doc/user/pim.rst

   1 .. _pim:
   2
   3 ***
   4 PIM
   5 ***
   6
   7 PIM -- Protocol Independent Multicast
   8
   9 *pimd* supports pim-sm as well as igmp v2 and v3. pim is
  10 vrf aware and can work within the context of vrf's in order to
  11 do S,G mrouting.  Additionally PIM can be used in the EVPN underlay
  12 network for optimizing forwarding of overlay BUM traffic.
  13
  14 .. note::
  15
  16    On Linux for PIM-SM operation you *must* have kernel version 4.18 or greater.
  17    To use PIM for EVPN BUM forwarding, kernels 5.0 or greater are required.
  18    OpenBSD has no multicast support and FreeBSD, NetBSD and Solaris only
  19    have support for SSM.
  20
  21 .. _starting-and-stopping-pimd:
  22
  23 Starting and Stopping pimd
  24 ==========================
  25
  26 The default configuration file name of *pimd*'s is :file:`pimd.conf`. When
  27 invoked *pimd* searches directory |INSTALL_PREFIX_ETC|. If
  28 :file:`pimd.conf` is not there then next search current directory.
  29
  30 *pimd* requires zebra for proper operation. Additionally *pimd* depends on
  31 routing properly setup and working in the network that it is working on.
  32
  33 ::
  34
  35    # zebra -d
  36    # pimd -d
  37
  38
  39 Please note that *zebra* must be invoked before *pimd*.
  40
  41 To stop *pimd* please use::
  42
  43    kill `cat /var/run/pimd.pid`
  44
  45 Certain signals have special meanings to *pimd*.
  46
  47 +---------+---------------------------------------------------------------------+
  48 | Signal  | Meaning                                                             |
  49 +=========+=====================================================================+
  50 | SIGUSR1 | Rotate the *pimd* logfile                                           |
  51 +---------+---------------------------------------------------------------------+
  52 | SIGINT  | *pimd* sweeps all installed PIM mroutes then terminates gracefully. |
  53 | SIGTERM |                                                                     |
  54 +---------+---------------------------------------------------------------------+
  55
  56 *pimd* invocation options. Common options that can be specified
  57 (:ref:`common-invocation-options`).
  58
  59 .. index:: ip pim rp A.B.C.D A.B.C.D/M
  60 .. clicmd:: ip pim rp A.B.C.D A.B.C.D/M
  61
  62    In order to use pim, it is necessary to configure a RP for join messages to
  63    be sent to. Currently the only methodology to do this is via static rp
  64    commands. All routers in the pim network must agree on these values. The
  65    first ip address is the RP's address and the second value is the matching
  66    prefix of group ranges covered. This command is vrf aware, to configure for
  67    a vrf, enter the vrf submode.
  68
  69 .. index:: ip pim register-accept-list PLIST
  70 .. clicmd:: ip pim register-accept-list PLIST
  71
  72    When pim receives a register packet the source of the packet will be compared
  73    to the prefix-list specified, PLIST, and if a permit is received normal
  74    processing continues.  If a deny is returned for the source address of the
  75    register packet a register stop message is sent to the source.
  76
  77 .. index:: ip pim spt-switchover infinity-and-beyond
  78 .. clicmd:: ip pim spt-switchover infinity-and-beyond
  79
  80    On the last hop router if it is desired to not switch over to the SPT tree.
  81    Configure this command. This command is vrf aware, to configure for a vrf,
  82    enter the vrf submode.
  83
  84 .. index:: ip pim ecmp
  85 .. clicmd:: ip pim ecmp
  86
  87    If pim has the a choice of ECMP nexthops for a particular RPF, pim will
  88    cause S,G flows to be spread out amongst the nexthops. If this command is
  89    not specified then the first nexthop found will be used. This command is vrf
  90    aware, to configure for a vrf, enter the vrf submode.
  91
  92 .. index:: ip pim ecmp rebalance
  93 .. clicmd:: ip pim ecmp rebalance
  94
  95    If pim is using ECMP and an interface goes down, cause pim to rebalance all
  96    S,G flows across the remaining nexthops. If this command is not configured
  97    pim only modifies those S,G flows that were using the interface that went
  98    down. This command is vrf aware, to configure for a vrf, enter the vrf
  99    submode.
 100
 101 .. index:: ip pim join-prune-interval (60-600)
 102 .. clicmd:: ip pim join-prune-interval (60-600)
 103
 104    Modify the join/prune interval that pim uses to the new value. Time is
 105    specified in seconds. This command is vrf aware, to configure for a vrf,
 106    enter the vrf submode.
