The ns Manual (formerly ns Notes and Documentation)1 - NM Lab at ...

More documents

Recommendations

Info

Chapter 6Links: Simple LinksThis is the second aspect of defining the topology. In the previous chapter (Chapter 5), we had described how to create thenodes in the topology in ns. We now describe how to create the links to connect the nodes and complete the topology. In thischapter, we restrict ourselves to describing the simple point to point links. ns supports a variety of other media, including anemulation of a multi-access LAN using a mesh of simple links, and other true simulation of wireless and broadcast media.They will be described in a separate chapter. The CBQlink is derived from simple links and is a considerably more complexform of link that is also not described in this chapter.We begin by describing the commands to create a link in this section. As with the node being composed of classifiers, a simplelink is built up from a sequence of connectors. We also briefly describe some of the connectors in a simple link. We thendescribe the instance procedures that operate on the various components of defined by some of these connectors (Section 6.1).We conclude the chapter with a description the connector object (Section 6.2), including brief descriptions of the commonlink connectors.The class Link is a standalone class in OTcl, that provides a few simple primitives. The class SimpleLink providesthe ability to connect two nodes with a point to point link. ns provides the instance procedure simplex-link{} to form aunidirectional link from one node to another. The link is in the class SimpleLink. The following describes the syntax of thesimplex link:set ns [new Simulator]$ns simplex-link 〈node0〉〈node1〉〈bandwidth〉〈delay〉〈queue_type〉The command creates a link from 〈node0〉 to 〈node1〉, with specified 〈bandwidth〉 and 〈delay〉 characteristics. Thelink uses a queue of type 〈queue_type〉. The procedure also adds a TTL checker to the link. Five instance variables definethe link:head_ Entry point to the link, it points to the first object in the link.queue_ Reference to the main queue element of the link. Simple links usuallyhave one queue per link. Other more complex types of links may havemultiple queue elements in the link.link_ A reference to the element that actually models the link, in terms of thedelay and bandwidth characteristics of the link.ttl_ Reference to the element that manipulates the ttl in every packet.drophead_ Reference to an object that is the head of a queue of elements that processlink drops.In addition, if the simulator instance variable, $traceAllFile_, is defined, the procedure will add trace elements that63
Linkhead_enqT_queue_ deqT_ link_ ttl_rcvT_drophead_drpT_Figure 6.1: Composite Construction of a Unidirectional Linktrack when a packet is enqueued and dequeued from queue_. Furthermore, tracing interposes a drop trace element after thedrophead_. The following instance variables track the trace elements:enqT_ Reference to the element that traces packets entering queue_.deqT_ Reference to the element that traces packets leaving queue_.drpT_ Reference to the element that traces packets dropped from queue_.rcvT_ Reference to the element that traces packets received by the next node.Note however, that if the user enable tracing multiple times on the link, these instance variables will only store a reference tothe last elements inserted.Other configuration mechanisms that add components to a simple link are network interfaces (used in multicast routing),link dynamics models, and tracing and monitors. We give a brief overview of the related objects at the end of this chapter(Section 6.2), and discuss their functionality/implementation in other chapters.The instance procedure duplex-link{} constructs a bi-directional link from two simplex links.6.1 Instance Procedures for Links and SimpleLinksLink procedures The class Link is implemented entirely in Otcl. The OTcl SimpleLink class uses the C++LinkDelay class to simulate packet delivery delays. The instance procedures in the class Link are:64
