# example 4:
#
# Demonstrates the use of some of the tcp statistics gathering
# functions.
#
# author: David Harrison

source $env(NS)/tcl/rpi/tcp-stats.tcl
source $env(NS)/tcl/rpi/script-tools.tcl

Agent/TCP set window_ 1000000   ;# sooo high so it will never hit it!

# bw-rtt product for 1.544Mbps and 24ms rtt is 4.632 packets.
Queue set limit_ 10

set ns [new Simulator]
use-nam

proc finish {} {
  global n0 n1 tcp0 tcp1

  puts "TCP statitics: "
  puts "Number of data packets transmitted by flow 0: \
    [$tcp0 set ndatapack_]"
  puts "Number of data packets transmitted by flow 1: \
    [$tcp1 set ndatapack_]"
  puts "Retransmission timeouts for flow 0: \
    [$tcp0 set nrexmit_]"
  puts "Retransmission timeout for flow 1: \
    [$tcp1 set nrexmit_]"

  if { [info exists tcp0] } {
    puts "$tcp0 exists"
  }
  puts "Goodput (in bps): [$tcp0 get-goodput-bps]"
  puts "Goodput Variance: \
    [get-goodput-stddev "$tcp0 $tcp1"]"
  puts "Total TCP packets: \
    [get-total-data-packets "$tcp0 $tcp1"]"

  run-nam
  exit 0
}

# create a topology containing two sources and two destinations.
set s0 [$ns node]
set d0 [$ns node]
set s1 [$ns node]
set d1 [$ns node]
set n0 [$ns node]
set n1 [$ns node]

# create links.
$ns duplex-link $s0 $n0 10M 4ms DropTail
$ns duplex-link $s1 $n0 10M 4ms DropTail
$ns duplex-link $n0 $n1 1.544M 4ms DropTail
$ns duplex-link $n1 $d0 10M 4ms DropTail
$ns duplex-link $n1 $d1 10M 4ms DropTail

set tcp0 [lindex [create-ftp-over-reno $s0 $d0 0.5 0] 0]
set tcp1 [lindex [create-ftp-over-reno $s1 $d1 0.8 1] 0]

$tcp0 init-stats
$tcp1 init-stats

# set colors for each flow
$ns color 0 Blue 
$ns color 1 Red 

# arrange links for nam
$ns duplex-link-op $n0 $n1 queuePos 0.5
$ns duplex-link-op $s0 $n0 orient 1.75
$ns duplex-link-op $s1 $n0 orient 0.25
$ns duplex-link-op $n0 $n1 orient right
$ns duplex-link-op $n1 $d0 orient 0.25
$ns duplex-link-op $n1 $d1 orient 1.75


$ns at 8 finish
$ns run