 107
 108 .. index:: ip pim keep-alive-timer (31-60000)
 109 .. clicmd:: ip pim keep-alive-timer (31-60000)
 110
 111    Modify the time out value for a S,G flow from 31-60000 seconds. 31 seconds
 112    is chosen for a lower bound because some hardware platforms cannot see data
 113    flowing in better than 30 second chunks. This command is vrf aware, to
 114    configure for a vrf, enter the vrf submode.
 115
 116 .. index:: ip pim packets (1-100)
 117 .. clicmd:: ip pim packets (1-100)
 118
 119    When processing packets from a neighbor process the number of packets
 120    incoming at one time before moving on to the next task. The default value is
 121    3 packets.  This command is only useful at scale when you can possibly have
 122    a large number of pim control packets flowing. This command is vrf aware, to
 123    configure for a vrf, enter the vrf submode.
 124
 125 .. index:: ip pim register-suppress-time (5-60000)
 126 .. clicmd:: ip pim register-suppress-time (5-60000)
 127
 128    Modify the time that pim will register suppress a FHR will send register
 129    notifications to the kernel. This command is vrf aware, to configure for a
 130    vrf, enter the vrf submode.
 131
 132 .. index:: ip pim send-v6-secondary
 133 .. clicmd:: ip pim send-v6-secondary
 134
 135    When sending pim hello packets tell pim to send any v6 secondary addresses
 136    on the interface. This information is used to allow pim to use v6 nexthops
 137    in it's decision for RPF lookup. This command is vrf aware, to configure for
 138    a vrf, enter the vrf submode.
 139
 140 .. index:: ip pim ssm prefix-list WORD
 141 .. clicmd:: ip pim ssm prefix-list WORD
 142
 143    Specify a range of group addresses via a prefix-list that forces pim to
 144    never do SM over. This command is vrf aware, to configure for a vrf, enter
 145    the vrf submode.
 146
 147 .. index:: ip multicast rpf-lookup-mode WORD
 148 .. clicmd:: ip multicast rpf-lookup-mode WORD
 149
 150    Modify how PIM does RPF lookups in the zebra routing table.  You can use
 151    these choices:
 152
 153    longer-prefix
 154       Lookup the RPF in both tables using the longer prefix as a match
 155
 156    lower-distance
 157       Lookup the RPF in both tables using the lower distance as a match
 158
 159    mrib-only
 160       Lookup in the Multicast RIB only
 161
 162    mrib-then-urib
 163       Lookup in the Multicast RIB then the Unicast Rib, returning first found.
 164       This is the default value for lookup if this command is not entered
 165
 166    urib-only
 167       Lookup in the Unicast Rib only.
 168
 169 .. index:: no ip msdp mesh-group [WORD]
 170 .. clicmd:: no ip msdp mesh-group [WORD]
 171
 172    Delete multicast source discovery protocol mesh-group
 173
 174 .. index:: ip igmp generate-query-once [version (2-3)]
 175 .. clicmd:: ip igmp generate-query-once [version (2-3)]
 176
 177    Generate IGMP query (v2/v3) on user requirement. This will not depend on
 178    the existing IGMP general query timer.If no version is provided in the cli,
 179    it will be considered as default v2 query.This is a hidden command.
 180
 181 .. index:: [no] ip igmp watermark-warn (10-60000)
 182 .. clicmd:: [no] ip igmp watermark-warn (10-60000)
 183
 184    Configure watermark warning generation for an igmp group limit. Generates
 185    warning once the configured group limit is reached while adding new groups.
 186    'no' form of the command disables the warning generation. This command is
 187    vrf aware. To configure per vrf, enter vrf submode.
 188
 189 .. _pim-interface-configuration:
 190
 191 PIM Interface Configuration
 192 ===========================
 193
 194 PIM interface commands allow you to configure an interface as either a Receiver
 195 or a interface that you would like to form pim neighbors on. If the interface
 196 is in a vrf, enter the interface command with the vrf keyword at the end.
 197
 198 .. index:: ip pim active-active
 199 .. clicmd:: ip pim active-active
 200
 201    Turn on pim active-active configuration for a Vxlan interface.  This
 202    command will not do anything if you do not have the underlying ability
 203    of a mlag implementation.