Page 6 and 7:
18 Radio Propagation Models 17718.1
Page 8 and 9:
30 Multicast Routing 25130.1 Multic
Page 10 and 11:
38.2.5 An example . . . . . . . . .
Page 12 and 13:
X Other 40347 Educational use of NS
Page 14: # so, we lied. now, we define the t
Page 17 and 18: Chapter 2Undocumented FacilitiesNs
Page 19 and 20: Part IInterface to the Interpreter1
Page 21 and 22: • if you can do what you want by
Page 23 and 24: • tcl.result(const char* s)Pass t
Page 25 and 26: By convention in ns, the class Agen
Page 27 and 28: $object set bwvar 1500kb$object set
Page 29 and 30: For a C++ variable to be traceable,
Page 31 and 32: 3.5 Class TclClassThis compiled cla
Page 33 and 34: class Packet {......static int hdrl
Page 35 and 36: The actual arguments passed by the
Page 37 and 38: class TclClass (Section 3.5) define
Page 39 and 40: Chapter 4The Class SimulatorThe ove
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
Page 55 and 56: };The class imposes no direct seman
Page 57 and 58: flow-specific queuing disciplines a
Page 59 and 60: 5.5 Routing Module and Classifier O
Page 61 and 62: Module NameRtModule/BaseRtModule/Mc
Page 63: $node neighborsThis returns the lis
Page 67 and 68: 6.2 ConnectorsConnectors, unlink cl
Page 69 and 70: $ns_ link-lossmodel This function
Page 71 and 72: Chapter 7Queue Management and Packe
Page 73 and 74: }}}void Queue::resume(){Packet* p =
Page 75 and 76: 7.3 Different types of Queue object
Page 77 and 78: maxidle_ is the maximum amount of t
Page 79 and 80: dst_ The destination address of pac
Page 81 and 82: 7.5.2 ConfigurationRunning a JoBS s
Page 83 and 84: mean_pkt_size_ Used to set the expe
Page 85 and 86: Demarker objects$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) :
Page 107 and 108: 10.6.4 Using the agent through OTcl
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
Page 131 and 132:
This is a simple example of how to
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
Page 143 and 144:
15.2.1 Default Hierarchical Setting
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
Page 151 and 152:
set netif $netif_($t)set mac $mac_(
Page 153 and 154:
the hardware address of a packet’
Page 155 and 156:
destined to itself to the port dmux
Page 157 and 158:
switch(ch->ptype()) {case PT_MAC:br
Page 159 and 160:
16.1.7 Revised format for wireless
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
Page 167 and 168:
why: This avoids header clashes bet
Page 169 and 170:
This command is used to create a Go
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
Page 183 and 184:
lh_firstnameobj‘‘name’’ is
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 and 196:
Chapter 20Directed DiffusionThe dir
Page 197 and 198:
However if we have a large and dens
Page 199 and 200:
yr application in the ns context. T
Page 201 and 202:
value of opt(pre-stop) is usually t
Page 203 and 204:
21.2 Implementation of XCP in NSIn
Page 205 and 206:
the persistent queue length in the
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
Page 235 and 236:
also used to accumulate packet drop
Page 237 and 238:
}name,th->size(),flags,iph->flowid(
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:
$ns_ trace-all This is the command
Page 245 and 246:
Chapter 27Test Suite SupportThe ns
Page 247 and 248:
... ...}$ns_ at $opt(stop).1 "$self
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
Page 261 and 262:
This dumps next hop information in
Page 263 and 264:
$ns mrtproto ST;# specify shared tr
Page 265 and 266:
Dense Mode The Dense Mode protocol
Page 267 and 268:
and unique label (id). Thus, “inc
Page 269 and 270:
add-iif{ifid link},add-oif{link if}
