NS2 TCP

What is TCP:

TCP stands for Transmission Control Protocol which defines how computers should be connected over the Internet, and how data should be transmitted between them.
Before send data to the network TCP splits data into smaller packets then assembling those packets when they arrive.

Common TCP protocols:

HTTP – Hyper Text Transfer Protocol
HTTPS – Secure HTTP
FTP – File Transfer Protocol

TCP Protocols for Email:

SMTP – Simple Mail Transfer Protocol
MIME – Multi-purpose Internet Mail Extensions
POP – Post Office Protocol
IMAP – Internet Message Access Protocol

Other TCP Protocols:

ARP – Address Resolution Protocol
DHCP – Dynamic Host Configuration Protocol
BOOTP – Boot Protocol
ICMP – Internet Control Message Protocol
NTP – Network Time Protocol
LDAP – Lightweight Directory Access Protocol
PPTP – Point to Point Tunneling Protocol
SSL – Secure Sockets Layer
RARP – Reverse Address Resolution Protocol
TLS – Transport Layer Security
SNMP – Simple Network Management Protocol

TCP Sink Agents in ns2:

TCP../ns-2/tcp.h is a simplified TCP sender which sends data packets to a TCPSink agent after that processes its acknowledgments.

TCP connection termination:

TCP connection termination phase uses a four-way handshake.

CODE:

proc build-fore-tcp { idx size intv stime } {
global ns ftcp fsink
set ftcp($idx) [new Agent/TCP/Newreno]
set fsink($idx) [new Agent/TCPSink]
$ns at $stime “start-conn 1 $idx $intv $size”
}
proc start-conn

{ firsttime idx intv size

}

{ global ns ftcp fsink s r
set now [$ns now]
if { $firsttime == 0 }

{
$ns detach-agent $s([expr $idx%2]) $ftcp($idx)
$ns detach-agent $r([expr $idx%2]) $fsink($idx)
$ftcp($idx) reset
$fsink($idx) reset
}
$ns attach-agent $s([expr $idx%2]) $ftcp($idx)
$ns attach-agent $r([expr $idx%2]) $fsink($idx)
$ns connect $ftcp($idx) $fsink($idx)
$ftcp($idx) set fid_ 0
$ftcp($idx) proc done {} “close-conn $idx $intv $size”
$ftcp($idx) advanceby $size
}
proc close-conn { idx intv size }

{
global ns
set now [$ns now]
$ns at [expr $now + $intv] “start-conn 0 $idx $intv $size”
puts “at $now + $intv start next”
}
set forel_intv 1
set fores_intv 0.05
set ssize 4
set lsize 1000
build-fore-tcp 1 $ssize 1 0.1
build-fore-tcp 0 $lsize $forel_intv 0.5
for {set i 0} {$i < 5} { incr i} {
build-fore-tcp [expr 2*$i+3] $ssize $fores_intv [expr 1.2+$i*0.1]
}