 204
 205 .. index:: ip pim bfd
 206 .. clicmd:: ip pim bfd
 207
 208    Turns on BFD support for PIM for this interface.
 209
 210 .. index:: ip pim bsm
 211 .. clicmd:: ip pim bsm
 212
 213    Tell pim that we would like to use this interface to process bootstrap
 214    messages. This is enabled by default. 'no' form of this command is used to
 215    restrict bsm messages on this interface.
 216
 217 .. index:: ip pim unicast-bsm
 218 .. clicmd:: ip pim unicast-bsm
 219
 220    Tell pim that we would like to allow interface to process unicast bootstrap
 221    messages. This is enabled by default. 'no' form of this command is used to
 222    restrict processing of unicast bsm messages on this interface.
 223
 224 .. index:: ip pim drpriority (1-4294967295)
 225 .. clicmd:: ip pim drpriority (1-4294967295)
 226
 227    Set the DR Priority for the interface. This command is useful to allow the
 228    user to influence what node becomes the DR for a lan segment.
 229
 230 .. index:: ip pim hello (1-180) (1-180)
 231 .. clicmd:: ip pim hello (1-180) (1-180)
 232
 233    Set the pim hello and hold interval for a interface.
 234
 235 .. index:: ip pim
 236 .. clicmd:: ip pim
 237
 238    Tell pim that we would like to use this interface to form pim neighbors
 239    over. Please note that this command does not enable the reception of IGMP
 240    reports on the interface. Refer to the next `ip igmp` command for IGMP
 241    management.
 242
 243 .. index:: ip igmp
 244 .. clicmd:: ip igmp
 245
 246    Tell pim to receive IGMP reports and Query on this interface. The default
 247    version is v3. This command is useful on a LHR.
 248
 249 .. index:: ip igmp join A.B.C.D [A.B.C.D]
 250 .. clicmd:: ip igmp join A.B.C.D [A.B.C.D]
 251
 252    Join multicast group or source-group on an interface.
 253
 254 .. index:: ip igmp query-interval (1-1800)
 255 .. clicmd:: ip igmp query-interval (1-1800)
 256
 257    Set the IGMP query interval that PIM will use.
 258
 259 .. index:: ip igmp query-max-response-time (10-250)
 260 .. clicmd:: ip igmp query-max-response-time (10-250)
 261
 262    Set the IGMP query response timeout value. If an report is not returned in
 263    the specified time we will assume the S,G or \*,G has timed out.
 264
 265 .. index:: ip igmp version (2-3)
 266 .. clicmd:: ip igmp version (2-3)
 267
 268    Set the IGMP version used on this interface. The default value is 3.
 269
 270 .. index:: ip multicast boundary oil WORD
 271 .. clicmd:: ip multicast boundary oil WORD
 272
 273    Set a pim multicast boundary, based upon the WORD prefix-list. If a pim join
 274    or IGMP report is received on this interface and the Group is denied by the
 275    prefix-list, PIM will ignore the join or report.
 276
 277 .. index:: ip igmp last-member-query-count (1-7)
 278 .. clicmd:: ip igmp last-member-query-count (1-7)
 279
 280    Set the IGMP last member query count. The default value is 2. 'no' form of
 281    this command is used to to configure back to the default value.
 282
 283 .. index:: ip igmp last-member-query-interval (1-255)
 284 .. clicmd:: ip igmp last-member-query-interval (1-255)
 285
 286    Set the IGMP last member query interval in deciseconds. The default value is
 287    10 deciseconds. 'no' form of this command is used to to configure back to the
 288    default value.
 289
 290 .. index:: ip mroute INTERFACE A.B.C.D [A.B.C.D]
 291 .. clicmd:: ip mroute INTERFACE A.B.C.D [A.B.C.D]
 292
 293    Set a static multicast route for a traffic coming on the current interface to
 294    be forwarded on the given interface if the traffic matches the group address
 295    and optionally the source address.
 296
 297 .. _pim-multicast-rib-insertion:
 298
 299 PIM Multicast RIB insertion:
 300 ============================
 301
 302 In order to influence Multicast RPF lookup, it is possible to insert
 303 into zebra routes for the Multicast RIB. These routes are only
 304 used for RPF lookup and will not be used by zebra for insertion
 305 into the kernel *or* for normal rib processing. As such it is
 306 possible to create weird states with these commands. Use with
 307 caution. Most of the time this will not be necessary.
