pimdd.conf —
pimdd configuration file
In many cases you do not need to configure
pimdd. It configures itself automatically
to forward multicast on all multicast-capable interfaces, i.e., interfaces
that have the
IFF_MULTICAST flag set. It
locates other PIM-DM capable routers directly reachable via those interfaces.
pimdd will not start with less than two
enabled virtual interfaces (VIFs). A VIF is either a physical
multicast-capable interface or a tunnel. To override the default settings, for
example to disable some interfaces from being used, configuration commands may
be placed in
/etc/pimdd.conf.
The file format is relatively free-form: whitespace (including newlines) is not
significant. However, the order of some statements are important, more on this
below.
By default,
pimdd runs on all multicast
capable interfaces. The
phyint setting can
be used to control this behavior.
The PIM assert mechanism arbitrates the forwarder of multicast when there are
more than one router with the same (S,G) pair for a given destination LAN. The
winner of an assert is the router with either the best (unicast) protocol
distance (called metric preference in the RFC), or the best metric if the
distance is the same, or, as a tiebreaker, the highest IP address. The loser
of an asser election prunes its outbound interface from forwarding and starts
an assert timer, in case the active forwarder is lost. The
assert-timeout can be used to tune the PIM
assert timer to a value between 5 to 210 seconds, default: 180 sec.
The
default-route-distance option has nothing
to do with the system default route, it is rather the default value for the
unicast routing protocol's administrative distance. It is used in PIM Assert
elections to determine upstream routers. Currently
pimdd.conf cannot obtain the admin distance
and metric from the unicast routing protocols, so a default routing protocol
distance (the RFC confusingly refers to this as
metric prefererence) may be configured. In a PIM
Assert election, the router advertising the lowest assert preference will be
selected as the forwarder and upstream router for the LAN. Setting 101 should
be sufficiently high so that asserts from Cisco or other routers preferred
over
pimdd.conf.
It is recommended that distances be set such that metrics are never consulted.
However, default routing metrics may also be set using the
default-route-metric option. (Again, this
has nothing to do with the system default route.) This item sets the cost for
sending data through this router. You want only PIM-DM data to go to this
daemon; so once again, a high value is recommended to prevent accidental
usage. The preferred default value is 1024. Both defaults can be overridden
per phyint, so learned routes, or PIM Asserts use the phyint's values.
Please also note that PIM Assert elections are not the same as the DR election.
The PIM Assert election determines the active multicast forwarder, whereas the
DR election determines the active PIM router.
The
phyint setting refers to a physical
interface and must come after the
default-route-metric and
default-route-distance settings in the
configuration file. Select the interface by its IP
address or name. If you just want to activate
this interface with default values, you don't need to put anything else on the
line. However, there are some additional settings:
enable:
Enable an interface for PIM. Used after the no
phyint directive.disable:
Do not use this interface in
pimdd.conf.igmpv2
|
igmpv3:
Force interface in specific IGMP version. Default:
igmpv3.distance
⟨1-255⟩: Use this to
override the default-route-distance
(101) on this phyint in PIM Assert
elections.metric
⟨1-1024⟩: The cost of
sending data through this interface. Defaults to
default-route-metric (1024) if not
assigned.
Add one
phyint line per interface on this
router. Otherwise
pimdd.conf will run on
all interfaces using default settings.
- /etc/pimdd.conf
- Main configuration file.
pimdd(8),
pimctl(8)
This manual page was written by
Joachim
Wiberg ⟨mailto:troglobit@gmail.com⟩.