HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 71

Creating an RPF route,

Page 71 highlights

Figure 23 Changing an RPF route As shown in Figure 23, when no static multicast route is configured, Switch C's RPF neighbor on the path back to Source is Switch A. The multicast information from Source travels along the path from Switch A to Switch C, which is the unicast route between the two routers. When a static multicast route is configured on Switch C and Switch B is configured as Switch C's RPF neighbor on the path back to Source, the multicast information from Source travels from Switch A to Switch B and then to Switch C. Creating an RPF route When a unicast route is blocked, multicast traffic forwarding might be stopped because of lack of an RPF route. By configuring a static multicast route for a given multicast source, you can create an RPF route so that a multicast routing entry is created to guide multicast traffic forwarding regardless of whether a unicast route is available. Figure 24 Creating an RPF route Multicast Routing Table Static on Switch C Source/Mask Interface RPF neighbor/Mask 192.168.0.0/24 Vlan-int10 1.1.1.1/24 OSPF domain Switch D Receiver Multicast Routing Table Static on Switch D Source/Mask Interface RPF neighbor/Mask 192.168.0.0/24 Vlan-int20 2.2.2.2/24 Vlan-int20 2.2.2.1/24 Source 192.168.0.1/24 RIP domain Vlan-int10 Vlan-int10 1.1.1.1/24 1.1.1.2/24 Vlan-int20 2.2.2.2/24 Receiver Switch A Switch B Switch C Multicast packets Multicast static route As shown in Figure 24, the RIP domain and the OSPF domain are unicast isolated from each other. When no static multicast route is configured, the hosts (the receivers) in the OSPF domain cannot receive the multicast packets that the multicast source (the source) sent in the RIP domain. After you configure a static 60

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
  • 199
  • 200
  • 201
  • 202
  • 203
  • 204
  • 205
  • 206
  • 207
  • 208
  • 209
  • 210
  • 211
  • 212
  • 213
  • 214
  • 215
  • 216
  • 217
  • 218
  • 219
  • 220
  • 221
  • 222
  • 223
  • 224
  • 225
  • 226
  • 227
  • 228
  • 229
  • 230
  • 231
  • 232
  • 233
  • 234
  • 235
  • 236
  • 237
  • 238
  • 239
  • 240
  • 241
  • 242
  • 243
  • 244
  • 245
  • 246
  • 247
  • 248
  • 249
  • 250
  • 251
  • 252
  • 253
  • 254
  • 255
  • 256
  • 257
  • 258
  • 259
  • 260
  • 261
  • 262
  • 263
  • 264
  • 265
  • 266
  • 267
  • 268
  • 269
  • 270
  • 271
  • 272
  • 273
  • 274
  • 275
  • 276
  • 277
  • 278
  • 279
  • 280
  • 281
  • 282
  • 283
  • 284
  • 285
  • 286
  • 287
  • 288
  • 289
  • 290
  • 291
  • 292
  • 293
  • 294
  • 295
  • 296
  • 297
  • 298
  • 299
  • 300
  • 301
  • 302
  • 303
  • 304
  • 305
  • 306
  • 307
  • 308
  • 309
  • 310
  • 311
  • 312
  • 313
  • 314
  • 315
  • 316
  • 317
  • 318
  • 319
  • 320
  • 321
  • 322
  • 323
  • 324
  • 325
  • 326
  • 327
  • 328
  • 329
  • 330
  • 331
  • 332
  • 333
  • 334
  • 335
  • 336
  • 337
  • 338
  • 339
  • 340
  • 341
  • 342
  • 343
  • 344
  • 345
  • 346
  • 347
  • 348
  • 349
  • 350
  • 351
  • 352
  • 353
  • 354
  • 355
  • 356
  • 357
  • 358
  • 359
  • 360
  • 361
  • 362
  • 363
  • 364
  • 365
  • 366
  • 367
  • 368
  • 369
  • 370
  • 371
  • 372
  • 373
  • 374
  • 375
  • 376
  • 377
  • 378
  • 379

60
Figure 23
Changing an RPF route
As shown in
Figure 23
, when no static multicast route is configured, Switch C’s RPF neighbor on the path
back to Source is Switch A. The multicast information from Source travels along the path from Switch A
to Switch C, which is the unicast route between the two routers. When a static multicast route is
configured on Switch C and Switch B is configured as Switch C’s RPF neighbor on the path back to
Source, the multicast information from Source travels from Switch A to Switch B and then to Switch C.
Creating an RPF route
When a unicast route is blocked, multicast traffic forwarding might be stopped because of lack of an RPF
route. By configuring a static multicast route for a given multicast source, you can create an RPF route so
that a multicast routing entry is created to guide multicast traffic forwarding regardless of whether a
unicast route is available.
Figure 24
Creating an RPF route
As shown in
Figure 24
, the RIP domain and the OSPF domain are unicast isolated from each other. When
no static multicast route is configured, the hosts (the receivers) in the OSPF domain cannot receive the
multicast packets that the multicast source (the source) sent in the RIP domain. After you configure a static
Vlan-int10
1.1.1.2/24
Vlan-int10
1.1.1.1/24
Vlan-int20
2.2.2.2/24
Vlan-int20
2.2.2.1/24
Source
192.168.0.1/24
Source/Mask
Multicast Routing Table Static on Switch C
192.168.0.0/24
Interface
Vlan-int10
RPF neighbor/Mask
1.1.1.1/24
Source/Mask
Multicast Routing Table Static on Switch D
192.168.0.0/24
Interface
Vlan-int20
RPF neighbor/Mask
2.2.2.2/24
OSPF domain
RIP domain
Switch A
Switch B
Switch C
Switch D
Receiver
Receiver
Multicast packets
Multicast static route