video-scenario.tcl

对IEEE 802.11e里的分布式信道接入算法EDCA进行改进

#
# A wireless lan scenario with video/cbr traffic over udp
#
#

# defaults
set num_nodes 6					;# number of mobilenodes in the scenario
set blocking_factor 1				;# default blocking factor
set transport TCP				;# default transport protocol

proc create_scenario { } {
	global ns_ node_ AP_ title_ mode
	global blocking_factor transport
	global pcf_period pcf_duration

	set pcf_period [expr 2 * $blocking_factor]ms
	set pcf_duration ${blocking_factor}ms

	##########################################################
	# Setup Video flows V1 and V2
	# source for V1 and V2 is the AP

	# period/pktsize of Video Streams based on the blocking factor
	set period	[expr 2 * $blocking_factor]ms
	set pktsize	[expr 2048 * $blocking_factor]

	# Flow V1

	set V1		[new Application/Traffic/CBR]
	set V1_src	[new Agent/UDP]
	set V1_sink	[new Agent/UDP]

	$V1 set		random_ 0
	$V1 set		packetSize_ $pktsize
	$V1 set		interval_ $period
	$V1_src set	packetSize_ 2048
	$V1_src set	class_ 2
	$V1_src set	prio_ 0

	$ns_ attach-agent $AP_ $V1_src
	$ns_ attach-agent $node_(1) $V1_sink
	$ns_ connect $V1_src $V1_sink
	$V1 attach-agent $V1_src
	puts "V1 flows from AP to Node1"

	# Flow V2

	set V2		[new Application/Traffic/CBR]
	set V2_sink	[new Agent/UDP]
	set V2_src	[new Agent/UDP]

	$V2 set		random_ 0
	$V2 set		packetSize_ $pktsize
	$V2 set		interval_ $period
	$V2_src set	packetSize_ 2048
	$V2_src set	class_ 3
	$V2_src set	prio_ 0

	$ns_ attach-agent $AP_ $V2_src
	$ns_ attach-agent $node_(2) $V2_sink
	$ns_ connect $V2_src $V2_sink
	$V2 attach-agent $V2_src
	puts "V2 flows from AP to Node2"


	##########################################################
	# Setup Background flow B1
	# B1 flows from Node3 to Node4 via the AP
	# B1 is a FTP stream with 1500 byte MTUs

	set B1		[new Application/FTP]
	if {$transport == "TCP"} {
		set B1_src	[new Agent/TCP]
		set B1_sink	[new Agent/TCPSink/DelAck]
		$B1_src		set syn_ 1
	} elseif {$transport == "UDP"} {
		set B1_src	[new Agent/UDP]
		set B1_sink	[new Agent/UDP]
	} else {
		puts "Bad transport protocol"
		exit
	}

	$B1_src		set packetSize_ 1500
	$B1_src		set class_ 4
	$B1_src		set prio_ 1

	$ns_ attach-agent $node_(3) $B1_src
	$ns_ attach-agent $node_(4) $B1_sink
	$ns_ connect $B1_src $B1_sink
	$B1 attach-agent $B1_src
	puts "B1 flows from Node3 to Node4 over $transport"


	##########################################################
	# Setup Background flow B2
	# B2 flows from Node4 to Node5 via the AP
	# B2 is a FTP stream with 256 byte MTUs

	set B2		[new Application/FTP]

	if {$transport == "TCP"} {
		set B2_src	[new Agent/TCP]
		set B2_sink	[new Agent/TCPSink/DelAck]
		$B2_src		set syn_ 1
	} elseif {$transport == "UDP"} {
		set B2_src	[new Agent/UDP]
		set B2_sink	[new Agent/UDP]
	} else {
		puts "Bad transport protocol"
		exit
	}

	$B2_src		set packetSize_ 256
	$B2_src		set class_ 5
	$B2_src		set prio_ 1

	$ns_ attach-agent $node_(4) $B2_src
	$ns_ attach-agent $node_(5) $B2_sink
	$ns_ connect $B2_src $B2_sink
	$B2 attach-agent $B2_src
	puts "B2 flows from Node4 to Node5 over $transport"


	##########################################################
	# Start time, nature of simulation

	if {$mode == "PCF"} {
		set access PCF_NAV
	} else {
		set access $mode
		if {[PLevels set plevels_] > 1} {
			set access VDCF
		}
		$ns_ at 3.0	"$V1 start"
		$ns_ at 6.0	"$V2 start"
	}
	$ns_ at 9.0	"$B1 start"
	$ns_ at 12.01	"$B2 start"

	set phy_bw [Mac/802_11 set bandwidth_]
	set retries [MAC_MIB set ShortRetryLimit_]
	set pqlim [Queue/DropTail set pqlim_]
	set title_ "set title \"VIDEO PHY($phy_bw) $access RETRIES($retries) IFQ($pqlim) MTU(2K) PERIOD($period)\""
}