Hi Dan,
still getting dropped ACKS from node1 with column4=IFQ, indicating
dropped because of queue??? Is tis some sort of NS error? Am I correct in
thinking that this isn't a feature of the network/protocol and it should be
ignored in my analysis?
L
>From: Dan Dechene <[EMAIL PROTECTED]>
>To: 'Lars Lars' <[EMAIL PROTECTED]>
>Subject: RE: [ns] TCP over 802.11b dropping ACKs
>Date: Tue, 19 Dec 2006 18:06:43 -0500
>
>This shouldn't happen. However try:
>
>Queue/DropTail/PriQueue as interface queue type instead of Queue/DropTail
>
>Dan Dechene, B.Eng.
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
>Of Lars Lars
>Sent: Tuesday, December 19, 2006 5:29 PM
>To: [email protected]
>Subject: [ns] TCP over 802.11b dropping ACKs
>
>
>Hi,
> I've a 2-node(static) wireless link(802.11b). The tracefile is showing
>me
>that ACK packets being sent from node1 to node0 are being dropped(which is
>OK), however, the fourth column in the tracefile is IFQ which implies that
>these packets are being dropped due to the ifq. How can this be? PAckets on
>the return path don't enter a queue at any point surely??? My simulation is
>transferring FTP data from node0 to node1. The TCP agent is on node0 and
>the
>
>sink is on node1. below is a section from my trace file. What does IFQ mean
>in column 4. If (as I understand it) this means that these packets are
>being
>
>dropped by the ifq, then why is there an IFQ on the return path as all the
>traffic is going from node0 to node1? (My simulation script is below also).
>
>Thanks
>
>L
>
>D 30.32288741 _0_ IFQ --- 15598 tcp 1084 [0
>D 30.34824777 _0_ IFQ --- 15611 tcp 1084 [0
>D 30.62936723 _1_ IFQ --- 15759 ack 60 [0
>D 30.6869282 _1_ IFQ --- 15792 ack 60 [0
>D 30.70534317 _1_ IFQ --- 15801 ack 60 [0
>D 30.72629153 _1_ IFQ --- 15813 ack 60 [0
>
>
>set val(chan) Channel/WirelessChannel ;# channel type
>set val(prop) Propagation/TwoRayGround ;# radio-propagation
>model
>set val(netif) Phy/WirelessPhy ;# network interface
>type
>set val(mac) Mac/802_11 ;# MAC type
> Mac/802_11 set dataRate_ 11Mb ;# Data Rate
>11 Mbps
> Mac/802_11 set basicRate_ 1Mb ;# Basic
>Rate 1 Mbps
># Mac/802_11 set RTSThreshold_ 3000 ;# Turn off
>RTS / CTS
> Mac/802_11 set SlotTime_ 0.000020 ;# 20us
> Mac/802_11 set sifs_ 0.000010 ;# 10us
> Mac/802_11 set PreambleLenght_ 144 ;# 144 bits
> Mac/802_11 set PLCPHeaderLength_ 48 ;# 48 bits
> Mac/802_11 set PLCPDataRate_ 1Mb ;# 1Mbps
>
>set val(ifq) Queue/DropTail ;# interface queue type/PriQueue
>set val(ll) LL ;# link layer type
>set val(ant) Antenna/OmniAntenna ;# antenna model
>set val(ifqlen) 10 ;# max packet in ifq
>set val(nn) 2 ;# number of mobilenodes
>set val(rp) DSDV ;# routing protocol DSDV
>
>set ns [new Simulator]
>
>$ns color 0 blue
>$ns color 1 red
>
># set up topography object
>set topo [new Topography]
>$topo load_flatgrid 400 200
>
>#Open the trace file
>set tf [open out.tr w]
>$ns trace-all $tf
>
>#Open the nam trace file
>set nf [open out.nam w]
>$ns namtrace-all-wireless $nf 400 200
>
># Create God
>create-god $val(nn)
>
>Agent/DSDV set perup_ 15000000 ;# ~ infinite periodic update
>
> $ns node-config -adhocRouting $val(rp) \
> -llType $val(ll) \
> -macType $val(mac) \
> -ifqType $val(ifq) \
> -ifqLen $val(ifqlen) \
> -antType $val(ant) \
> -propType $val(prop) \
> -phyType $val(netif) \
> -channelType $val(chan) \
> -topoInstance $topo \
> -agentTrace OFF \
> -routerTrace OFF \
> -macTrace ON \
> -movementTrace OFF
>
>
>
># Create and configure nodes
>set nodeA [$ns node]
>$nodeA random-motion 0
>$nodeA set X_ 100.0
>$nodeA set Y_ 100.0
>$nodeA set Z_ 0.0
>
>set nodeB [$ns node]
>$nodeB random-motion 0
>$nodeB set X_ 300.0
>$nodeB set Y_ 100.0
>$nodeB set Z_ 0.0
>
>$ns at 0.0 "$nodeA setdest 100.0 100.0 0.0"
>$ns at 0.0 "$nodeB setdest 300.0 100.0 0.0"
>
>
># Setup TCP Connection
>set tcpA [new Agent/TCP]
>$ns attach-agent $nodeA $tcpA
>$tcpA set packetSize_ 1024
>set tcpSinkB [new Agent/TCPSink]
>$ns attach-agent $nodeB $tcpSinkB
>
>$ns connect $tcpA $tcpSinkB
>
># Setup FTP over TCP Connection
>set ftpA [new Application/FTP]
>$ftpA attach-agent $tcpA
>$ftpA set type_ FTP
>
># Schedule simulation events
>
>$ns at 1.0 "$ftpA start"
>$ns at 31.0 "$ftpA stop"
>$ns at 31.0000001 "stop"
>$ns at 31.0000002 "puts \"NS EXITING...\" ; $ns halt"
>
>proc stop {} {
> global ns tf nf
> $ns flush-trace
> close $nf
> close $tf
> exit 0
>}
>
>puts "Starting Simulation..."
>$ns run
>
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