.. _pim:

***
PIM
***

PIM -- Protocol Independent Multicast

*pimd* supports pim-sm as well as igmp v2 and v3. pim is
vrf aware and can work within the context of vrf's in order to
do S,G mrouting.  Additionally PIM can be used in the EVPN underlay
network for optimizing forwarding of overlay BUM traffic.

.. note::

   On Linux for PIM-SM operation you *must* have kernel version 4.19 or greater.
   To use PIM for EVPN BUM forwarding, kernels 5.0 or greater are required.
   OpenBSD has no multicast support and FreeBSD, and NetBSD only
   have support for SSM.

.. _starting-and-stopping-pimd:

Starting and Stopping pimd
==========================

The default configuration file name of *pimd*'s is :file:`pimd.conf`. When
invoked *pimd* searches directory |INSTALL_PREFIX_ETC|. If
:file:`pimd.conf` is not there then next search current directory.

*pimd* requires zebra for proper operation. Additionally *pimd* depends on
routing properly setup and working in the network that it is working on.

::

   # zebra -d
   # pimd -d


Please note that *zebra* must be invoked before *pimd*.

To stop *pimd* please use::

   kill `cat /var/run/pimd.pid`

Certain signals have special meanings to *pimd*.

+---------+---------------------------------------------------------------------+
| Signal  | Meaning                                                             |
+=========+=====================================================================+
| SIGUSR1 | Rotate the *pimd* logfile                                           |
+---------+---------------------------------------------------------------------+
| SIGINT  | *pimd* sweeps all installed PIM mroutes then terminates gracefully. |
| SIGTERM |                                                                     |
+---------+---------------------------------------------------------------------+

*pimd* invocation options. Common options that can be specified
(:ref:`common-invocation-options`).

.. clicmd:: ip pim rp A.B.C.D A.B.C.D/M

   In order to use pim, it is necessary to configure a RP for join messages to
   be sent to. Currently the only methodology to do this is via static rp
   commands. All routers in the pim network must agree on these values. The
   first ip address is the RP's address and the second value is the matching
   prefix of group ranges covered. This command is vrf aware, to configure for
   a vrf, enter the vrf submode.

.. clicmd:: ip pim rp keep-alive-timer (1-65535)

   Modify the time out value for a S,G flow from 1-65535 seconds at RP.
   The normal keepalive period for the KAT(S,G) defaults to 210 seconds.
   However, at the RP, the keepalive period must be at least the
   Register_Suppression_Time, or the RP may time out the (S,G) state
   before the next Null-Register arrives. Thus, the KAT(S,G) is set to
   max(Keepalive_Period, RP_Keepalive_Period) when a Register-Stop is sent.
   If choosing a value below 31 seconds be aware that some hardware platforms
   cannot see data flowing in better than 30 second chunks. This command is
   vrf aware, to configure for a vrf, enter the vrf submode.

.. clicmd:: ip pim register-accept-list PLIST

   When pim receives a register packet the source of the packet will be compared
   to the prefix-list specified, PLIST, and if a permit is received normal
   processing continues.  If a deny is returned for the source address of the
   register packet a register stop message is sent to the source.

.. clicmd:: ip pim spt-switchover infinity-and-beyond [prefix-list PLIST]

   On the last hop router if it is desired to not switch over to the SPT tree
   configure this command. Optional parameter prefix-list can be use to control
   which groups to switch or not switch. If a group is PERMIT as per the
   PLIST, then the SPT switchover does not happen for it and if it is DENY,
   then the SPT switchover happens.
   This command is vrf aware, to configure for a vrf,
   enter the vrf submode.

.. clicmd:: ip pim ecmp

   If pim has the a choice of ECMP nexthops for a particular RPF, pim will
   cause S,G flows to be spread out amongst the nexthops. If this command is
   not specified then the first nexthop found will be used. This command is vrf
   aware, to configure for a vrf, enter the vrf submode.

