'''[wiki:GEC16Agenda/WiMAX-Tutorial/Streamload/07 Previous]''' == Revise, Repeat == After looking at the measurements collected by the 'wxmstat' application, we realize that the signal strength on the nodes is too high. We want a more realistic environment, so we turn down the base station transmit power: {{{ wget -qO- "http://wimaxrf:5052/wimaxrf/bs/set?bs_tx_power=25" wget -qO- "http://wimaxrf:5052/wimaxrf/bs/restart" }}} He also uses the programmable attenuation on Sandbox 4 to create a situation where signal strength varies over the duration of the experiment. To do this, he adds some properties to the beginning of his experiment: {{{ #!ruby defProperty('attUrl', "http://internal2dmz.orbit-lab.org:5052/instr/set?", "Path to use to set attenuation") defProperty('attenuations', [5,6,7,4,3,6,10,11,12,8,7,9,5,3], "List of attenuations to use") }}} and changes the sequence of events in the experiment to look like this: {{{ #!ruby onEvent(:ALL_UP_AND_INSTALLED) do |event| l = property.attenuations wait 5 system("/home/#{ENV['USER']}/getbsconf -i wimaxrf --oml-server tcp:oml:3003 --oml-id console --oml-exp-id #{Experiment.ID}") group("server").exec("/usr/bin/python -m SimpleHTTPServer") group("client1").startApplications l.each do |a| system("/usr/bin/wget -qO- \"#{property.attUrl}portA=#{property.client1}\&portB=9\&att=#{a}\"") wait 5 end group("client1").stopApplications wait 5 group("client2").startApplications l.each do |a| system("/usr/bin/wget -qO- \"#{property.attUrl}portA=#{property.client2}\&portB=9\&att=#{a}\"") wait 5 end group("client2").stopApplications wait 5 allGroups.stopApplications Experiment.done end }}} After running this modified experiment with {{{ omf exec gec16-streamload2.rb }}} He looks at the iRODS plot and is happy with the result. '''[wiki:GEC16Agenda/WiMAX-Tutorial/Streamload/09 Next]'''