 308
 309 .. index:: ip mroute A.B.C.D/M A.B.C.D (1-255)
 310 .. clicmd:: ip mroute A.B.C.D/M A.B.C.D (1-255)
 311
 312    Insert into the Multicast Rib Route A.B.C.D/M with specified nexthop. The
 313    distance can be specified as well if desired.
 314
 315 .. index:: ip mroute A.B.C.D/M INTERFACE (1-255)
 316 .. clicmd:: ip mroute A.B.C.D/M INTERFACE (1-255)
 317
 318    Insert into the Multicast Rib Route A.B.C.D/M using the specified INTERFACE.
 319    The distance can be specified as well if desired.
 320
 321 .. _show-pim-information:
 322
 323 Show PIM Information
 324 ====================
 325
 326 All PIM show commands are vrf aware and typically allow you to insert a
 327 specified vrf command if information is desired about a specific vrf. If no
 328 vrf is specified then the default vrf is assumed. Finally the special keyword
 329 'all' allows you to look at all vrfs for the command. Naming a vrf 'all' will
 330 cause great confusion.
 331
 332 .. index:: show ip igmp interface
 333 .. clicmd:: show ip igmp interface
 334
 335    Display IGMP interface information.
 336
 337 .. index:: show ip igmp join
 338 .. clicmd:: show ip igmp join
 339
 340    Display IGMP static join information.
 341
 342 .. index:: show ip igmp groups
 343 .. clicmd:: show ip igmp groups
 344
 345    Display IGMP groups information.
 346
 347 .. index:: show ip igmp groups retransmissions
 348 .. clicmd:: show ip igmp groups retransmissions
 349
 350    Display IGMP group retransmission information.
 351
 352 .. index:: show ip igmp sources
 353 .. clicmd:: show ip igmp sources
 354
 355    Display IGMP sources information.
 356
 357 .. index:: show ip igmp sources retransmissions
 358 .. clicmd:: show ip igmp sources retransmissions
 359
 360    Display IGMP source retransmission information.
 361
 362 .. index:: show ip igmp statistics
 363 .. clicmd:: show ip igmp statistics
 364
 365    Display IGMP statistics information.
 366
 367 .. index:: show ip multicast
 368 .. clicmd:: show ip multicast
 369
 370    Display various information about the interfaces used in this pim instance.
 371
 372 .. index:: show ip mroute [vrf NAME] [A.B.C.D [A.B.C.D]] [fill] [json]
 373 .. clicmd:: show ip mroute [vrf NAME] [A.B.C.D [A.B.C.D]] [fill] [json]
 374
 375    Display information about installed into the kernel S,G mroutes.  If
 376    one address is specified we assume it is the Group we are interested
 377    in displaying data on.  If the second address is specified then it is
 378    Source Group.  The keyword `fill` says to fill in all assumed data
 379    for test/data gathering purposes.
 380
 381 .. index:: show ip mroute count
 382 .. clicmd:: show ip mroute count
 383
 384    Display information about installed into the kernel S,G mroutes and in
 385    addition display data about packet flow for the mroutes.
 386
 387 .. index:: show ip mroute summary
 388 .. clicmd:: show ip mroute summary
 389
 390    Display total number of S,G mroutes and number of S,G mroutes installed
 391    into the kernel.
 392
 393 .. index:: show ip pim assert
 394 .. clicmd:: show ip pim assert
 395
 396    Display information about asserts in the PIM system for S,G mroutes.
 397
 398 .. index:: show ip pim assert-internal
 399 .. clicmd:: show ip pim assert-internal
 400
 401    Display internal assert state for S,G mroutes
 402
 403 .. index:: show ip pim assert-metric
 404 .. clicmd:: show ip pim assert-metric
 405
 406    Display metric information about assert state for S,G mroutes
 407
 408 .. index:: show ip pim assert-winner-metric
 409 .. clicmd:: show ip pim assert-winner-metric
 410
 411    Display winner metric for assert state for S,G mroutes
 412
 413 .. index:: show ip pim group-type
 414 .. clicmd:: show ip pim group-type
 415
 416    Display SSM group ranges.
 417
 418 .. index:: show ip pim interface
 419 .. clicmd:: show ip pim interface
 420
 421    Display information about interfaces PIM is using.
 422
 423 .. index:: show ip pim mlag [vrf NAME] interface [detail|WORD] [json]
 424 .. clicmd:: show ip pim mlag [vrf NAME|all] interface [detail|WORD] [json]
 425
 426    Display mlag interface information.
 427
 428 .. index:: show ip pim [vrf NAME] join [A.B.C.D [A.B.C.D]] [json]
 429 .. clicmd:: show ip pim join
 430
 431    Display information about PIM joins received.  If one address is specified
 432    then we assume it is the Group we are interested in displaying data on.
