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a starting position. The information regarding number of hops between the nodes is fed to the central object "GOD" (XXXbut why/where is this information used??-answer awaited from CMU.) Next each node is a speed and a direction to move to.The generator for creating node movement files are to be found under ~ns/indep-utils/cmu-scen-gen/setdest/ directory. Compilethe files under setdest to create an executable. run setdest with arguments in the following way:./setdest -n -p -s -t -x -y > /Note that the index used for nodes now start from 0 instead of 1 as was in the original CMU version, to match with ns’stradition of assigning node indices from 0.Generating traffic pattern filesThe examples for traffic patterns may be found in ~ns/tcl/mobility/scene/cbr-50-{10-4-512, 20-4-512}.The traffic generator is located under ~ns/indep-utils/cmu-scen-gen/ and are called cbrgen.tcl and tcpgen.tcl. They may beused for generating CBR and TCP connections respectively.To create CBR connecions, runns cbrgen.tcl [-type cbr|tcp] [-nn nodes] [-seed seed][-mc connections] [-rate rate]To create TCP connections, runns tcpgen.tcl [-nn nodes] [-seed seed]You will need to pipe the outputs from above to a cbr-* or a tcp-* file.16.2 Extensions made to CMU’s wireless modelAs mentioned earlier, the original CMU wireless model allows simulation of wireless LANs and ad-hoc networks. Howeverin order to use the wireless model for simulations using both wired and wireless nodes we had to add certain extensions tocmu model. We call this wired-cum-wireless feature. Also SUN’s MobileIP (implemented for wired nodes) was integratedinto the wireless model allowing mobileIP to run over wireless mobilenodes. The following two subsections describe thesetwo extensions to the wireless model in ns.16.2.1 wired-cum-wireless scenariosThe mobilenodes described so far mainly supports simulation of multi-hop ad-hoc networks or wireless LANs. But what ifwe need to simulate a topology of multiple wireless LANs connected through wired nodes, or may need to run mobileIP ontop of these wireless nodes? The extensions made to the CMU wireless model allows us to do that.161
The main problem facing the wired-cum-wireless scenario was the issue of routing. In ns, routing information is generatedbased on the connectivity of the topology, i.e how nodes are connected to one another through Links. Mobilenodes on theother hand have no concept of links. They route packets among themselves, within the wireless topology, using their routingprotocol. so how would packets be exchanged between these two types of nodes?So a node called BaseStationNode is created which plays the role of a gateway for the wired and wireless domains.The BaseStationNode is essentially a hybrid between a Hierarchical node 1 (HierNode) and a MobileNode. Thebasestation node is responsible for delivering packets into and out of the wireless domain. In order to achieve this we needHierarchical routing.Each wireless domain along with its base-station would have an unique domain address assigned to them. All packets destinedto a wireless node would reach the base-station attached to the domain of that wireless node, who would eventually hand thepacket over to the destination (mobilenode). And mobilenodes route packets, destined to outside their (wireless) domain, totheir base-station node. The base-station knows how to forward these packets towards the (wired) destination. The schematicof a BaseStationNode is shown in Figure 16.3.The mobilenodes in wired-cum-wireless scenario are required to support hierarchical addressing/routing. Thus the MobileNodelooks exactly like the BaseStationNode. The SRNode, however, simply needs to have its own hier-address since it doesnot require any address demuxes and thus is not required to support hier routing 2 .The DSDV agent on having to forward a packet checks to see if the destination is outside its (wireless) subnet. If so, it triesto forward the packet to its base-station node. In case no route to base-station is found the packet is dropped. Otherwisethe packet is forwarded to the next_hop towards the base-station. Which is then routed towards the wired network by basestation’sclassifiers.The DSR agent, on receiving a pkt destined outside its subnet, sends out a route-query for its base-station in case the route tobase-station is not known. The data pkt is temporarily cached while it waits to hear route replies from base-station. On gettinga reply the packet is provided with routing information in its header and send away towards the base-station. The base-stationaddress demuxes routes it correctly toward the wired network.The example script for a wired-cum-wireless simulation can be found at ~ns/tcl/ex/wired-cum-wireless-sim.tcl. The methodsfor wired-cum-wireless implementations are defined in ~ns/tcl/lib/ns-bsnode.tcl, ~ns/tcl/mobility/{com.tcl,dsr.tcl, dsdv.tcl},~ns/dsdv/dsdv.{cc,h} and ~ns/dsr/dsragent.{cc,h}.16.2.2 MobileIPThe wired-cum-wireless extensions for the wireless model paved the path for supporting wireless MobileIP in ns. SunMicrosystem’s (Charlie Perkins et al) MobileIP model was based on ns’s wired model (consisting of Node’s and Link’s)and thus didnot use CMU’s mobility model.Here we briefly describe the wireless MobileIP implementation. We hope that Sun would provide the detailed version of thedocumentation in the future.The mobileIP scenario consists of Home-Agents(HA) and Foreign-Agents(FA) and have Mobile-Hosts(MH) moving betweentheir HA and FAs. The HA and FA are essentially base-station nodes we have described earlier. While MHs arebasically the mobileNodes described in section 16.1.1. The methods and procedures for MobileIP extensions are described in~ns/mip.{cc,h}, ~ns/mip-reg.cc, ~ns/tcl/lib/ns-mip.tcl and ~ns/tcl/lib/ns-wireless-mip.tcl.The HA and FA nodes are defined as MobileNode/MIPBS having a registering agent (regagent_) that sends beacon out to1 Refer to Chapter 32 for details on hierarchical routing and internals of HierNode.2 In order to do away with all these different variations of the definition of a node, we are planning to revise the node architecture that would allow a moreflexible and modularised construction of a node without the necessity of having to define and be limited to certain Class definitions only.162
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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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Page 133 and 134: Higher LayersNode 1Node 2. . .Node
Page 135 and 136: };void recv(Packet* p, Handler*);vi
Page 137 and 138: and the frame type. It then passes
Page 139 and 140: $ll_ set delay_ $delay$ll_ set band
Page 141 and 142: 14.10 Commands at a glanceThe follo
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Page 145 and 146: Chapter 16Mobile Networking in nsTh
Page 147 and 148: entry_addrdemuxIP addressdefaulttar
Page 149 and 150: 16.1.2 Creating Node movementsThe m
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Page 175 and 176: • Position/Sat/Geo A geostationar
Page 177 and 178: $ns add-isl $ltype $node1 $node2 $b
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Page 187 and 188: $satnode add-isl This method c
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Page 195 and 196: Chapter 20Directed DiffusionThe dir
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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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