Ixia Black Book: 802.11ac Wi-Fi Benchmarking

Test Case: Latency Benchmark TestIssueTroubleshooting Tipdeliveries during that interval.The key to identify and eliminate these issues is to examine thepacket captures.Test VariablesThe following table lists the parameters you can vary when performing this test.Test VariableTraffic DirectionFrame SizeEncryptionNumber of wirelessclientsClient PHYConfigurationTransmit Power LevelDescriptionIt is common to see vastly different performance profile in theupstream (Wireless to Ethernet) and downstream (Ethernet toWireless) directions. Upstream traffic largely tests an AP’s802.11 receive capabilities, while downstream mostly tests anAP’s transmit capabilities.Testing should be conducted at every frame size to ensure thatthere are no algorithmic bugs that cause performancedegradation at specific frame sizes.The 802.11 standard makes extensive use of encryption toprotect data frame contents. Testing should be conductedwith no encryption, TKIP, and AES encryption (also known asopen, WPA, and WPA2, respectively).Increase the number of wireless clients to validate the DUT’sability to continue to achieve high rates as it needs to handlea larger amount of state information. You may want to run theMaximum Client Capacity test first, in order to determine themaximum number of clients the AP can support under lowstressconditions before running this variation.Each MCS index, channel bandwidth, and guard intervalcondition should be tested to ensure that transmit and receivechains work as expected across all encodings.Performance should be checked at a variety of power levelsto determine the range of input power levels to the AP thatresults in optimal AP performance.Note – higher power is not always better! At higher powerlevels, the RF components can saturate and corrupt the RFPN 915-2634-01 Rev A December 2012 37