.. clicmd:: ip pim ecmp rebalance

   If pim is using ECMP and an interface goes down, cause pim to rebalance all
   S,G flows across the remaining nexthops. If this command is not configured
   pim only modifies those S,G flows that were using the interface that went
   down. This command is vrf aware, to configure for a vrf, enter the vrf
   submode.

.. clicmd:: ip pim join-prune-interval (1-65535)

   Modify the join/prune interval that pim uses to the new value. Time is
   specified in seconds. This command is vrf aware, to configure for a vrf,
   enter the vrf submode.  The default time is 60 seconds.  If you enter
   a value smaller than 60 seconds be aware that this can and will affect
   convergence at scale.

.. clicmd:: ip pim keep-alive-timer (1-65535)

   Modify the time out value for a S,G flow from 1-65535 seconds. If choosing
   a value below 31 seconds be aware that some hardware platforms cannot see data
   flowing in better than 30 second chunks. This command is vrf aware, to
   configure for a vrf, enter the vrf submode.

.. clicmd:: ip pim packets (1-255)

   When processing packets from a neighbor process the number of packets
   incoming at one time before moving on to the next task. The default value is
   3 packets.  This command is only useful at scale when you can possibly have
   a large number of pim control packets flowing. This command is vrf aware, to
   configure for a vrf, enter the vrf submode.

.. clicmd:: ip pim register-suppress-time (1-65535)

   Modify the time that pim will register suppress a FHR will send register
   notifications to the kernel. This command is vrf aware, to configure for a
   vrf, enter the vrf submode.

.. clicmd:: ip pim send-v6-secondary

   When sending pim hello packets tell pim to send any v6 secondary addresses
   on the interface. This information is used to allow pim to use v6 nexthops
   in it's decision for RPF lookup. This command is vrf aware, to configure for
   a vrf, enter the vrf submode.

.. clicmd:: ip pim ssm prefix-list WORD

   Specify a range of group addresses via a prefix-list that forces pim to
   never do SM over. This command is vrf aware, to configure for a vrf, enter
   the vrf submode.

.. clicmd:: ip multicast rpf-lookup-mode WORD

   Modify how PIM does RPF lookups in the zebra routing table.  You can use
   these choices:

   longer-prefix
      Lookup the RPF in both tables using the longer prefix as a match

   lower-distance
      Lookup the RPF in both tables using the lower distance as a match

   mrib-only
      Lookup in the Multicast RIB only

   mrib-then-urib
      Lookup in the Multicast RIB then the Unicast Rib, returning first found.
      This is the default value for lookup if this command is not entered

   urib-only
      Lookup in the Unicast Rib only.

.. clicmd:: ip igmp generate-query-once [version (2-3)]

   Generate IGMP query (v2/v3) on user requirement. This will not depend on
   the existing IGMP general query timer.If no version is provided in the cli,
   the default will be the igmp version enabled on that interface.

.. clicmd:: ip igmp watermark-warn (1-65535)

   Configure watermark warning generation for an igmp group limit. Generates
   warning once the configured group limit is reached while adding new groups.
   'no' form of the command disables the warning generation. This command is
   vrf aware. To configure per vrf, enter vrf submode.

.. _pim-interface-configuration:

PIM Interface Configuration
===========================

PIM interface commands allow you to configure an interface as either a Receiver
or a interface that you would like to form pim neighbors on. If the interface
is in a vrf, enter the interface command with the vrf keyword at the end.

.. clicmd:: ip pim active-active

   Turn on pim active-active configuration for a Vxlan interface.  This
   command will not do anything if you do not have the underlying ability
   of a mlag implementation.

.. clicmd:: ip pim bsm

   Tell pim that we would like to use this interface to process bootstrap
   messages. This is enabled by default. 'no' form of this command is used to
   restrict bsm messages on this interface.

.. clicmd:: ip pim unicast-bsm

   Tell pim that we would like to allow interface to process unicast bootstrap
   messages. This is enabled by default. 'no' form of this command is used to
   restrict processing of unicast bsm messages on this interface.