 433    If the second address is specified then it is Source Group.
 434
 435 .. index:: show ip pim local-membership
 436 .. clicmd:: show ip pim local-membership
 437
 438    Display information about PIM interface local-membership.
 439
 440 .. index:: show ip pim mlag summary [json]
 441 .. clicmd:: show ip pim mlag summary [json]
 442
 443    Display mlag information state that PIM is keeping track of.
 444
 445 .. index:: show ip pim neighbor
 446 .. clicmd:: show ip pim neighbor
 447
 448    Display information about PIM neighbors.
 449
 450 .. index:: show ip pim nexthop
 451 .. clicmd:: show ip pim nexthop
 452
 453    Display information about pim nexthops that are being used.
 454
 455 .. index:: show ip pim nexthop-lookup
 456 .. clicmd:: show ip pim nexthop-lookup
 457
 458    Display information about a S,G pair and how the RPF would be chosen. This
 459    is especially useful if there are ECMP's available from the RPF lookup.
 460
 461 .. index:: show ip pim rp-info
 462 .. clicmd:: show ip pim rp-info
 463
 464    Display information about RP's that are configured on this router.
 465
 466 .. index:: show ip pim rpf
 467 .. clicmd:: show ip pim rpf
 468
 469    Display information about currently being used S,G's and their RPF lookup
 470    information. Additionally display some statistics about what has been
 471    happening on the router.
 472
 473 .. index:: show ip pim secondary
 474 .. clicmd:: show ip pim secondary
 475
 476    Display information about an interface and all the secondary addresses
 477    associated with it.
 478
 479 .. index:: show ip pim state
 480 .. clicmd:: show ip pim state
 481
 482    Display information about known S,G's and incoming interface as well as the
 483    OIL and how they were chosen.
 484
 485 .. index:: show ip pim [vrf NAME] upstream [A.B.C.D [A.B.C.D]] [json]
 486 .. clicmd:: show ip pim upstream
 487
 488    Display upstream information about a S,G mroute.  Allow the user to
 489    specify sub Source and Groups that we are only interested in.
 490
 491 .. index:: show ip pim upstream-join-desired
 492 .. clicmd:: show ip pim upstream-join-desired
 493
 494    Display upstream information for S,G's and if we desire to
 495    join the multicast tree
 496
 497 .. index:: show ip pim upstream-rpf
 498 .. clicmd:: show ip pim upstream-rpf
 499
 500    Display upstream information for S,G's and the RPF data associated with them.
 501
 502 .. index:: show ip pim [vrf NAME] mlag upstream [A.B.C.D [A.B.C.D]] [json]
 503 .. clicmd:: show ip pim mlag upstream
 504
 505    Display upstream entries that are synced across MLAG switches.
 506    Allow the user to specify sub Source and Groups address filters.
 507
 508 .. index:: show ip pim mlag summary
 509 .. clicmd:: show ip pim mlag summary
 510
 511    Display PIM MLAG (multi-chassis link aggregation) session status and
 512    control message statistics.
 513
 514 .. index:: show ip pim bsr
 515 .. clicmd:: show ip pim bsr
 516
 517    Display current bsr, its uptime and last received bsm age.
 518
 519 .. index:: show ip pim bsrp-info
 520 .. clicmd:: show ip pim bsrp-info
 521
 522    Display group-to-rp mappings received from E-BSR.
 523
 524 .. index:: show ip pim bsm-database
 525 .. clicmd:: show ip pim bsm-database
 526
 527    Display all fragments ofstored bootstrap message in user readable format.
 528
 529 .. index:: show ip rpf
 530 .. clicmd:: show ip rpf
 531
 532    Display the multicast RIB created in zebra.
 533
 534 .. index:: mtrace A.B.C.D [A.B.C.D]
 535 .. clicmd:: mtrace A.B.C.D [A.B.C.D]
 536
 537    Display multicast traceroute towards source, optionally for particular group.
 538
 539 .. index:: show ip multicast count [vrf NAME] [json]
 540 .. clicmd:: show ip multicast count [vrf NAME] [json]
 541
 542    Display multicast data packets count per interface for a vrf.
 543
 544 .. index:: show ip multicast count vrf all [json]
 545 .. clicmd:: show ip multicast count vrf all [json]
 546
 547    Display multicast data packets count per interface for all vrf.
 548
 549 PIM Debug Commands
 550 ==================
 551
 552 The debugging subsystem for PIM behaves in accordance with how FRR handles
 553 debugging. You can specify debugging at the enable CLI mode as well as the
 554 configure CLI mode. If you specify debug commands in the configuration cli
 555 mode, the debug commands can be persistent across restarts of the FRR pimd if
 556 the config was written out.
