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Marking the trafficMarking the traffic is handled by Marker objects. Markers are FIFO queues that set the class index of each packet. To ensureaccuracy of the simulations, it is best to configure these queues to have a very large buffer, so that no packets are dropped inthe Marker. Demarkers are used to gather end-to-end delay statistics.$ns_ simplex-link $source $router(1) $bw $delay Marker;# set-up marker$ns_ queue-limit $source $router(1) [expr $buff*10];# Select huge buffers for markers$ns_ queue-limit $router(1) $source [expr $buff*10];# to avoid traffic dropsset q [$ns_ get-queue $source $router(1)];#in the marker$q marker_type 2 ;# Statistical marker$q marker_frc 0.1 0.2 0.3 0.4 ;# 10% Class 1, 20% Class 2, 30% Class 3, 40% Class 4.$ns_ simplex-link $router(2) $sink $bw $delay Demarker;# set-up demarker$ns_ queue-limit $router(2) $sink [expr $buff*10]$q trace-file e2e ;# trace end-to-end delays to file e2eThe remaining steps (attaching agents and traffic generators or applications to the nodes) are explained in Chapters 10 and38, and are handled as usual. We refer to these chapters and the example scripts provided with your ns distribution.7.5.3 TracingTracing in JoBS is handled internally, by the scheduler. Each JoBS queue can generate a trace file containing the followinginformation. Each line of the tracefile consists of 17 columns. The first column is the simulation time, columns 2 to 5 representthe loss rates over the current busy period for classes 1 to 4, columns 6 to 9 represent the delays for each class (average overa 0.5 seconds sliding window), columns 10 to 13 represent the average service rates allocated to each class over the last 0.5seconds, and columns 14 to 17 represent the instantaneous queue length in packets. Additionally, Demarkers can be used totrace end-to-end delays.7.5.4 VariablesThis section summarizes the variables that are used by JoBS, Marker and Demarker objects.JoBS objectstrace_hop_ Can be true or false. If set to true, per-hop, per-class metrics will be traced. (Trace files have then to be specified,using trace-file .) Defaults to false.drop_front_ Can be true or false. If set to true, traffic will be dropped from the front of the queue. Defaults to false(drop-tail).adc_resolution_type_ Can be 0 or 1. If set to 0, traffic will be dropped from classes that have an ADC if the ADC cannotbe met by adjusting the service rates. If set to 1, traffic will be dropped from all classes. A resolution mode set to 1 istherefore fairer, in the sense that the pain is shared by all classes, but can lead to more deadline violations. Defaults to0.shared_buffer_ Can be 0 or 1. If set to 0, all classes use a separate per-class buffer (which is required if only rate guaranteesare to provided). All per-class buffers have the same size. If set to 1, all classes share the same buffer (which is requiredif loss differentiation is to be provided). Defaults to 1.81
mean_pkt_size_ Used to set the expected mean packet size of packets arriving at a JoBS link. Setting this variable is requiredto ensure proper delay differentiation.Marker objectsmarker_arrvs1_ Number of Class-1 packets to have entered a Marker link.marker_arrvs2_ Number of Class-2 packets to have entered a Marker link.marker_arrvs3_ Number of Class-3 packets to have entered a Marker link.marker_arrvs4_ Number of Class-4 packets to have entered a Marker link.Demarker objectsdemarker_arrvs1_ Number of Class-1 packets to have entered a Demarker link.demarker_arrvs2_ Number of Class-2 packets to have entered a Demarker link.demarker_arrvs3_ Number of Class-3 packets to have entered a Demarker link.demarker_arrvs4_ Number of Class-4 packets to have entered a Demarker link.7.5.5 Commands at a glanceThe following is a list of commands used to configure the JoBS, Marker and Demarker objects.JoBS objectsset q [new Queue/JoBS]This creates an instance of the JoBS queue.$q init-rdcs This assigns the RDCs for the four JoBS classes. For instance, using a value of 4 for k2 means that Class-3 delays will beroughly equal to four times Class-2 delays. A value of -1 indicates that the class is not concerned by RDCs.Important Note: Since RDCs bound two classes, one would expect only three parameters to be passed (k1, k2, and k3, sincek4 theoretically binds Classes 4 and 5, and Class 5 does not exist). However, in this prototype implementation, it isimperative to specify a value different from 0 and -1 to k4 if Class 4 is to be concerned by RDCs.Examples: $q init-rdcs -1 2 1 -1 specifies that classes 2 and 3 are bound by a delay differentiation factor of 2, $qinit-rdcs 4 4 4 4 specifies that all classes are bound by a delay differentiation factor of 4 and is equivalent to $qinit-rdcs 4 4 4 1, since the last coefficient is only used to specify that Class 4 is to be bound by proportionaldifferentiation.$q init-rlcs This assigns the RLCs for the four JoBS classes. For instance, using a value of 3 for k1 means that Class-2 loss rates will beroughly equal to four times Class-2 loss rates. A value of -1 indicates that the class is not concerned by RLCs. As withRDCs, each RLC binds two classes, thus, one would expect only three parameters to be passed (k’1, k’2, and k’3, since k’482
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18 Radio Propagation Models 17718.1
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30 Multicast Routing 25130.1 Multic
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38.2.5 An example . . . . . . . . .
