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Re: [ns] Strange Result
In wireless simulation, queue is not the only place where the packet
is dropped. Did you check if the packets are dropped in the mac ?
-Ya
On Mon, 29 Oct 2001, Harpreet Arora wrote:
> Hi,
> I've been using NS-2 to do wireless simulations. While I was trying to
> evaluate the effect of Queue length on the network performance, I came
> up on a very strange result. I simulated a small network with 5 nodes
> and 3 cbr sources, moving in an area of 500m X 500m, at a peak speed of
> 25 m/s. For a queue length of 20, I performed the simulations by varying
> the number of packets sent by each source during each simulation. The
> number of packets of each flow dropped was monitored. For one particular
> flow, the number of packet drops shows spikes at some points. If these
> points are ignored, the graph results in a smooth curve, which is very
> logical. The strange part is that, if the spiked points are plotted
> separately, it also results in a smooth curve. I have not been able to
> understand the phenomenon, even after prolonged investigation of the
> trace files. Could someone please explain me the reason for this? The
> results of the simulations are shown below. The spikes are shown by flow
> 2 and 3. Similar results occur with different scenario files and
> different Connection Patterns. Is it a bug in the ns-code, or are these
> just abberations which should be ignored?
>
> # of packets # of Packets # of Packets # of Packets Total #
> of Packets
> per source of flow 1 of flow 2 of flow
> 3 dropped (including
> dropped dropped
> dropped control packets)
> 50 1 0 0 2
> 53 1 0 0 2
> 54 0 0 0 2
> 57 1 0 0 2
> 58 1 6 0 8
> 61 1 0 0 2
> 62 1 0 0 2
> 64 1 0 0 2
> 66 1 1 0 4
> 69 1 0 0 4
> 70 1 2 0 4
> 73 1 0 0 2
> 74 1 1 0 3
> 76 1 0 0 2
> 78 1 1 0 3
> 80 1 0 0 3
> 83 1 0 0 2
> 85 1 9 0 11
> 87 1 0 0 4
> 88 1 9 0 11
> 90 1 1 0 3
> 93 2 0 0 2
> 94 1 0 0 2
> 97 1 0 0 2
> 99 1 1 0 3
> 100 2 0 0 2
> 103 1 0 0 2
> 105 2 0 0 3
> 107 1 0 1 3
> 108 1 0 2 4
> 111 1 0 0 2
> 112 1 0 0 2
> 115 1 0 0 2
> 117 1 12 0 14
> 118 1 12 0 14
> 120 1 0 0 2
> 123 1 0 0 2
> 124 1 0 0 2
> 127 0 0 0 2
> 128 1 0 5 7
> 131 1 0 0 2
> 132 1 14 0 16
> 135 1 0 0 3
> 137 1 0 0 2
> 138 1 0 0 2
> 140 1 14 0 16
> 142 1 0 0 2
> 145 1 0 0 2
> 146 1 0 9 11
> 148 1 0 0 2
> 151 1 0 10 12
> 153 1 0 0 3
> 155 1 0 0 2
> 156 1 0 0 2
> 158 1 1 0 5
> 160 1 1 0 3
> 162 1 0 12 14
> 165 1 0 0 2
> 166 1 0 13 15
> 169 1 0 0 2
> 170 1 1 0 3
> 172 1 0 0 2
> 175 1 0 15 17
> 176 1 0 0 2
> 178 0 1 0 2
> 180 1 1 0 4
