1 # Basic Incast Simulation  2 # Check Args  3 if {$argc != 5} {  4   puts "Usage: ns incast <srv_num> <adv_win-pkt> <SRU-KB> <link_buf-pkt> <seed>"  5   exit 1  6 }  7   8 #################################################################  9 # Argments 10 # ServerNum: $argv(0) 11 set svr_num [lindex $argv 0] 12 # Advertised Window size (pkt): $argv(1) 13 set adv_win [lindex $argv 1] 14 # SRU Size (Byte) ... only Payload: $argv(2) 15 set SRU [expr [lindex $argv 2] * 1024] 16 # Link Buffer (pkt): $argv(3) 17 set link_buf [lindex $argv 3] 18 # Random Seed: $argv(4) 19 set seed [lindex $argv 4] 20  21 ################################################################ 22 # Variables 23 # Create a simulator object 24 set ns [new Simulator] 25  26 # Bandwidth (Gbps) 27 set bw_Gbps 1 28  29 # Link Delay (us) 30 set link_del_us 25 31 # Maximum Random Link Delay: 0--maxrand (us) 32 set maxrand_link_del_us 20 33  34 # SYN Interval Delay (us) for each Request 35 set SYN_del_us 0 36 ## For Aggressive Optimization for Goodput (may cause incast) 37 # set SYN_del_us [expr int(${SRU} * 8 / (${bw_Gbps} * pow(10, 9)) * pow(10, 6))] 38 ## For Conservative Optimization for Goodput (never cause incast) 39 # set SYN_del_us [expr int(${SRU} * 8 / (${bw_Gbps} * pow(10, 9)) * pow(10, 6)\ 40 #   + ${link_del_us} * 4 * (1 +  41 #   (log10( ${link_del_us} * 4 * pow(10, -6) * ${bw_Gbps} * pow(10, 9)  42 #   / (1500 * 8) ) / log10(2))))] 43  44 # Maximum Random SYN Delay: 0--maxrand (us) 45 set maxrand_SYN_del_us 0 46  47 # Total Size of All Servers SRU with TCP/IP Header and Handshake 48 set Block_trans [expr ((int($SRU / 1460) + 1)* 1500 + 40) * $svr_num] 49  50 # Link Error Rate (Unit:pkt) 0.001 = 0.1% (a loss in 1000 pkt) 51 # set err_rate 0.001 52 set err_rate 0 53  54 ############################################# 55 # Random Model 56 set rng [new RNG] 57 # seed 0 equal to current OS time (UTC) 58 # so seed should be more than 1 for repeatability 59 $rng seed [expr ${seed} * ${svr_num} + 1] 60  61 ################################################################# 62 # Tracing Message 63 puts -nonewline "Server: $svr_num, win: ${adv_win}pkt, " 64 puts -nonewline "SRU: [lindex $argv 2]KB, link_buf: ${link_buf}pkt, " 65 puts "Seed: $seed, " 66 puts -nonewline "Block_trans: ${Block_trans}B, " 67 puts -nonewline "RTT: [expr $link_del_us * 4]us, " 68 puts -nonewline "RTT_rand: ${maxrand_link_del_us}us, " 69 puts "SYN_del: ${SYN_del_us}-[expr $SYN_del_us + $maxrand_SYN_del_us]us" 70  71 Agent/TCP set trace_all_oneline_ true 72 Agent/TCP set packetSize_ 1460 73 Agent/TCP set window_ $adv_win 74 Agent/TCP set singledup_ 0 ;      # 0: Disabled Limited Transmit 75 Agent/TCP set tcpTick_ 0.0000001 ;  # 100ns (default 0.01: 10ms) 76 Agent/TCP set minrto_ 0.2 77  78 #Open the ns trace file 79 set nf [open out.ns w] 80 $ns trace-all $nf 81 set ef [open out.et w] 82 $ns eventtrace-all $ef 83 set tf [open out.tcp w] 84 # For Queue Monitoring 85 # set q_trans [open queue_trans.ns w] 86  87 proc finish {} { 88     global ns nf ef tf 89     # For Queue Monitoring 90     # global q_trans 91     $ns flush-trace 92     close $nf 93     close $tf 94     close $ef 95     # close $q_trans 96     puts "Done." 