pimd is a lightweight, stand-alone implementation of RFC 2362, available under the 3-clause BSD license. This is the restored original version from University of Southern California, by Ahmed Helmy, Rusty Eddy and Pavlin Ivanov Radoslavov.
pimd is maintained at GitHub. Use its facilities to access the source, report bugs, feature requests, send patches and for GIT pull requests:
pimd also has a homepage, mainly to distribute releases:
pimd is primarily developed on Linux and should work as-is out of the
box on all major distributions. Other UNIX variants should also work,
but are not as thoroughly tested. For some tips and details, see the
When building pimd from source you first need to run the
script to generate the file
config.mk. The script relies on Bourne
shell standard features as well as expr and uname. Any optional pimd
features, such as
--enable-scoped-acls are activated here as well.
./configure --enable-scoped-acls make sudo make install
The Makefile supports de facto standard environment variables such as
DESTDIR for the install process. E.g., to install pimd
/usr instead of the default
/usr/local, but redirect to a binary
package directory in
VERSION=2.2.0-1 prefix=/usr DESTDIR=/tmp/pimd-2.2.0-1 make clean install
The configuration is kept in the file
/etc/pimd.conf, the order of
the statements are in some cases important.
PIM-SM is a designed to be a protocol independent multicast routing protocol. As such it relies on protocols like, e.g, OSPF, RIP, or static routing entries, to figure out the path to all multicast capable neighboring routers. This information is necessary in setups with more than one route between a multicast sender and a receiver to figure out which PIM router should be the active forwarder.
However, pimd currently cannot retrieve the unicast routing distance (preference) and metric of routes from the system, not from the kernel nor a route manager like zebra. Hence, pimd currently needs to be setup statically on each router using the desired distance and metric for each active interface. If either the distance and/or the metric is missing in an interface configuration, the following two defaults will be used:
default_source_preference <1-255> default: 101 (distance) default_source_metric <1-1024> default: 1024
By default pimd starts up on all interfaces it can find, using the above defaults. To configure individual interfaces use:
phyint <address | ifname> ...
You can reference the interface via either its local IPv4 address or its name, e.g., eth0. Some common interface settings are:
disable: Disable pimd on this interface, i.e., do not send or listen for PIM-SM traffic
preference <1-255>: The interface's distance value (also confusingly referred to as metric preference) in PIM Assert messages. Used with
metricto elect the active multicast forwarding router. Defaults to
metric <1-1024>: The cost for traversing this router. Used with the
preferencevalue above. Defaults to
More interface settings are available, see the pimd(8) manual page for the full details.
The most notable feature of PIM-SM is that multicast is distributed from
so called Rendezvous Points (RP). Each RP handles distribution of one
or more multicast groups, pimd can be configured to advertise itself as
a candidate RP
cand_rp, and request to be static RP
one or more multicast groups.
rp_address <address> [<group>[/<LENGTH> | masklen <LENGTH]
rp_address setting is the same as the Cisco
ip pim rp-address
setting to configure static Rendezvous Points. The first argument can
be an IPv4 address or a multicast group address. The default group and
prefix length is 184.108.40.206/16. Static RP's always have priority 1.
cand_rp [address | ifname] [time <10-16383>] [priority <0-255>]
The Rendezvous Point candidate, or CRP, setting is the same as the Cisco
ip pim rp-candidate setting. Use it to control which interface that
should be used in RP elections.
address | ifname: Optional local IPv4 address, or interface name to acquire address from. The default is to use the highest active IP address.
time <10-16383>: The interval, in seconds, between advertising this CRP. Default: 60 seconds
priority <0-255>: How important this CRP is compared to others. The lower the value here, the more important the CRP. Like Cisco, pimd defaults to priority 0 when this is left out
In the CRP messages sent out by pimd, one or more multicast groups can be advertised using the following syntax.
group_prefix <group>[</LENGTH> | masklen <LENGTH>]
group_prefix setting defines one multicast group and an optional
mask length, which defaults to 16 if left out. A maximum of 255
multicast group prefix records is possible for the CRP.
To keep track of all Rendezvous Points in a PIM-SM domain there exists a feature called Bootstrap Router. The elected BSR in a PIM-SM domain periodically announces the RP set in Bootstrap messages. For details on PIM BSR operation, see RFC 5059.
cand_bootstrap_router [address | ifname] [priority <0-255>]
The configuration of a Candidate BootStrap Router (CBSR) is very similar to that of CRP, except for the interval time. If either the address or the interface name is left out pimd uses the highest active IP address. If the priority is left out, pimd (like Cisco) defaults to priority 0.
In a PIM-SM domain there can be two, or more, paths from a designated router (DR) for a multicast sender to reach a receiver. When receivers begin joining multicast groups all data is received via the shared tree (RPT) from each Rendezvous Point (RP). This is often not an optimal route, so when the volume starts exceeding a configurable threshold, on either the last-hop router or the RP itself, the router will attempt to switch to the shortest path tree (SPT) from the multicast source to the receiver.
In versions of pimd prior to 2.2.0 this threshold was confusingly split in two different settings, one for the DR and one for the RP. These settings are still supported, for compatibility reasons and documented in the man-page, but it is strongly recommended to change to the new syntax instead:
spt_threshold [rate <KBPS> | packets <NUM> | infinity] [interval <5-60>]
Only slightly different from the Cisco
ip pim spt-threshold setting,
pimd can trigger a switch to SPT on a rate or number of packets and you
can also tweak the poll interval. It's recommended to keep the interval
in the tens of seconds, the default is 100 sec. The default threshold
is set to zero packets, which will cause a switch over to the SPT after
the first multicast packet is received.
# This pimd.conf example assumes a router with four interfaces. # Interface eth0 is disabled, i.e., pimd will not run there. # The default interface preference 101 has been changed on all # the other interfaces. phyint eth0 disable phyint eth1 preference 255 phyint eth2 preference 250 phyint eth3 preference 251 # Offer to be an RP for all of 220.127.116.11/4 cand_rp eth1 group_prefix 18.104.22.168 masklen 4 # Partake in BSR elections as well cand_bootstrap_router eth1 # This is the built-in defaults, switch to SPT on first packet spt_threshold packets 0 interval 100
Having set up the configuration file, you are ready to run pimd. As usual, it is recommended that you start it manually first, to make sure everything works as expected, before adding it to your system's startup scripts, with any startup flags it might need.
pimd [-c file] [-d[level1,...,levelN]]
-c file: Utilize the specified configuration file rather than the default,
-d[level1,...,levelN]: Specifies the debug level(s) to utilize when running the daemon. Type
pimd -hfor a full list of levels
pimd -c /cfg/pimd.conf -digmp_proto,pim_jp,kernel,pim_register
Notice the lack of spaces in the option argument to
To see the virtual interface table, including neighboring PIM routers, and the multicast routing table:
or to watch it continually:
watch pimd -r
In addition, pimd logs important events to the system logfile, in
particular at startup when parsing the
pimd.conf configuration file.