> 183 1 0 0 2
> 185 1 0 0 2
> 187 1 0 17 19
> 189 2 0 0 4
> 190 1 0 0 3
> 192 1 20 0 22
> 194 1 0 19 21
> 197 1 0 0 2
> 199 1 0 0 2
> 200 1 0 0 3
> 202 1 0 0 2
> 205 1 22 0 24
> 207 1 0 0 2
> 208 1 1 22 25
> 211 1 0 0 3
> 213 1 1 0 3
> 214 1 0 24 26
> 217 1 0 0 3
> 218 1 0 0 2
> 220 1 0 0 2
> 223 1 0 0 2
> 225 1 23 0 25
> 226 1 0 0 2
> 229 1 0 0 2
> 231 1 0 0 2
> 233 1 1 26 29
> 235 1 0 0 2
> 237 1 0 0 2
> 239 1 0 28 30
> 241 1 0 0 2
> 242 1 24 0 26
> 245 1 0 0 2
> 247 1 0 29 31
> 248 1 29 0 31
> 250 1 0 0 2
> 252 1 0 0 2
> 255 1 31 0 33
> 257 1 0 31 33
> 259 1 1 0 3
> 260 1 0 33 35
> 262 1 32 0 34
> 264 1 0 0 2
> 266 1 0 0 2
> 269 1 0 0 2
> 271 1 28 0 30
> 272 1 0 0 2
> 274 1 0 36 38
> 277 1 0 0 2
> 279 1 35 0 37
> 281 1 0 0 3
> 282 1 0 0 4
> 285 2 0 0 3
> 287 1 1 0 3
> 289 1 0 0 2
> 290 1 1 0 4
> 292 1 0 0 3
> 295 1 0 0 2
> 296 1 1 0 3
> 299 1 0 0 2
> 300 1 1 0 3
> 302 2 0 0 3
> 304 1 0 41 43
> 306 1 0 0 2
> 308 1 1 0 3
> 311 1 0 0 2
> 313 1 0 0 2
> 314 1 0 0 2
> 316 1 2 0 4
> 318 1 2 2 7
> 320 1 2 2 6
> 322 1 3 2 8
> 324 1 3 4 9
> 327 2 3 47 55
> 329 1 3 5 10
> 331 1 47 6 56
> 333 1 5 6 13
> 334 1 5 8 17
> 336 1 6 9 17
> 338 1 6 10 20
> 340 2 5 10 18
> 342 1 6 11 19
> 344 1 7 12 23
> 346 1 6 12 22
> 349 1 7 14 23
> 351 1 8 14 26
> 353 1 8 58 68
> 354 1 8 59 69
> 357 2 9 17 30
> 358 2 11 17 32
> 360 1 10 18 32
> 362 1 11 18 32
> 364 1 11 62 75
> 367 2 10 20 33
> 368 2 43 22 68
> 371 2 11 22 36
> 372 2 11 23 37
> 374 1 14 24 40
> 376 2 13 68 84
> 379 1 14 26 42
> 380 2 14 26 43
> 383 2 14 27 45
> 385 3 14 28 46
> 386 2 46 28 77
> 388 1 15 30 49
> 391 2 15 31 49
> 393 1 15 30 47
> 394 1 17 32 51
> 396 1 16 75 93
> 399 1 17 33 52
> 400 1 18 34 54
> 403 2 18 78 99
> 405 1 20 36 60
> 406 1 19 37 58
> 409 1 19 37 58
> 411 2 21 38 62
> 413 1 20 39 61
> 414 3 52 40 96
> 417 2 20 83 106
> 419 1 22 42 67
> 420 2 65 42 110
> 423 1 22 43 68
> 424 2 22 44 70
> 426 1 23 45 70
> 429 1 25 46 75
> 431 2 25 47 77
> 432 1 26 47 75
> 435 1 25 49 78
> 436 1 25 48 75
> 439 3 57 50 111
> 441 1 25 50 78
> 443 1 26 94 122
> 444 2 27 52 84
> 446 1 29 53 85
> 449 1 27 53 84
> 451 3 27 98 129
> 453 2 30 55 90
> 455 1 29 99 130
> 457 1 29 57 89
> 459 1 29 101 132
> 460 1 32 58 92
> 463 2 30 59 92
> 464 2 30 104 137
> 467 1 31 61 94
> 468 1 32 61 96
> 470 1 31 62 95
> 473 1 32 63 97
> 475 2 32 107 142
> 477 3 33 65 102
> 478 1 34 66 102
> 480 3 33 66 103
> 483 3 79 67 150
> 484 1 35 68 105
> 486 3 37 69 111
> 489 1 36 70 109
> 490 3 80 70 154
> 493 3 38 114 156
> 494 1 38 72 112
> 497 3 69 73 146
> 498 3 37 117 158
>
>
> Thanks.
>
> Harpreet.
>
>