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$mmonitor trace-topo;# trace entire topology$mmonitor filter Common ptype_ $ptype(cbr) ;# filter on ptype_ in Common header$mmonitor filter IP dst_ $group;# AND filter on dst_ address in IP header$mmonitor print-trace;# begin dumping periodic traces to specified filesThe following sample output illustrates the output file format (time, count):0.16 00.17999999999999999 00.19999999999999998 00.21999999999999997 60.23999999999999996 110.25999999999999995 120.27999999999999997 1230.1.2 Protocol Specific configurationIn this section, we briefly illustrate the protocol specific configuration mechanisms for all the protocols implemented in ns.Centralized Multicast The centralized multicast is a sparse mode implementation of multicast similar to PIM-SM [9]. ARendezvous Point (RP) rooted shared tree is built for a multicast group. The actual sending of prune, join messages etc. toset up state at the nodes is not simulated. A centralized computation agent is used to compute the forwarding trees and setup multicast forwarding state, 〈S, G〉 at the relevant nodes as new receivers join a group. Data packets from the senders to agroup are unicast to the RP. Note that data packets from the senders are unicast to the RP even if there are no receivers for thegroup.The method of enabling centralised multicast routing in a simulation is:set mproto CtrMcastset mrthandle [$ns mrtproto $mproto];# set multicast protocolThe command procedure mrtproto{} returns a handle to the multicast protocol object. This handle can be used to controlthe RP and the boot-strap-router (BSR), switch tree-types for a particular group, from shared trees to source specific trees,and recompute multicast routes.$mrthandle set_c_rp $node0 $node1$mrthandle set_c_bsr $node0:0 $node1:1;# set the RPs;# set the BSR, specified as list of node:priority$mrthandle get_c_rp $node0 $group ;# get the current RP ???$mrthandle get_c_bsr $node0;# get the current BSR$mrthandle switch-treetype $group$mrthandle compute-mroutes;# to source specific or shared tree;# recompute routes. usually invoked automatically as neededNote that whenever network dynamics occur or unicast routing changes, compute-mroutes{} could be invoked to recomputethe multicast routes. The instantaneous re-computation feature of centralised algorithms may result in causalityviolations during the transient periods.263
Dense Mode The Dense Mode protocol (DM.tcl) is an implementation of a dense–mode–like protocol. Depending onthe value of DM class variable CacheMissMode it can run in one of two modes. If CacheMissMode is set to pimdm(default), PIM-DM-like forwarding rules will be used. Alternatively, CacheMissMode can be set to dvmrp (loosely basedon DVMRP [30]). The main difference between these two modes is that DVMRP maintains parent–child relationships amongnodes to reduce the number of links over which data packets are broadcast. The implementation works on point-to-point linksas well as LANs and adapts to the network dynamics (links going up and down).Any node that receives data for a particular group for which it has no downstream receivers, send a prune upstream. A prunemessage causes the upstream node to initiate prune state at that node. The prune state prevents that node from sending datafor that group downstream to the node that sent the original prune message while the state is active. The time duration forwhich a prune state is active is configured through the DM class variable, PruneTimeout. A typical DM configuration isshown below:DM set PruneTimeout 0.3DM set CacheMissMode dvmrp$ns mrtproto DM;# default 0.5 (sec);# default pimdmShared Tree Mode Simplified sparse mode ST.tcl is a version of a shared–tree multicast protocol. Class variable arrayRP_ indexed by group determines which node is the RP for a particular group. For example:ST set RP_($group) $node0$ns mrtproto STAt the time the multicast simulation is started, the protocol will create and install encapsulator objects at nodes that havemulticast senders, decapsulator objects at RPs and connect them. To join a group, a node sends a graft message towards theRP of the group. To leave a group, it sends a prune message. The protocol currently does not support dynamic changes andLANs.Bi-directional Shared Tree Mode BST.tcl is an experimental version of a bi–directional shared tree protocol. As inshared tree mode, RPs must be configured manually by using the class array RP_. The protocol currently does not supportdynamic changes and LANs.30.2 Internals of Multicast RoutingWe describe the internals in three parts: first the classes to implement and support multicast routing; second, the specificprotocol implementation details; and finally, provide a list of the variables that are used in the implementations.30.2.1 The classesThe main classes in the implementation are the class mrtObject and the class McastProtocol. There are alsoextensions to the base classes: Simulator, Node, Classifier, etc. We describe these classes and extensions in this subsection.The specific protocol implementations also use adjunct data structures for specific tasks, such as timer mechanisms by detaileddense mode, encapsulation/decapsulation agents for centralised multicast etc.; we defer the description of these objects to thesection on the description of the particular protocol itself.264
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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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Page 215 and 216: Part IIISupport214
Page 217 and 218: endenddocument pargvcPrint out argc
Page 219 and 220: 24.4.2 Memory Conservation TipsSome
Page 221 and 222: Chapter 25Mathematical SupportThe s
Page 223 and 224: set run [lindex $argv 0]}if {$run <
Page 225 and 226: }$sizeRNG next-substream# print the
Page 227 and 228: protected:RNG* rng_;};Classes deriv
Page 229 and 230: ns-random is implemented in ~ns/mis
Page 231 and 232: Chapter 26Trace and Monitoring Supp
Page 233 and 234: The monitor-queue function is const
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Page 239 and 240: PT_TORA,PT_DSR,PT_AODV,// insert ne
Page 241 and 242: The QueueMonitor class is not deriv
Page 243 and 244: $ns_ trace-all This is the command
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 263: $ns mrtproto ST;# specify shared tr
Page 267 and 268: and unique label (id). Thus, “inc
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Page 271 and 272: CtrMcastComp is the centralised mul
Page 273 and 274: $ns_ mrtproto This command specifi
Page 275 and 276: Chapter 31Network DynamicsThis chap
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Page 281 and 282: $ns_ rtmodel This command defines
Page 283 and 284: $ns set-address-format hierarchical
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Page 287 and 288: Chapter 33UDP Agents33.1 UDP Agents
Page 289 and 290: Chapter 34TCP AgentsThis section de
Page 291 and 292: set ns [new Simulator]set node1 [$n
Page 293 and 294: 34.2.1 The Base TCP SinkThe base TC
Page 295 and 296: Agent/TCP/FullTcp set dupseg_fix_ t
Page 297 and 298: 34.5 Tracing TCP DynamicsThe behavi
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Page 301 and 302: Figure 35.1: Example of a Multihome
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Page 307 and 308: $ns at 5.0 "finish"$ns run35.5.2 Mu
Page 309 and 310: Chapter 36Agent/SRMThis chapter des
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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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