 557
 558 .. index:: debug igmp
 559 .. clicmd:: debug igmp
 560
 561    This turns on debugging for IGMP protocol activity.
 562
 563 .. index:: debug mtrace
 564 .. clicmd:: debug mtrace
 565
 566    This turns on debugging for mtrace protocol activity.
 567
 568 .. index:: debug mroute
 569 .. clicmd:: debug mroute
 570
 571    This turns on debugging for PIM interaction with kernel MFC cache.
 572
 573 .. index:: debug pim events
 574 .. clicmd:: debug pim events
 575
 576    This turns on debugging for PIM system events. Especially timers.
 577
 578 .. index:: debug pim nht
 579 .. clicmd:: debug pim nht
 580
 581    This turns on debugging for PIM nexthop tracking. It will display
 582    information about RPF lookups and information about when a nexthop changes.
 583
 584 .. index:: debug pim packet-dump
 585 .. clicmd:: debug pim packet-dump
 586
 587    This turns on an extraordinary amount of data. Each pim packet sent and
 588    received is dumped for debugging purposes. This should be considered a
 589    developer only command.
 590
 591 .. index:: debug pim packets
 592 .. clicmd:: debug pim packets
 593
 594    This turns on information about packet generation for sending and about
 595    packet handling from a received packet.
 596
 597 .. index:: debug pim trace
 598 .. clicmd:: debug pim trace
 599
 600    This traces pim code and how it is running.
 601
 602 .. index:: debug pim bsm
 603 .. clicmd:: debug pim bsm
 604
 605    This turns on debugging for BSR message processing.
 606
 607 .. index:: debug pim zebra
 608 .. clicmd:: debug pim zebra
 609
 610    This gathers data about events from zebra that come up through the ZAPI.
 611
 612 PIM Clear Commands
 613 ==================
 614 Clear commands reset various variables.
 615
 616 .. index:: clear ip interfaces
 617 .. clicmd:: clear ip interfaces
 618
 619    Reset interfaces.
 620
 621 .. index:: clear ip igmp interfaces
 622 .. clicmd:: clear ip igmp interfaces
 623
 624    Reset IGMP interfaces.
 625
 626 .. index:: clear ip mroute
 627 .. clicmd:: clear ip mroute
 628
 629    Reset multicast routes.
 630
 631 .. index:: clear ip mroute [vrf NAME] count
 632 .. clicmd:: clear ip mroute [vrf NAME] count
 633
 634    When this command is issued, reset the counts of data shown for
 635    packet count, byte count and wrong interface to 0 and start count
 636    up from this spot.
 637
 638 .. index:: clear ip pim interfaces
 639 .. clicmd:: clear ip pim interfaces
 640
 641    Reset PIM interfaces.
 642
 643 .. index:: clear ip pim oil
 644 .. clicmd:: clear ip pim oil
 645
 646    Rescan PIM OIL (output interface list).
 647
 648 PIM EVPN configuration
 649 ======================
 650 To use PIM in the underlay for overlay BUM forwarding associate a multicast
 651 group with the L2 VNI. The actual configuration is based on your distribution.
 652 Here is an ifupdown2 example::
 653
 654    auto vx-10100
 655    iface vx-10100
 656        vxlan-id 10100
 657        bridge-access 100
 658        vxlan-local-tunnelip 27.0.0.11
 659        vxlan-mcastgrp 239.1.1.100
 660
 661 .. note::
 662
 663    PIM will see the ``vxlan-mcastgrp`` configuration and auto configure state
 664    to properly forward BUM traffic.
 665
 666 PIM also needs to be configured in the underlay to allow the BUM MDT to be
 667 setup. This is existing PIM configuration:
 668
 669 - Enable pim on the underlay L3 interface via the "ip pim" command.
 670 - Configure RPs for the BUM multicast group range.
 671 - Ensure the PIM is enabled on the lo of the VTEPs and the RP.