.. clicmd:: ip pim drpriority (1-4294967295)

   Set the DR Priority for the interface. This command is useful to allow the
   user to influence what node becomes the DR for a lan segment.

.. clicmd:: ip pim hello (1-65535) (1-65535)

   Set the pim hello and hold interval for a interface.

.. clicmd:: ip pim

   Tell pim that we would like to use this interface to form pim neighbors
   over. Please note that this command does not enable the reception of IGMP
   reports on the interface. Refer to the next `ip igmp` command for IGMP
   management.

.. clicmd:: ip pim use-source A.B.C.D

   If you have multiple addresses configured on a particular interface
   and would like pim to use a specific source address associated with
   that interface.

.. clicmd:: ip pim passive

   Disable sending and receiving pim control packets on the interface.

.. clicmd:: ip igmp

   Tell pim to receive IGMP reports and Query on this interface. The default
   version is v3. This command is useful on a LHR.

.. clicmd:: ip igmp join A.B.C.D [A.B.C.D]

   Join multicast group or source-group on an interface.

.. clicmd:: ip igmp query-interval (1-65535)

   Set the IGMP query interval that PIM will use.

.. clicmd:: ip igmp query-max-response-time (1-65535)

   Set the IGMP query response timeout value. If an report is not returned in
   the specified time we will assume the S,G or \*,G has timed out.

.. clicmd:: ip igmp version (2-3)

   Set the IGMP version used on this interface. The default value is 3.

.. clicmd:: ip multicast boundary oil WORD

   Set a pim multicast boundary, based upon the WORD prefix-list. If a pim join
   or IGMP report is received on this interface and the Group is denied by the
   prefix-list, PIM will ignore the join or report.

.. clicmd:: ip igmp last-member-query-count (1-255)

   Set the IGMP last member query count. The default value is 2. 'no' form of
   this command is used to to configure back to the default value.

.. clicmd:: ip igmp last-member-query-interval (1-65535)

   Set the IGMP last member query interval in deciseconds. The default value is
   10 deciseconds. 'no' form of this command is used to to configure back to the
   default value.

.. clicmd:: ip mroute INTERFACE A.B.C.D [A.B.C.D]

   Set a static multicast route for a traffic coming on the current interface to
   be forwarded on the given interface if the traffic matches the group address
   and optionally the source address.


.. seealso::

   :ref:`bfd-pim-peer-config`


.. _pim-multicast-rib:

PIM Multicast RIB
=================

In order to influence Multicast RPF lookup, it is possible to insert
into zebra routes for the Multicast RIB. These routes are only
used for RPF lookup and will not be used by zebra for insertion
into the kernel *or* for normal rib processing. As such it is
possible to create weird states with these commands. Use with
caution. Most of the time this will not be necessary.

.. clicmd:: ip mroute A.B.C.D/M A.B.C.D (1-255)

   Insert into the Multicast Rib Route A.B.C.D/M with specified nexthop. The
   distance can be specified as well if desired.

.. clicmd:: ip mroute A.B.C.D/M INTERFACE (1-255)

   Insert into the Multicast Rib Route A.B.C.D/M using the specified INTERFACE.
   The distance can be specified as well if desired.

.. _msdp-configuration:

Multicast Source Discovery Protocol (MSDP) Configuration
========================================================

MSDP can be setup in different ways:

* MSDP meshed-group: where all peers are connected with each other creating
  a fully meshed network. SAs (source active) messages are not forwarded in
  this mode because the origin is able to send SAs to all members.

  This setup is commonly used with anycast.

* MSDP peering: when there is one or more peers that are not fully meshed. SAs
  may be forwarded depending on the result of filtering and RPF checks.

  This setup is commonly consistent with BGP peerings (for RPF checks).

* MSDP default peer: there is only one peer and all SAs will be forwarded
  there.

.. note::

   MSDP default peer and SA filtering is not implemented.