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X Other 40347 Educational use of NS
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# so, we lied. now, we define the t
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Chapter 2Undocumented FacilitiesNs
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Part IInterface to the Interpreter1
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• if you can do what you want by
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• tcl.result(const char* s)Pass t
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By convention in ns, the class Agen
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$object set bwvar 1500kb$object set
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For a C++ variable to be traceable,
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Page 33 and 34: class Packet {......static int hdrl
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Page 37 and 38: class TclClass (Section 3.5) define
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Page 41 and 42: 4.2.2 the heap schedulerThe heap sc
Page 43 and 44: 4.4 Commands at a glanceSynopsis:ns
Page 45 and 46: $ns_ dumpqCommand for dumping event
Page 47 and 48: NODEPortClassifierAgentAgentAddrCla
Page 49 and 50: The Node instance variable, entry_,
Page 51 and 52: The default values for all the abov
Page 53 and 54: The classify() method is pure virtu
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Page 57 and 58: flow-specific queuing disciplines a
Page 59 and 60: 5.5 Routing Module and Classifier O
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Page 63 and 64: $node neighborsThis returns the lis
Page 65 and 66: Linkhead_enqT_queue_ deqT_ link_ tt
Page 67 and 68: 6.2 ConnectorsConnectors, unlink cl
Page 69 and 70: $ns_ link-lossmodel This function
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Page 73 and 74: }}}void Queue::resume(){Packet* p =
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Page 79 and 80: dst_ The destination address of pac
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Page 85 and 86: Demarker objects$q trace-file This
Page 87 and 88: The recv() method overrides the bas
Page 89 and 90: 9.2 ImplementationThe procedures an
Page 91 and 92: Average sending rateTSW window leng
Page 93 and 94: The following command adds an entry
Page 95 and 96: $qCE configQ 0 1 10 20 0.10Note tha
Page 97 and 98: Chapter 10AgentsAgents represent en
Page 99 and 100: CtrMcast/EncapCtrMcast/DecapMessage
Page 101 and 102: }bind("windowOption_", &wnd_option_
Page 103 and 104: hdr_flags* nf = (hdr_flags*)npkt->a
Page 105 and 106: public:ECHO_Timer(ECHO_Agent *a) :
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Page 109 and 110: State Variables are:dupacks_ Number
Page 111 and 112: $agent attach-tbf Attaches a token
Page 113 and 114: (void)Scheduler::instance().schedul
Page 115 and 116: * outstanding, cancel it.*/void Tcp
Page 117 and 118: Chapter 12Packet Headers and Format
Page 119 and 120: method is now obsolete; its usage i
Page 121 and 122: Packethdrsize_next_bits()points to
Page 123 and 124: the system’s memory allocator. In
Page 125 and 126: }incr hdrlen_ $incrreturn $baseFrom
Page 127 and 128: Chapter 13Error ModelThis chapter d
Page 129 and 130: SimpleLink::errormodule argsSimulat
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Higher LayersNode 1Node 2. . .Node
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};void recv(Packet* p, Handler*);vi
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and the frame type. It then passes
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$ll_ set delay_ $delay$ll_ set band
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14.10 Commands at a glanceThe follo
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15.2.1 Default Hierarchical Setting
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Chapter 16Mobile Networking in nsTh
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entry_addrdemuxIP addressdefaulttar
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16.1.2 Creating Node movementsThe m
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set netif $netif_($t)set mac $mac_(
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the hardware address of a packet’
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destined to itself to the port dmux
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switch(ch->ptype()) {case PT_MAC:br
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16.1.7 Revised format for wireless
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Packet info at "Application level"
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The main problem facing the wired-c
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target_target_encapsulatorreg_agent
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why: This avoids header clashes bet
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This command is used to create a Go
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Chapter 17Satellite Networking in n
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in counter-rotating planes (where t
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• Position/Sat/Geo A geostationar
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$ns add-isl $ltype $node1 $node2 $b
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$satrouteobject_ compute_routeswher
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This will add an error model to the
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lh_firstnameobj‘‘name’’ is
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from routing agentto Node->entrySat
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$satnode add-isl This method c
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set prop [new Propagation/FreeSpace
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18.3.2 Using shadowing modelBefore
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Chapter 19Energy Model in nsEnergy
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Chapter 20Directed DiffusionThe dir
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However if we have a large and dens
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yr application in the ns context. T
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value of opt(pre-stop) is usually t
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21.2 Implementation of XCP in NSIn
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the persistent queue length in the
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Thruput2 0.054024 60000residue_pos_
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Chapter 22DelayBox: Per-Flow Delay
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$ns attach-agent $n_sink $sink# mak
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Chapter 23Changes made to the IEEE
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Part IIISupport214
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endenddocument pargvcPrint out argc
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24.4.2 Memory Conservation TipsSome
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Chapter 25Mathematical SupportThe s
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set run [lindex $argv 0]}if {$run <
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}$sizeRNG next-substream# print the
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protected:RNG* rng_;};Classes deriv
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ns-random is implemented in ~ns/mis
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Chapter 26Trace and Monitoring Supp
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The monitor-queue function is const
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also used to accumulate packet drop
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}name,th->size(),flags,iph->flowid(
