Flow Control Efficiency Calculator {title: ""}, {title: "Efficiency [%]", viewWindowMode: "explicit", viewWindow: {max: 100}, viewWindow: {min: 0}}

Calculates the efficiency of stop-and-wait (W=1) and sliding-window (W>1) flow control algorithms for given link and traffic characteristics.

Algorithm

Stop-and-wait flow control is a specific case of sliding window when W=1. To choose stop-and-wait, simply select a window size of 1. For W > 1, sliding window is used.

Maximum window size, W frames

Link A to B

Data rate, r_AB Mb/s
Distance, d_AB km
Speed, s_AB m/s

Link B to A

Data rate, r_BA Mb/s
Distance, d_BA km
Speed, s_BA m/s

Processing at A

Before transmit DATA, proc_Atx us
After receive ACK, proc_Arx us

Processing at B

After receive DATA, proc_Brx us
Before transmit ACK, proc_Btx us

DATA frame

Header, b_header Bytes
Payload, b_payload Bytes
Trailer, b_trailer Bytes

ACK Frame

Header, b_ack Bytes

Other

Time units >seconds (s) >milliseconds (ms) >microseconds (us) >nanoseconds (ns)

Note that the time units are only applied in the results. The time units used above for the input parameters are fixed, e.g. you must give the processing delays in microseconds (us).

Plot

Results are calculated for the above parameter values. Optionally, you can also generate a plot that shows the efficiency for a range of values of one selected parameter. Select that parameter below, and its maximum value in the range. The minimum value will be taken from the value specified above. For example, if above you chose a window size of 1, and then below you select the Max window size parameter, and set the Max value to 10, then a plot for flow control efficiency with window ranging from 1 to 10 will be produced.

Parameter 1 >none >Max window size >Link data rate >Link distance >DATA header >DATA payload >ACK size
Max value

= $total_delay) { $efficiency=100*(($traffic_payload * 8) / ($linkab_datarate*1000000) * $system_timemultiplier) / ($data_trans + ($proca_before / 1000000 * $system_timemultiplier)); $throughput=$efficiency * $linkab_datarate * 1000000 / 100; } else { $throughput=($window_max * $traffic_payload * 8) / ($total_delay / $system_timemultiplier); $efficiency=100*$throughput / ($linkab_datarate*1000000); } return $efficiency; } $data_trans=($traffic_header + $traffic_payload + $traffic_trailer) * 8 / ($linkab_datarate*1000000) * $system_timemultiplier; $linkab_prop=($linkab_distance * 1000) / $linkab_speed * $system_timemultiplier; $ack_trans=($traffic_ack) * 8 / ($linkba_datarate*1000000) * $system_timemultiplier; $linkba_prop=($linkba_distance * 1000) / $linkba_speed * $system_timemultiplier; $other_delay=($proca_before + $proca_after + $procb_after + $procb_before) / 1000000 *$system_timemultiplier; $total_delay=$data_trans + $linkab_prop + $ack_trans + $linkba_prop + $other_delay; if ($window_max * ($proca_before / 1000000 * $system_timemultiplier + $data_trans) >= $total_delay) { $efficiency=100*(($traffic_payload * 8) / ($linkab_datarate*1000000) * $system_timemultiplier) / ($data_trans + ($proca_before / 1000000 * $system_timemultiplier)); $throughput=$efficiency * $linkab_datarate * 1000000 / 100; } else { $throughput=($window_max * $traffic_payload * 8) / ($total_delay / $system_timemultiplier); $efficiency=100*$throughput / ($linkab_datarate*1000000); } ?>

Results

DATA transmission, trans_DATA
A to B transmission, prop_AB
ACK transmission, trans_ACK
B to A propagation, prop_BA
Other delays
Delay of 1 exchange