Commands available for MSDP:

.. clicmd:: ip msdp timers (1-65535) (1-65535) [(1-65535)]

   Configure global MSDP timers.

   First value is the keep-alive interval. This configures the interval in
   seconds between keep-alive messages. The default value is 60 seconds. It
   should be less than the remote hold time.

   Second value is the hold-time. This configures the interval in seconds before
   closing a non responding connection. The default value is 75. This value
   should be greater than the remote keep alive time.

   Third value is the connection retry interval and it is optional. This
   configures the interval between connection attempts. The default value
   is 30 seconds.

.. clicmd:: ip msdp mesh-group WORD member A.B.C.D

   Create or update a mesh group to include the specified MSDP peer.

.. clicmd:: ip msdp mesh-group WORD source A.B.C.D

   Create or update a mesh group to set the source address used to connect to
   peers.

.. clicmd:: ip msdp peer A.B.C.D source A.B.C.D

   Create a regular MSDP session with peer using the specified source address.


.. _show-pim-information:

Show PIM Information
====================

All PIM show commands are vrf aware and typically allow you to insert a
specified vrf command if information is desired about a specific vrf. If no
vrf is specified then the default vrf is assumed. Finally the special keyword
'all' allows you to look at all vrfs for the command. Naming a vrf 'all' will
cause great confusion.

.. clicmd:: show ip igmp interface

   Display IGMP interface information.

.. clicmd:: show ip igmp [vrf NAME] join [json]

   Display IGMP static join information for a specific vrf.
   If "vrf all" is provided, it displays information for all the vrfs present.

.. clicmd:: show ip igmp groups

   Display IGMP groups information.

.. clicmd:: show ip igmp groups retransmissions

   Display IGMP group retransmission information.

.. clicmd:: show ip igmp [vrf NAME] sources [json]

   Display IGMP sources information.

.. clicmd:: show ip igmp sources retransmissions

   Display IGMP source retransmission information.

.. clicmd:: show ip igmp statistics

   Display IGMP statistics information.

.. clicmd:: show ip multicast

   Display various information about the interfaces used in this pim instance.

.. clicmd:: show ip mroute [vrf NAME] [A.B.C.D [A.B.C.D]] [fill] [json]

   Display information about installed into the kernel S,G mroutes.  If
   one address is specified we assume it is the Group we are interested
   in displaying data on.  If the second address is specified then it is
   Source Group.  The keyword `fill` says to fill in all assumed data
   for test/data gathering purposes.

.. clicmd:: show ip mroute [vrf NAME] count [json]

   Display information about installed into the kernel S,G mroutes and in
   addition display data about packet flow for the mroutes for a specific
   vrf.

.. clicmd:: show ip mroute vrf all count [json]

   Display information about installed into the kernel S,G mroutes and in
   addition display data about packet flow for the mroutes for all vrfs.

.. clicmd:: show ip mroute [vrf NAME] summary [json]

   Display total number of S,G mroutes and number of S,G mroutes installed
   into the kernel for a specific vrf.

.. clicmd:: show ip mroute vrf all summary [json]

   Display total number of S,G mroutes and number of S,G mroutes
   installed into the kernel for all vrfs.

.. clicmd:: show ip msdp mesh-group

   Display the configured mesh-groups, the local address associated with each
   mesh-group, the peer members included in each mesh-group, and their status.

.. clicmd:: show ip msdp peer

   Display information about the MSDP peers. That includes the peer address,
   the local address used to establish the connection to the peer, the
   connection status, and the number of active sources.

.. clicmd:: show ip pim assert

   Display information about asserts in the PIM system for S,G mroutes.
   This command does not show S,G Channel states that in a NOINFO state.

.. clicmd:: show ip pim assert-internal

   Display internal assert state for S,G mroutes

.. clicmd:: show ip pim assert-metric

   Display metric information about assert state for S,G mroutes

.. clicmd:: show ip pim assert-winner-metric

   Display winner metric for assert state for S,G mroutes

.. clicmd:: show ip pim group-type

   Display SSM group ranges.