97     exit 0 98 } 99 100 #Create two nodes101 set nx [$ns node]102 set nc [$ns node]103 $ns duplex-link $nx $nc ${bw_Gbps}Gb ${link_del_us}us DropTail104 $ns queue-limit $nx $nc ${link_buf}105 106 # Link Error Module between Switch and Client107 set loss_module [new ErrorModel]108 $loss_module unit pkt109 $loss_module set rate_ $err_rate110 set loss_random_variable [new RandomVariable/Uniform]111 $loss_random_variable use-rng ${rng}112 $loss_module ranvar ${loss_random_variable}113 $loss_module drop-target [new Agent/Null]114 $ns lossmodel $loss_module $nx $nc115 116 for {set i 0} {$i < $svr_num} {incr i} {117     set n_($i) [$ns node]118     $ns duplex-link $nx $n_($i) ${bw_Gbps}Gb ${link_del_us}us DropTail119     $ns queue-limit $n_($i) $nx 1000120     set tcp_($i) [new Agent/TCP/Newreno]121     $tcp_($i) set fid_ $i122     $tcp_($i) attach-trace $tf123     $tcp_($i) trace maxseq_124     $tcp_($i) trace ack_125     set ftp_($i) [new Application/FTP]126     $ftp_($i) attach-agent $tcp_($i)127     $ftp_($i) set type_ FTP128     $ns attach-agent $n_($i) $tcp_($i)129     set snk_($i) [new Agent/TCPSink]130     $ns attach-agent $nc $snk_($i)131     $ns connect $tcp_($i) $snk_($i)132 133     # Caluclate Delay (us)134     set del_us [expr $link_del_us * 2 + $SYN_del_us * $i \135                     + [$rng uniform 0 ${maxrand_SYN_del_us}]]136 137      $ns at [expr 1.0 + $del_us * 0.000001] "$ftp_($i) send $SRU"138 }139 $ns at 0.0 "debug"140 $ns at 0.99 "check_trans"141 $ns at 21.0 "finish"142 143 # For Queue Monitoring144 # set q_mon [$ns monitor-queue $nx $nc [open queue_mon.ns w] 0.0001]145 # [$ns link $nx $nc] queue-sample-timeout146 147 proc update_link_del {} {148     global ns nx n_ link_del_us maxrand_link_del_us svr_num rng149     for {set i 0} {$i < $svr_num} {incr i} {150         $ns delay $nx $n_($i) [expr $link_del_us \151                + [$rng uniform 0 ${maxrand_link_del_us}]]us duplex152     }153 }154 155 proc check_trans {} {156     global ns Block_trans svr_num snk_157     # 0.0001 = 100 us = 1 RTT158     set time 0.0001159     set now [$ns now]160 161     # check traffic to each TCP sink agent162     # puts "$now: Server: 0, bytes: [$snk_(0) set bytes_]"163     set total_bytes 0164     for {set i 0} {$i < $svr_num} {incr i} {165         set total_bytes [expr $total_bytes + [$snk_($i) set bytes_]]166     }167 168     # Is any data to be transmitted?169     if {$total_bytes >= $Block_trans} {170         # All SRU is transmitted.171         if {$total_bytes == $Block_trans} {172             # Finish in just.173         } else {174             # Unnecessary Retransmit is exist.175         }176         flush stdout177         $ns at [expr $now + 1] "finish"178     }179 180     # For Queue Monitoring181     # $q_mon instvar parrivals_ pdepartures_ bdrops_ bdepartures_ pdrops_182     # puts $q_trans "$now $bdepartures_"183 184     # For update_link185     update_link_del186 187     $ns at [expr $now+$time] "check_trans"188 }189 190 proc debug {} {191     global ns192     set next_time 1.0193     set now [$ns now]194     puts -nonewline "$now."195     flush stdout196     $ns at [expr $now+$next_time] "debug"197 }198 199 #Run the simulation200 $ns run