Throughput, t b/s
Efficiency, n %

$plot_value1) { $min_value=$plot_value1; $max_value=$init_value; } else { $min_value=$init_value; $max_value=$plot_value1; } $j=0; for ($i=$min_value; $i<=$max_value+($max_value-$min_value)/$plot_steps; $i=$i+($max_value-$min_value)/$plot_steps) { $x[$j]=round($i,0); $y[$j]=calculateEfficiency($linkab_datarate, $linkab_distance, $linkab_speed, $linkab_datarate, $linkab_distance, $linkab_speed, $proca_before, $proca_after, $procb_before, $procb_after, $traffic_header, $traffic_payload, $traffic_trailer, $traffic_ack, round($i,0), $system_timemultiplier); $j++; } } if ($plot_parameter1=="link_datarate_2") { $htitle1="Link Data Rate [Mb/s]"; $init_value=$linkab_datarate; if ($init_value > $plot_value1) { $min_value=$plot_value1; $max_value=$init_value; } else { $min_value=$init_value; $max_value=$plot_value1; } $j=0; for ($i=$min_value; $i<=$max_value+($max_value-$min_value)/$plot_steps; $i=$i+($max_value-$min_value)/$plot_steps) { $x[$j]=$i; $y[$j]=calculateEfficiency($i, $linkab_distance, $linkab_speed, $i, $linkab_distance, $linkab_speed, $proca_before, $proca_after, $procb_before, $procb_after, $traffic_header, $traffic_payload, $traffic_trailer, $traffic_ack, $window_max, $system_timemultiplier); $j++; } } if ($plot_parameter1=="link_distance_2") { $htitle1="Link Distance [km]"; $init_value=$linkab_distance; if ($init_value > $plot_value1) { $min_value=$plot_value1; $max_value=$init_value; } else { $min_value=$init_value; $max_value=$plot_value1; } $j=0; for ($i=$min_value; $i<=$max_value+($max_value-$min_value)/$plot_steps; $i=$i+($max_value-$min_value)/$plot_steps) { $x[$j]=$i; $y[$j]=calculateEfficiency($linkab_datarate, $i, $linkab_speed, $linkab_datarate, $i, $linkab_speed, $proca_before, $proca_after, $procb_before, $procb_after, $traffic_header, $traffic_payload, $traffic_trailer, $traffic_ack, $window_max, $system_timemultiplier); $j++; } } if ($plot_parameter1=="traffic_header_2") { $htitle1="DATA Header [Bytes]"; $init_value=$traffic_header; if ($init_value > $plot_value1) { $min_value=$plot_value1; $max_value=$init_value; } else { $min_value=$init_value; $max_value=$plot_value1; } $j=0; for ($i=$min_value; $i<=$max_value+($max_value-$min_value)/$plot_steps; $i=$i+($max_value-$min_value)/$plot_steps) { $x[$j]=$i; $y[$j]=calculateEfficiency($linkab_datarate, $linkab_distance, $linkab_speed, $linkab_datarate, $linkab_distance, $linkab_speed, $proca_before, $proca_after, $procb_before, $procb_after, $i, $traffic_payload, $traffic_trailer, $window_max, $traffic_ack, $system_timemultiplier); $j++; } } if ($plot_parameter1=="traffic_payload_2") { $htitle1="DATA Payload [Bytes]"; $init_value=$traffic_payload; if ($init_value > $plot_value1) { $min_value=$plot_value1; $max_value=$init_value; } else { $min_value=$init_value; $max_value=$plot_value1; } $j=0; for ($i=$min_value; $i<=$max_value+($max_value-$min_value)/$plot_steps; $i=$i+($max_value-$min_value)/$plot_steps) { $x[$j]=$i; $y[$j]=calculateEfficiency($linkab_datarate, $linkab_distance, $linkab_speed, $linkab_datarate, $linkab_distance, $linkab_speed, $proca_before, $proca_after, $procb_before, $procb_after, $traffic_header, $i, $traffic_trailer, $traffic_ack, $window_max, $system_timemultiplier); $j++; } } if ($plot_parameter1=="traffic_ack_2") { $htitle1="ACK Header [Bytes]"; $init_value=$traffic_ack; if ($init_value > $plot_value1) { $min_value=$plot_value1; $max_value=$init_value; } else { $min_value=$init_value; $max_value=$plot_value1; } $j=0; for ($i=$min_value; $i<=$max_value+($max_value-$min_value)/$plot_steps; $i=$i+($max_value-$min_value)/$plot_steps) { $x[$j]=$i; $y[$j]=calculateEfficiency($linkab_datarate, $linkab_distance, $linkab_speed, $linkab_datarate, $linkab_distance, $linkab_speed, $proca_before, $proca_after, $procb_before, $procb_after, $traffic_header, $traffic_payload, $traffic_trailer, $i, $window_max, $system_timemultiplier); $j++; } } } ?>

Created on Fri, 31 Aug 2012, 6:10pm

Last changed on Wed, 07 Aug 2013, 12:07pm