.. clicmd:: show ip pim interface

   Display information about interfaces PIM is using.

.. clicmd:: show ip pim mlag [vrf NAME|all] interface [detail|WORD] [json]

   Display mlag interface information.

.. clicmd:: show ip pim join

   Display information about PIM joins received.  If one address is specified
   then we assume it is the Group we are interested in displaying data on.
   If the second address is specified then it is Source Group.

.. clicmd:: show ip pim local-membership

   Display information about PIM interface local-membership.

.. clicmd:: show ip pim mlag summary [json]

   Display mlag information state that PIM is keeping track of.

.. clicmd:: show ip pim neighbor

   Display information about PIM neighbors.

.. clicmd:: show ip pim nexthop

   Display information about pim nexthops that are being used.

.. clicmd:: show ip pim nexthop-lookup

   Display information about a S,G pair and how the RPF would be chosen. This
   is especially useful if there are ECMP's available from the RPF lookup.

.. clicmd:: show ip pim [vrf NAME] rp-info [A.B.C.D/M] [json]

   Display information about RP's that are configured on this router.

   You can filter the output by specifying an arbitrary group range.

   .. code-block:: frr

      # show ip pim rp-info
      RP address       group/prefix-list   OIF               I am RP    Source   Group-Type
      192.168.10.123   225.0.0.0/24        eth2              yes        Static   ASM
      192.168.10.123   239.0.0.0/8         eth2              yes        Static   ASM
      192.168.10.123   239.4.0.0/24        eth2              yes        Static   SSM

      # show ip pim rp-info 239.4.0.0/25
      RP address       group/prefix-list   OIF               I am RP    Source   Group-Type
      192.168.10.123   239.0.0.0/8         eth2              yes        Static   ASM
      192.168.10.123   239.4.0.0/24        eth2              yes        Static   SSM

.. clicmd:: show ip pim rpf

   Display information about currently being used S,G's and their RPF lookup
   information. Additionally display some statistics about what has been
   happening on the router.

.. clicmd:: show ip pim secondary

   Display information about an interface and all the secondary addresses
   associated with it.

.. clicmd:: show ip pim state

   Display information about known S,G's and incoming interface as well as the
   OIL and how they were chosen.

.. clicmd:: show ip pim [vrf NAME] upstream [A.B.C.D [A.B.C.D]] [json]

   Display upstream information about a S,G mroute.  Allow the user to
   specify sub Source and Groups that we are only interested in.

.. clicmd:: show ip pim upstream-join-desired

   Display upstream information for S,G's and if we desire to
   join the multicast tree

.. clicmd:: show ip pim upstream-rpf

   Display upstream information for S,G's and the RPF data associated with them.

.. clicmd:: show ip pim [vrf NAME] mlag upstream [A.B.C.D [A.B.C.D]] [json]

   Display upstream entries that are synced across MLAG switches.
   Allow the user to specify sub Source and Groups address filters.

.. clicmd:: show ip pim mlag summary

   Display PIM MLAG (multi-chassis link aggregation) session status and
   control message statistics.

.. clicmd:: show ip pim bsr

   Display current bsr, its uptime and last received bsm age.

.. clicmd:: show ip pim bsrp-info

   Display group-to-rp mappings received from E-BSR.

.. clicmd:: show ip pim bsm-database

   Display all fragments ofstored bootstrap message in user readable format.

.. clicmd:: mtrace A.B.C.D [A.B.C.D]

   Display multicast traceroute towards source, optionally for particular group.

.. clicmd:: show ip multicast count [vrf NAME] [json]

   Display multicast data packets count per interface for a vrf.

.. clicmd:: show ip multicast count vrf all [json]

   Display multicast data packets count per interface for all vrf.


.. seealso::

   :ref:`multicast-rib-commands`


PIM Debug Commands
==================

The debugging subsystem for PIM behaves in accordance with how FRR handles
debugging. You can specify debugging at the enable CLI mode as well as the
configure CLI mode. If you specify debug commands in the configuration cli
mode, the debug commands can be persistent across restarts of the FRR pimd if
the config was written out.