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PT_TORA,PT_DSR,PT_AODV,// insert ne
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The QueueMonitor class is not deriv
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$ns_ trace-all This is the command
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Chapter 27Test Suite SupportThe ns
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... ...}$ns_ at $opt(stop).1 "$self
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Example: To enable debugging in Que
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Chapter 29Unicast RoutingThis secti
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Asymmetric Routing Asymmetric routi
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class RouteLogic This class defines
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— The procedure init-all{} is a g
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Global Actions Once the detailed ac
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This dumps next hop information in
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$ns mrtproto ST;# specify shared tr
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Dense Mode The Dense Mode protocol
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and unique label (id). Thus, “inc
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add-iif{ifid link},add-oif{link if}
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CtrMcastComp is the centralised mul
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$ns_ mrtproto This command specifi
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Chapter 31Network DynamicsThis chap
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v 0.8123 link-up 3 5v 0.8123 link-u
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The first argument is the time at w
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$ns_ rtmodel This command defines
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$ns set-address-format hierarchical
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32.4 Hierarchical Routing with Sess
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Chapter 33UDP Agents33.1 UDP Agents
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Chapter 34TCP AgentsThis section de
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set ns [new Simulator]set node1 [$n
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34.2.1 The Base TCP SinkThe base TC
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Agent/TCP/FullTcp set dupseg_fix_ t
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34.5 Tracing TCP DynamicsThe behavi
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Chapter 35SCTP AgentsThis chapter d
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Figure 35.1: Example of a Multihome
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Note: the actual value of these tra
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1.526624 1 4 sctp 1500 -------D 0 1
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$ns at 5.0 "finish"$ns run35.5.2 Mu
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Chapter 36Agent/SRMThis chapter des
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36.1.2 Other Configuration Paramete
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3.6274 n 0 m r 1 type repair servi
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3.6029 n 3 m r 2 Q NTIMER at 3.730
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36.4 Loss Detection—The Class SRM
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same packet. The repair objet does
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}hdr_asrm* seh = (hdr_asrm*) p->acc
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set grp [Node allocaddr]$srm set ds
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#set up the multicast routingDM set
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37.3 Architecture of the PLM Protoc
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We add in void PLMLossMonitor::recv
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Part VIApplication330
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Traffic generatorsApplication/Traff
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• recv(int nbytes)—Announces th
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1. EXPOO_Traffic—generates traffi
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set src [new Agent/UDP]set sink [ne
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Application FTP FTP objects produce
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send_data(ADU)Application(HttpApp,
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39.1.4 Transmitting user data over
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and teardown of connections. Only O
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TclObjectPagePoolPagePool/CompMathP
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PagePool/ProxyTrace takes these two
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}int id_; // object IDWebTrafSessio
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An Http/Server object waits for inc
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set tmp [new RandomVariable/Exponen
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Object Type Event Type Explaination
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Chapter 40Worm ModelIn this chapter
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$w local-p 0.5Following are some co
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(nsnode) clientcloudPackM ime(nsnod
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HTTP responsesclients servers Delay
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41.5 Commands at a GlanceThe follow
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• HTTP response size (bytes)• s
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Chapter 42Session-level Packet Dist
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42.1.2 Inserting a Loss ModuleWhen
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Delay and Loss Modules Each receive
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Chapter 43Asim: approximate analyti
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set n(1) [$ns node]set link(0:1) [$
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Part VIIIEmulation382
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When using the emulation mode, a sp
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set intf [$pf1 open readonly]puts "
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puts "install nets into taps..."$a0
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Chapter 45Nam45.1 IntroductionNam i
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• Button 6 (Chevron logo) - Close
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Second, when dealing with randomly
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dst_portaddr,seqno,flags,sname);A n
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• up• down• right• left•
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46.1.7 Agent TracingAgent trace eve
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v -t 1.0 -e node_tclscript 2 "Echo
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If nam ever gets to the end of an e
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l :link-t time-s source id-d des
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E :D :P :a :session enqueue-t time
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v :V :N :W :g :A :c :q :execute tcl
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$ns duplex-link-op orient right$ns
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Chapter 47Educational use of NS and
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Bibliography[1] C. Alaettinoğlu, A
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