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App2 3FilterF1FilterF24 5 6 71Directed Diffusion Core8Figure 20.1: Message flow in directed diffusionapps contains sample source and sink applications like gear, ping and rmst.lib has DiffusionRouting class definitions and definitions of diffusion application class. In addition there are sub-dirs calledmain and nr. main houses misc diffusion utility code. nr includes attribute definition and the class NR which is anabstract factory for the API (so that either ISI or MIT implementations may derive from it.ns contains ns wrappers for diffusion code.ăThese wrapper classes allow the core diffusion code and the diffusion API to beseamlessly incorporated into the NS class hierarchy. The DiffRoutingAgent is a wrapper for the Core Diffusion code,and DiffAppAgent is a wrapper for the DiffusionRouting (API) code.filter_core has the core diffusion agent.filters holds the different filters supported by diffusion implementation including two-phase-pull, one-phase-pull, gear, rmst,log, tag and srcrt (as of 10/03/03).The above Figure 20.1 is from SCADDS’ network routing API document available from their homepage (URL given earlier).The document describes attribute factories, matching rules for attributes, how applications interface with the core diffusionlayer, and filter/timer APIs. All messages coming from/going out in the network is received at/sent out from the core diffusionlayer. Messages can also come to core-diffusion layer from local applications and/or filters that might be connected to thenode. The applications use the publish/subscribe/send interface to send interest and data messages to the network.The core diffusion agent and diffusion application agent are attached to two well-known ports defined in ~ns//tcl/lib/nsdefault.tcl.Diffusion applications attached to the node call the underlying diffusion application agent for publishing/subscribing/sendingdata.20.3 Some mac issues for diffusion in nsIn the shim layer that sits between diffusion and ns, (see diffusion3/ns dir for code implementing this layer) all diffusionpackets are encapsulated within ns packets and are marked to be broadcasted. In previous versions all diffusion packets weremarked to be broadcast in ns. This is now changed. Now all diffusion pkts in ns uses the diffusion next_hop info thus allowingboth broadcast and unicast.So previously this only-brdcast feature supported for diffusion packets resulted in some problems at the mac layer. The mac-802.11 doesnot try to re-transmit a broadcast packet incase there is a collision and the packet is dropped. Coupled to this wasthe fact that mac-802.11 didn’t do random selection of slots in the contention window before it transmitted a packet (a brdcastdata or rts for unicast pkts). As a result there were a high number of collisions at the mac layer and a lot of packets were lost.This was fixed by adding random selection of slots before mac tx’ed a brdcast pkt (or a rts pkt).195
However if we have a large and dense topology, there is a chance that two or more nodes may select the same slot in themac contention window (the contention window size varies from 31 to 1023 for DSSS PHY MIB specifications). Thus nowwe need to add some extra jitter at the higher application layer. Diffusion has a provision to do this by compiling ns withthe macro USE_BROADCAST_MAC. What this does is it in addition to delaying certain messages (to avoid collisions),when run with a BROADCAST MAC layer, diffusion will use a different set of values for delays and jitters. These differentdelay/jitter values are defined under diffusion3/lib/main/config.hh. Since this might increase the latency you might want tofine-tune the delay values by hand.20.4 APIs for using filters in diffusionAs described earlier (see figure 20.1), filters can be attached to a diffusion node for various reasons. There can be basic diffusionfilters providing two-phase-pull (GradientFilter) and one-phase-pull (OnePhasePullFilter) diffusion routing algorithms.There is the GeoRoutingFilter or gear that provides a certain location (co-ordinate) based routing algorithm. There is alsoother filters for RMST routing algorithm (RmstFilter), logging (LogFilter), source routing (SourceRouteFilter) and tagging(TagFilter). See Commands at a glance section for details on APIs for adding filters to a diffusion node.20.5 Ping: an example diffusion application implementationThere is a ping application implemented under diffusion3/apps/ping subdir. The application consists of a ping sender andreceiver. The receiver requests for data by sending out “interest”s in the network. The interests get diffused through thenetwork. The ping-sender on receiving matching interests, sends out data.20.5.1 Ping Application as implemented in C++The ping-sender and -receiver classes, namely PingSenderApp and PingReceiverApp both derive from DiffApp, the parentclass for all diffusion based applications. See diffusion3/lib/diffapp{.cc,.hh} for detailed implementation of the DiffApp class.The ping-sender uses MySenderReceive object that handles all callbacks for it. Also the ping-sender defines two functionssetupSubscription() and setupPublication(). The first function creates interest attributes that matches with data attributes it(the sender) has to offer. Next it calls the dr-library function subscribe(). The subscription is used by the ping-sender to createan internal state against which attributes for interests received from the network are matched against. Incase of a match, thematching data is sent outinto the network. Function setupPublication() create attributes for the data it has to offer and callsthe library function publish() which inturn returns a publish handle. The ping-sender uses this handle to periodically send outdata which is forwarded by the gradient to core-diffusion to be sent out into the network only if it finds a matching interest.The ping-receiver object uses a similar callback object called MyReceiverReceive. And it defines a function setupSubscription()that creates attributes for the interest the receiver will be sending. Next it calls the dr library supported subscribe() whichsends the interest out into the network. The recv() function is used to recv matching data and the receiver then calculates thelatency for each data packet received from the ping-sender. The ping sender can be found under ping_sender.cc,.h. Andthe ping_receiver is implemented under ping_receiver.cc,.h. Some common defines and attribute factories for data/interestattributes are defined in ping.hh and ping_common.cc.196
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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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Page 147 and 148: entry_addrdemuxIP addressdefaulttar
Page 149 and 150: 16.1.2 Creating Node movementsThe m
Page 151 and 152: set netif $netif_($t)set mac $mac_(
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Page 161 and 162: Packet info at "Application level"
Page 163 and 164: The main problem facing the wired-c
Page 165 and 166: target_target_encapsulatorreg_agent
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Page 171 and 172: Chapter 17Satellite Networking in n
Page 173 and 174: in counter-rotating planes (where t
Page 175 and 176: • Position/Sat/Geo A geostationar
Page 177 and 178: $ns add-isl $ltype $node1 $node2 $b
Page 179 and 180: $satrouteobject_ compute_routeswher
Page 181 and 182: This will add an error model to the
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Page 185 and 186: from routing agentto Node->entrySat
Page 187 and 188: $satnode add-isl This method c
Page 189 and 190: set prop [new Propagation/FreeSpace
Page 191 and 192: 18.3.2 Using shadowing modelBefore
Page 193 and 194: Chapter 19Energy Model in nsEnergy
Page 195: Chapter 20Directed DiffusionThe dir
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Page 203 and 204: 21.2 Implementation of XCP in NSIn
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Page 207 and 208: Thruput2 0.054024 60000residue_pos_
Page 209 and 210: Chapter 22DelayBox: Per-Flow Delay
Page 211 and 212: $ns attach-agent $n_sink $sink# mak
Page 213 and 214: Chapter 23Changes made to the IEEE
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: }$sizeRNG next-substream# print the
Page 227 and 228: protected:RNG* rng_;};Classes deriv
Page 229 and 230: ns-random is implemented in ~ns/mis
Page 231 and 232: Chapter 26Trace and Monitoring Supp
Page 233 and 234: The monitor-queue function is const
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Page 239 and 240: PT_TORA,PT_DSR,PT_AODV,// insert ne
Page 241 and 242: The QueueMonitor class is not deriv
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Page 245 and 246: Chapter 27Test Suite SupportThe ns
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... ...}$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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