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
Page 277 and 278:
v 0.8123 link-up 3 5v 0.8123 link-u
Page 279 and 280:
The first argument is the time at w
Page 281 and 282:
$ns_ rtmodel This command defines
Page 283 and 284:
$ns set-address-format hierarchical
Page 285 and 286:
32.4 Hierarchical Routing with Sess
Page 287 and 288:
Chapter 33UDP Agents33.1 UDP Agents
Page 289 and 290:
Chapter 34TCP AgentsThis section de
Page 291 and 292:
set ns [new Simulator]set node1 [$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
Page 299 and 300:
Chapter 35SCTP AgentsThis chapter d
Page 301 and 302:
Figure 35.1: Example of a Multihome
Page 303 and 304:
Note: the actual value of these tra
Page 305 and 306:
1.526624 1 4 sctp 1500 -------D 0 1
Page 307 and 308:
$ns at 5.0 "finish"$ns run35.5.2 Mu
Page 309 and 310:
Chapter 36Agent/SRMThis chapter des
Page 311 and 312:
36.1.2 Other Configuration Paramete
Page 313 and 314:
3.6274 n 0 m r 1 type repair servi
Page 315 and 316:
3.6029 n 3 m r 2 Q NTIMER at 3.730
Page 317 and 318:
36.4 Loss Detection—The Class SRM
Page 319 and 320:
same packet. The repair objet does
Page 321 and 322:
}hdr_asrm* seh = (hdr_asrm*) p->acc
Page 323 and 324:
set grp [Node allocaddr]$srm set ds
Page 325 and 326:
#set up the multicast routingDM set
Page 327 and 328:
37.3 Architecture of the PLM Protoc
Page 329 and 330:
We add in void PLMLossMonitor::recv
Page 331 and 332:
Part VIApplication330
Page 333 and 334:
Traffic generatorsApplication/Traff
Page 335 and 336:
• recv(int nbytes)—Announces th
Page 337 and 338:
1. EXPOO_Traffic—generates traffi
Page 339 and 340:
set src [new Agent/UDP]set sink [ne
Page 341 and 342:
Application FTP FTP objects produce
Page 343 and 344:
send_data(ADU)Application(HttpApp,
Page 345 and 346:
39.1.4 Transmitting user data over
Page 347 and 348:
and teardown of connections. Only O
Page 349 and 350:
TclObjectPagePoolPagePool/CompMathP
Page 351 and 352:
PagePool/ProxyTrace takes these two
Page 353 and 354:
}int id_; // object IDWebTrafSessio
Page 355 and 356:
An Http/Server object waits for inc
Page 357 and 358:
set tmp [new RandomVariable/Exponen
Page 359 and 360:
Object Type Event Type Explaination
Page 361 and 362:
Chapter 40Worm ModelIn this chapter
Page 363 and 364:
$w local-p 0.5Following are some co
Page 365 and 366:
(nsnode) clientcloudPackM ime(nsnod
Page 367 and 368:
HTTP responsesclients servers Delay
Page 369 and 370:
41.5 Commands at a GlanceThe follow
Page 371 and 372:
• HTTP response size (bytes)• s
Page 373 and 374:
Chapter 42Session-level Packet Dist
Page 375 and 376:
42.1.2 Inserting a Loss ModuleWhen
Page 377 and 378:
Delay and Loss Modules Each receive
Page 379 and 380:
Chapter 43Asim: approximate analyti
Page 381 and 382:
set n(1) [$ns node]set link(0:1) [$
Page 383 and 384:
Part VIIIEmulation382
Page 385 and 386:
When using the emulation mode, a sp
Page 387 and 388:
set intf [$pf1 open readonly]puts "
Page 389 and 390:
puts "install nets into taps..."$a0
Page 391 and 392:
Chapter 45Nam45.1 IntroductionNam i
Page 393 and 394:
• Button 6 (Chevron logo) - Close
Page 395 and 396:
Second, when dealing with randomly
Page 397 and 398:
dst_portaddr,seqno,flags,sname);A n
Page 399 and 400:
• up• down• right• left•
Page 401 and 402:
46.1.7 Agent TracingAgent trace eve
Page 403 and 404:
v -t 1.0 -e node_tclscript 2 "Echo
Page 405 and 406:
If nam ever gets to the end of an e
Page 407 and 408:
l :link-t time-s source id-d des
Page 409 and 410:
E :D :P :a :session enqueue-t time
Page 411 and 412:
v :V :N :W :g :A :c :q :execute tcl
Page 413 and 414:
$ns duplex-link-op orient right$ns
Page 415 and 416:
Chapter 47Educational use of NS and
Page 417 and 418:
Bibliography[1] C. Alaettinoğlu, A
show all

The ns Manual (formerly ns Notes and Documentation)1 - NM Lab at ...

Create successful ePaper yourself

Delete template?

Save as template?