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node or link will be up and down respectively. The default up and down interval values are 10s. and 1s.respectively. Any of these values can be specified as “−” to default to the original value.The following are example specifications of parameters to this model:0.8 1.0 1.0 ;# start at 0.8s., up/down = 1.0s., finish is default5.0 0.5 ;# start is default, up/down = 5.0s, 0.5s., finish is default- 0.7 ;# start, up interval are default, down = 0.7s., finish is default- - - 10 ;# start, up, down are default, finish at 10s.2. The deterministic on/off model is similar to the exponential model above, and takes four parameters: 〈[starttime], up interval, down interval, [finish time]〉. 〈start time〉 defaults to the start of the simulation, 〈finish time〉defaults to the end of the simulation. Only the interpretation of the up and down interval is different; 〈upinterval〉 and 〈down interval〉 specify the exact duration that the node or link will be up and down respectively.The default values for these parameters are: 〈start time〉 is 0.5s. from start of simulation, 〈up interval〉 is 2.0s.,〈down interval〉 is 1.0s., and 〈finish time〉 is the duration of the simulation.3. The trace driven model takes one parameter: the name of the trace file. The format of the input trace file isidentical to that output by the dynamics trace modules, viz., v 〈time〉 link-〈operation〉〈node1〉〈node2〉. Lines that do not correspond to the node or link specified are ignored.v 0.8123 link-up 3 5v 3.5124 link-down 3 54. The manual one-shot model takes two parameters: the operation to be performed, and the time that it is to beperformed.• The rest of the arguments to the rtmodel{} procedure define the node or link that the model will be applied to.If only one node is specified, it is assumed that the node will fail. This is modeled by making the links incidenton the node fail. If two nodes are specified, then the command assumes that the two are adjacent to each other,and the model is applied to the link incident on the two nodes. If more than two nodes are specified, only the firstis considered, the subsequent arguments are ignored.• instance variable, traceAllFile_ is set.The command returns the handle to the model that was created in this call.Internally, rtmodel{} stores the list of route models created in the class Simulator instance variable, rtModel_.— The instance procedure rtmodel-delete{} takes the handle of a route model as argument, removes it from thertModel_ list, and deletes the route model.— The instance procedure rtmodel-at{} is a special interface to the Manual model of network dynamics.The command takes the time, operation, and node or link as arguments, and applies the operation to the node or link atthe specified time. Example uses of this command are:$ns rtmodel-at 3.5 up $n0$ns rtmodel-at 3.9 up $n(3) $n(5)$ns rtmodel-at 40 down $n4Finally, the instance procedure trace-dynamics{} of the class rtModel enables tracing of the dynamics effected by thismodel. It is used as:set fh [open "dyn.tr" w]$rtmodel1 trace-dynamics $fh$rtmodel2 trace-dynamics $fh$rtmodel1 trace-dynamics stdoutIn this example, $rtmodel1 writes out trace entries to both dyn.tr and stdout; $rtmodel2 only writes out trace entries todyn.tr. A typical sequence of trace entries written out by either model might be:275
v 0.8123 link-up 3 5v 0.8123 link-up 5 3v 3.5124 link-down 3 5v 3.5124 link-down 5 3These lines above indicate that Link 〈3, 5〉 failed at 0.8123s., and recovered at time 3.5124s.31.2 The Internal ArchitectureEach model of network dynamics is implemented as a separate class, derived from the base class rtModel. We beginby describing the base class rtModel and the derived classes (Section 31.2.1). The network dynamics models use an internalqueuing structure to ensure that simultaneous events are correctly handled, the class rtQueue. The next subsection (Section31.2.2) describes the internals of this structure. Finally, we describe the extensions to the existing classes (Section 31.3.1):the Node, Link, and others.31.2.1 The class rtModelTo use a new route model, the routine rtmodel{} creates an instance of the appropriate type, defines the node or link thatthe model will operate upon, configures the model, and possibly enables tracing; The individual instance procedures thataccomplish this in pieces are:The constructor for the base class stores a reference to the Simulator in its instance variable, ns_. It also initializes thestartTime_ and finishTime_ from the class variables of the same name.The instance procedure set-elements identifies the node or link that the model will operate upon. The command storestwo arrays: links_, of the links that the model will act upon; nodes_, of the incident nodes that will be affected bythe link failure or recovery caused by the model.The default procedure in the base class to set the model configuration parameters is set-parms. It assumes a well definedstart time, up interval, down interval, and a finish time, and sets up configuration parameters for some class of models.It stores these values in the instance variables: startTime_, upInterval_, downInterval_, finishTime_.The exponential and deterministic models use this default routine, the trace based and manual models define their ownprocedures.The instance procedure trace{} enables trace-dynamics{} on each of the links that it affects. Additional detailson trace-dynamics{} is discussed in the section on extensions to the class Link (Section 31.3.1).The next sequence of configuration steps are taken just prior to the start of the simulator. ns invokes rtmodel-configure{}just before starting the simulation. This instance procedure first acquires an instance of the class rtQueue, and then invokesconfigure{} for each route model in its list, rtModel_.The instance procedure configure{} makes each link that is is applied to dynamic; this is the set of links stored inits instance variable array, links_. Then the procedure schedules its first event.The default instance procedure set-first-event{} schedules the first event to take all the links “down” at$startTime_ + upInterval_. Individual types of route models derived from this base class should redefine tihsfunction.276
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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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3.5 Class TclClassThis compiled cla
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class Packet {......static int hdrl
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The actual arguments passed by the
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class TclClass (Section 3.5) define
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Chapter 4The Class SimulatorThe ove
