5. VTU COMPUTER NETWORK LAB | READ NOW

VTU COMPUTER NETWORK LAB

Program 5:- Implement and study the performance of GSM on NS2/NS3 (Using MAC layer) or
equivalent environment

Program Code

#set Parameters 
set stop 100	;# Stop time. 

# Topology 
set type gsm	;#type of link: 

# AQM parameters 
set minth 30	 
set maxth 0	 
set adaptive 1	;# 1 for Adaptive RED, 0 for plain RED 

# Traffic generation. 
set flows 0 	;# number of long-lived TCP flows 
set window 30	;# window for long-lived traffic 

# Plotting statistics. 
set opt(wrap) 100 ; # wrap plots? 
set opt(srcTrace) is ;# where to plot traffic 
set opt(dstTrace) bs2 ;# where to plot traffic 


#default downlink bandwidth in bps 
set bwDL(gsm)  9600 

#default downlink propagation delay in seconds 
set propDL(gsm)  .500 

set ns [new Simulator] 

set tf [open Mlab5.tr w] 
$ns trace-all $tf 

set nodes(is) [$ns node] 
set nodes(ms) [$ns node] 
set nodes(bs1) [$ns node] 
set nodes(bs2) [$ns node] 
set nodes(lp) [$ns node] 


proc cell_topo {} { 
  global ns nodes 
    $ns duplex-link $nodes(lp) $nodes(bs1) 3Mbps 10ms DropTail 
    $ns duplex-link $nodes(bs1) $nodes(ms) 1 1 RED 
    $ns duplex-link $nodes(ms) $nodes(bs2) 1 1 RED 
    $ns duplex-link $nodes(bs2) $nodes(is) 3Mbps 50ms DropTail 
    puts "GSM Cell Topology" 
    } 

 proc set_link_params {t} { 

 global ns nodes bwDL propDL 
 $ns bandwidth $nodes(bs1) $nodes(ms) $bwDL($t) duplex 
 $ns bandwidth $nodes(bs2) $nodes(ms) $bwDL($t) duplex 

 $ns delay $nodes(bs1) $nodes(ms) $propDL($t) duplex 
 $ns delay $nodes(bs2) $nodes(ms) $propDL($t) duplex 

 $ns queue-limit $nodes(bs1) $nodes(ms) 10 
 $ns queue-limit $nodes(bs2) $nodes(ms) 10 
 } 

  # RED and TCP parameter 
  Queue/RED set adaptive_ $adaptive 
  Queue/RED set thresh_ $minth 
  Queue/RED set maxthresh_ $maxth 
  Agent/TCP set window_ $window 

#Create topology 
  switch $type { 
   gsm {cell_topo} 
  } 

set_link_params $type 
$ns insert-delayer $nodes(ms) $nodes(bs1) [new Delayer] 
$ns insert-delayer $nodes(ms) $nodes(bs2) [new Delayer] 

  # Set up forward TCP connection 
  if {$flows == 0} { 
  set tcp1 [$ns create-connection TCP/Sack1 $nodes(is) TCPSink/Sack1 nodes(lp) 0] 
	set ftp1 [[set tcp1] attach-app FTP] 
        $ns at 0.8 "[set ftp1] start" 
	} 

        proc  stop {} { 
		  global nodes opt tf 
	 set wrap $opt(wrap) 
		  set sid [$nodes($opt(srcTrace)) id] 
		  set did [$nodes($opt(dstTrace)) id] 
		  
		  set a "Mlab5.tr" 
		  
		  set GETRC "/var/cn/ns-allinone-2.35/ns-2.35/bin/getrc" 
		  set RAW2XG "/var/cn/ns-allinone-2.35/ns-2.35/bin/raw2xg" 
		  
		  exec $GETRC -s $sid -d $did -f 0 Mlab5.tr | \
		  $RAW2XG -s 0.01 -m $wrap -r > plot.xgr 
		  
		  exec $GETRC -s $did -d $sid -f 0 Mlab5.tr | \
		  $RAW2XG -a -s 0.01 -m $wrap >> plot.xgr 
		  
		  exec xgraph -x time -y packets plot.xgr &
		  exit 0
		  } 
		  $ns at $stop "stop"
		  $ns run

Program Output