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Why Every Engineer Needs WLAN Packet AnalysisHow to solve 10 common Wi-Fi problems by dissecting packetsJay BotelhoDirector of Product ManagementWildPacketsjbotelho@wildpackets.comFollow me @jaybotelhowww.wildpackets.com WildPackets, Inc. WildPackets, Inc.1SynopsisPacket analysis shouldnt be a last resort. It should be an integral part of any WLAN analysis procedure. This step-by-step session will illustrate how to solve 10 common Wi-Fi problems using packet analysis, with a challenge to the audience to describe how anything but packet analysis could find these problems. WildPackets, Inc.Critical Elements of a Packet Analysis SolutionPerformanceMulti-channel analysisVisualizationAnalysis modulesHigh-quality decodes WildPackets, Inc.10 Common ProblemsVerifying device capabilitiesNetworksClientsVerifying device configurationPoor configuration choicesConnection issuesAuthenticationPoor VoFi quality

Identifying network bottlenecksChatty clients (let me count the ways)Probe requestsInefficient network utilizationRoamingSticky clientsRoaming latency

WildPackets, Inc.Verifying Device CapabilitiesNetwork capabilities Beacons

Client capabilities Probe Requests WildPackets, Inc.Verifying Device ConfigurationQoS enabled/disabledBeacon intervalsCTS frames sent out with 10,000 microsecond duration field (viewed as duration attack) WildPackets, Inc.Connection IssuesAuthentication EAPOL Key ExchangeThe 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 authenticationThe AP sends the GTK and a sequence number together with another MICThe STA sends a confirmation to the AP

WildPackets, Inc.Poor VoFi QualityRTP packets (g.711)Jitter, packet loss, latencyRelative packet timing WildPackets, Inc.Identifying Network BottlenecksChatty clients (let me count the ways)Probe requestsProbe Requests to all SSIDs, not just current one, flooding device with responsesInefficient network utilization WildPackets, Inc.Chatty Client - Unassociated

http://www.sniffwifi.com/2012/04/phones-on-wlan.html WildPackets, Inc.Chatty Client - Associated

http://www.sniffwifi.com/2012/04/phones-on-wlan.html WildPackets, Inc.Inefficient Network Utilization

http://www.sniffwifi.com/2014/05/why-are-you-slowing-down-my-wifi-apple.html WildPackets, Inc.Inefficient Network Utilization (cont.)

http://www.sniffwifi.com/2014/05/why-are-you-slowing-down-my-wifi-apple.html WildPackets, Inc.Roaming IssuesSticky clientsClients make poor roaming decisionsLook for: signal strength, data rates, etc. Roaming latencyCriteria for determining latency depends on your perspective

http://revolutionwifi.blogspot.com/2012/12/wi-fi-roaming-analysis-part-3-measuring.html WildPackets, Inc.

WildPackets, Inc.Additional Resourceshttp://www.sniffwifi.com/2012/04/phones-on-wlan.htmlhttp://www.sniffwifi.com/2014/07/i-guess-apple-wireless-routers-dont.htmlhttp://www.sniffwifi.com/2014/05/why-are-you-slowing-down-my-wifi-apple.htmlhttp://www.sniffwifi.com/2013/12/iphones-be-chatty.htmlhttp://www.sniffwifi.com/2013/09/a-fish-in-desert-chomecast-sniffed.htmlhttp://www.sniffwifi.com/2013/08/eighteen-seconds-of-very-chatty-iphone.htmlhttp://www.sniffwifi.com/2012/08/testing-mobility-with-omnipeek.htmlhttp://www.sniffwifi.com/2011/11/how-do-i-know-if-it-really-links-me.htmlhttp://www.sniffwifi.com/2011/11/tell-me-whys-tell-me-sweet-little-whys.htmlhttp://www.sniffwifi.com/2011/11/what-is-wrong-with-this-wifi-and-what.htmlhttp://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 WildPackets, Inc.Thank You!WildPackets, Inc.1340 Treat Boulevard, Suite 500Walnut Creek, CA 94597(925) 937-3200

www.wildpackets.com WildPackets, Inc. WildPackets, Inc.17