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4.2.2 the heap schedulerThe heap sc
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4.4 Commands at a glanceSynopsis:ns
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$ns_ dumpqCommand for dumping event
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NODEPortClassifierAgentAgentAddrCla
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The Node instance variable, entry_,
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The default values for all the abov
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The classify() method is pure virtu
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};The class imposes no direct seman
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flow-specific queuing disciplines a
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5.5 Routing Module and Classifier O
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Module NameRtModule/BaseRtModule/Mc
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$node neighborsThis returns the lis
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Linkhead_enqT_queue_ deqT_ link_ tt
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6.2 ConnectorsConnectors, unlink cl
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$ns_ link-lossmodel This function
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Chapter 7Queue Management and Packe
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}}}void Queue::resume(){Packet* p =
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7.3 Different types of Queue object
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maxidle_ is the maximum amount of t
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dst_ The destination address of pac
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7.5.2 ConfigurationRunning a JoBS s
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mean_pkt_size_ Used to set the expe
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Demarker objects$q trace-file This
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The recv() method overrides the bas
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9.2 ImplementationThe procedures an
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Average sending rateTSW window leng
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The following command adds an entry
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$qCE configQ 0 1 10 20 0.10Note tha
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Chapter 10AgentsAgents represent en
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CtrMcast/EncapCtrMcast/DecapMessage
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}bind("windowOption_", &wnd_option_
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hdr_flags* nf = (hdr_flags*)npkt->a
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public:ECHO_Timer(ECHO_Agent *a) :
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10.6.4 Using the agent through OTcl
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State Variables are:dupacks_ Number
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$agent attach-tbf Attaches a token
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(void)Scheduler::instance().schedul
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* outstanding, cancel it.*/void Tcp
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Chapter 12Packet Headers and Format
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method is now obsolete; its usage i
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Packethdrsize_next_bits()points to
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the system’s memory allocator. In
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}incr hdrlen_ $incrreturn $baseFrom
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Chapter 13Error ModelThis chapter d
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SimpleLink::errormodule argsSimulat
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This is a simple example of how to
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Higher LayersNode 1Node 2. . .Node
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};void recv(Packet* p, Handler*);vi
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and the frame type. It then passes
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$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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Page 245 and 246: Chapter 27Test Suite SupportThe ns
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Page 249 and 250: Example: To enable debugging in Que
Page 251 and 252: Chapter 29Unicast RoutingThis secti
Page 253 and 254: Asymmetric Routing Asymmetric routi
Page 255 and 256: class RouteLogic This class defines
Page 257 and 258: — The procedure init-all{} is a g
Page 259 and 260: Global Actions Once the detailed ac
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Page 281 and 282: $ns_ rtmodel This command defines
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37.3 Architecture of the PLM Protoc
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We add in void PLMLossMonitor::recv
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Part VIApplication330
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Traffic generatorsApplication/Traff
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• recv(int nbytes)—Announces th
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1. EXPOO_Traffic—generates traffi
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set src [new Agent/UDP]set sink [ne
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Application FTP FTP objects produce
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send_data(ADU)Application(HttpApp,
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39.1.4 Transmitting user data over
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and teardown of connections. Only O
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TclObjectPagePoolPagePool/CompMathP
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PagePool/ProxyTrace takes these two
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}int id_; // object IDWebTrafSessio
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An Http/Server object waits for inc
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set tmp [new RandomVariable/Exponen
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Object Type Event Type Explaination
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Chapter 40Worm ModelIn this chapter
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$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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