roaming latency
  4. 4. © WildPackets, Inc. Verifying Device Capabilities • Network capabilities – Beacons • Client capabilities – Probe Requests
  5. 5. © WildPackets, Inc. Verifying Device Configuration • QoS enabled/disabled • Beacon intervals • CTS frames sent out with 10,000 microsecond duration field (viewed as duration attack)
  6. 6. © WildPackets, Inc. Connection Issues Authentication – EAPOL Key Exchange • The AP sends a nonce-value to the STA (ANonce) • The STA sends its own nonce- value (SNonce) to the AP together with a MIC, including authentication • The AP sends the GTK and a sequence number together with another MIC • The STA sends a confirmation to the AP
  7. 7. © WildPackets, Inc. Poor VoFi Quality • RTP packets (g.711) • Jitter, packet loss, latency • Relative packet timing
  8. 8. © WildPackets, Inc. Identifying Network Bottlenecks • Chatty clients (let me count the ways) • Probe requests ‒ Probe Requests to all SSIDs, not just current one, flooding device with responses • Inefficient network utilization
  9. 9. © WildPackets, Inc. Chatty Client - Unassociated http://www.sniffwifi.com/2012/04/phones-on-wlan.html
  10. 10. © WildPackets, Inc. Chatty Client - Associated http://www.sniffwifi.com/2012/04/phones-on-wlan.html
  11. 11. © WildPackets, Inc. Inefficient Network Utilization http://www.sniffwifi.com/2014/05/why-are-you-slowing-down-my-wifi-apple.html
  12. 12. © WildPackets, Inc. Inefficient Network Utilization (cont.) http://www.sniffwifi.com/2014/05/why-are-you-slowing-down-my-wifi-apple.html
  13. 13. © WildPackets, Inc. Roaming Issues • Sticky clients ‒ Clients make poor roaming decisions ‒ Look for: signal strength, data rates, etc. • Roaming latency ‒ Criteria for determining latency depends on your perspective http://revolutionwifi.blogspot.com/2012/12/wi-fi-roaming-analysis-part-3-measuring.html
  14. 14. © WildPackets, Inc.
  15. 15. © WildPackets, Inc. Additional Resources • http://www.sniffwifi.com/2012/04/phones-on-wlan.html • http://www.sniffwifi.com/2014/07/i-guess-apple-wireless-routers-dont.html • http://www.sniffwifi.com/2014/05/why-are-you-slowing-down-my-wifi-apple.html • http://www.sniffwifi.com/2013/12/iphones-be-chatty.html • http://www.sniffwifi.com/2013/09/a-fish-in-desert-chomecast-sniffed.html • http://www.sniffwifi.com/2013/08/eighteen-seconds-of-very-chatty-iphone.html • http://www.sniffwifi.com/2012/08/testing-mobility-with-omnipeek.html • http://www.sniffwifi.com/2011/11/how-do-i-know-if-it-really-links-me.html • http://www.sniffwifi.com/2011/11/tell-me-whys-tell-me-sweet-little-whys.html • http://www.sniffwifi.com/2011/11/what-is-wrong-with-this-wifi-and-what.html • http://sc-wifi.com/2013/08/27/troubleshooting-done-motorola-style/ • http://sc-wifi.com/2012/11/12/tag-vendor-specific-nintendo/ • http://www.wifikiwi.com/cwap/a-sticky-problem-wi-fi-clients-that-wont-roam/ • http://revolutionwifi.blogspot.com/2012/12/wi-fi-roaming-analysis-part-3-measuring.html
  16. 16. www.wildpackets.com© WildPackets, Inc. Thank You! WildPackets, Inc. 1340 Treat Boulevard, Suite 500 Walnut Creek, CA 94597 (925) 937-3200

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