.. clicmd:: debug igmp

   This turns on debugging for IGMP protocol activity.

.. clicmd:: debug mtrace

   This turns on debugging for mtrace protocol activity.

.. clicmd:: debug mroute

   This turns on debugging for PIM interaction with kernel MFC cache.

.. clicmd:: debug pim events

   This turns on debugging for PIM system events. Especially timers.

.. clicmd:: debug pim nht

   This turns on debugging for PIM nexthop tracking. It will display
   information about RPF lookups and information about when a nexthop changes.

.. clicmd:: debug pim nht detail

   This turns on debugging for PIM nexthop in detail. This is not enabled
   by default.

.. clicmd:: debug pim packet-dump

   This turns on an extraordinary amount of data. Each pim packet sent and
   received is dumped for debugging purposes. This should be considered a
   developer only command.

.. clicmd:: debug pim packets

   This turns on information about packet generation for sending and about
   packet handling from a received packet.

.. clicmd:: debug pim trace

   This traces pim code and how it is running.

.. clicmd:: debug pim bsm

   This turns on debugging for BSR message processing.

.. clicmd:: debug pim zebra

   This gathers data about events from zebra that come up through the ZAPI.

PIM Clear Commands
==================
Clear commands reset various variables.

.. clicmd:: clear ip interfaces

   Reset interfaces.

.. clicmd:: clear ip igmp interfaces

   Reset IGMP interfaces.

.. clicmd:: clear ip mroute

   Reset multicast routes.

.. clicmd:: clear ip mroute [vrf NAME] count

   When this command is issued, reset the counts of data shown for
   packet count, byte count and wrong interface to 0 and start count
   up from this spot.

.. clicmd:: clear ip pim interfaces

   Reset PIM interfaces.

.. clicmd:: clear ip pim oil

   Rescan PIM OIL (output interface list).

.. clicmd:: clear ip pim [vrf NAME] bsr-data

   This command will clear the BSM scope data struct. This command also
   removes the next hop tracking for the bsr and resets the upstreams
   for the dynamically learnt RPs.

PIM EVPN configuration
======================
To use PIM in the underlay for overlay BUM forwarding associate a multicast
group with the L2 VNI. The actual configuration is based on your distribution.
Here is an ifupdown2 example::

   auto vx-10100
   iface vx-10100
       vxlan-id 10100
       bridge-access 100
       vxlan-local-tunnelip 27.0.0.11
       vxlan-mcastgrp 239.1.1.100

.. note::

   PIM will see the ``vxlan-mcastgrp`` configuration and auto configure state
   to properly forward BUM traffic.

PIM also needs to be configured in the underlay to allow the BUM MDT to be
setup. This is existing PIM configuration:

- Enable pim on the underlay L3 interface via the "ip pim" command.
- Configure RPs for the BUM multicast group range.
- Ensure the PIM is enabled on the lo of the VTEPs and the RP.


Sample configuration
====================

.. code-block:: frr

   debug igmp
   debug pim
   debug pim zebra

   ! You may want to enable ssmpingd for troubleshooting
   ! See http://www.venaas.no/multicast/ssmping/
   !
   ip ssmpingd 1.1.1.1
   ip ssmpingd 2.2.2.2

   ! HINTS:
   !  - Enable "ip pim ssm" on the interface directly attached to the
   !    multicast source host (if this is the first-hop router)
   !  - Enable "ip pim ssm" on pim-routers-facing interfaces
   !  - Enable "ip igmp" on IGMPv3-hosts-facing interfaces
   !  - In order to inject IGMPv3 local membership information in the
   !    PIM protocol state, enable both "ip pim ssm" and "ip igmp" on
   !    the same interface; otherwise PIM won't advertise
   !    IGMPv3-learned membership to other PIM routers

   interface eth0
    ip pim ssm
    ip igmp

