HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 41

Enabling multicast group replacement, Setting the 802.1p precedence for IGMP messages

Page 41 highlights

Enabling multicast group replacement For various reasons, the number of multicast groups that the switch or a port joins might exceed the upper limit. In addition, in some specific applications, a multicast group that the switch newly joins must replace an existing multicast group automatically. A typical example is channel switching. To view a new channel, a user switches from the current multicast group to the new one. To realize such requirements, you can enable the multicast group replacement function on the switch or on a certain port. When the number of multicast groups that the switch or on the port has joined reaches the limit, one of the following occurs: • If the multicast group replacement feature is disabled, new IGMP reports are automatically discarded. • If the multicast group replacement feature is enabled, the multicast group that the switch or a port newly joins automatically replaces an existing multicast group that has the lowest address. IMPORTANT: In the configuration, be sure to configure the maximum number of multicast groups allowed on a port (see "Setting the maximum number of multicast groups that a port can join") before enabling multicast group replacement. Otherwise, the multicast group replacement functionality will not take effect. Enabling multicast group replacement globally Step 1. Enter system view. 2. Enter IGMP-snooping view. 3. Enable multicast group replacement. Command system-view igmp-snooping overflow-replace [ vlan vlan-list ] Remarks N/A N/A Disabled by default Enabling multicast group replacement on a port Step 1. Enter system view. 2. Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view. 3. Enable multicast group replacement. Command system-view Remarks N/A interface interface-type interface-number Use either command. igmp-snooping overflow-replace [ vlan vlan-list ] Disabled by default. Setting the 802.1p precedence for IGMP messages You can change the 802.1p precedence for IGMP messages so that they can be assigned higher forwarding priority when congestion occurs on their outgoing ports. 30

  • 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

30
Enabling multicast group replacement
For various reasons, the number of multicast groups that the switch or a port joins might exceed the upper
limit. In addition, in some specific applications, a multicast group that the switch newly joins must replace
an existing multicast group automatically. A typical example is channel switching. To view a new channel,
a user switches from the current multicast group to the new one.
To realize such requirements, you can enable the multicast group replacement function on the switch or
on a certain port. When the number of multicast groups that the switch or on the port has joined reaches
the limit, one of the following occurs:
If the multicast group replacement feature is disabled, new IGMP reports are automatically
discarded.
If the multicast group replacement feature is enabled, the multicast group that the switch or a port
newly joins automatically replaces an existing multicast group that has the lowest address.
IMPORTANT:
In the configuration, be sure to configure the maximum number of multicast groups allowed on a port (see
"
Setting the maximum number of multicast groups that a port can join
") before enabling multicast group
replacement. Otherwise, the multicast group replacement functionality will not take effect.
Enabling multicast group replacement globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IGMP-snooping view.
igmp-snooping
N/A
3.
Enable multicast group
replacement.
overflow-replace
[
vlan
vlan-list
]
Disabled by default
Enabling multicast group replacement on a port
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface
interface-type
interface-number
Use either command.
3.
Enable multicast group
replacement.
igmp-snooping overflow-replace
[
vlan
vlan-list
]
Disabled by default.
Setting the 802.1p precedence for IGMP messages
You can change the 802.1p precedence for IGMP messages so that they can be assigned higher
forwarding priority when congestion occurs on their outgoing ports.