MROUTED(8) System Manager's Manual (smm) MROUTED(8)

IP multicast routing daemon

mrouted [
] [
-f, --config FILE
] [
-d, --debug SYS[,SYS,...
] [
-l, --loglevel LEVEL
] [
--startup-delay SEC

mrouted is the original implementation of the Distance-Vector Multicast Routing Protocol (DVMRP), RFC 1075.
mrouted is simple to use. DVMRP is derived from RIP, RFC 1058, which means mrouted works stand-alone without any extra network setup required. You can get up and running in a matter of minutes.
mrouted maintains topological knowledge via DVMRP, upon which it implements a multicast datagram forwarding algorithm called Reverse Path Multicasting.
mrouted forwards a multicast datagrams along the shortest (reverse) path tree rooted at the subnet on which the datagram originates. The multicast delivery tree may be thought of as a broadcast delivery tree that has been pruned back so that it does not extend beyond those subnetworks that have members of the destination group. Hence, datagrams are not forwarded along those branches which have no listeners of the multicast group. The IP time-to-live of a multicast datagram can be used to limit the range of multicast datagrams.
In order to support multicasting among subnets that are separated by (unicast) routers that do not support IP multicasting, mrouted includes (built-in) support for IP-in-IP tunnels, which are virtual point-to-point links between pairs of DVMRP capable rotuers located anywhere in an internet. IP multicast packets are encapsulated for transmission through tunnels, so that they look like normal unicast datagrams to intervening routers and subnets. The encapsulation is added on entry to a tunnel, and stripped off on exit from a tunnel.
The tunneling mechanism allows mrouted to establish a virtual internet, for the purpose of multicasting only, which is independent of the physical internet, and which may span multiple Autonomous Systems. This capability is intended for experimental support of internet multicasting only, pending widespread support for multicast routing by the regular (unicast) routers. mrouted suffers from the well-known scaling problems of any distance-vector routing protocol, and does not support hierarchical multicast routing.
A more common practise today is to set up GRE tunnels between multicast capable routers and limit mrouted to run on a select number of interfaces listed in the configuration.
mrouted handles multicast routing only; there may or may not be unicast routing software running on the same machine as mrouted. With the use of tunnels, it is not necessary for mrouted to have access to more than one physical subnet in order to perform multicast forwarding.

This program follows the usual UNIX command line syntax, with long options starting with two dashes (`--'). The options are as follows:
This option enables subsystem debug messages and causes mrouted to run in the foreground of the starting terminal, regardless of the -l flag controls the (syslog) log level of each subsystem.
Available subystems:
Debug inbound/outbout packets
Pruning operations, or pruned routes
Routing messages
Detailed routing information
Neighbor gossip
Debug routing cache
Debug mrouted timer handling
Show interface (VIF) debug messages
Debug group memberships
Multicast traceroute information
Debug IGMP messages
Debug ICMP messages
Debug RSRR messages
Enable all debug messages
Specify an alternative configuration file, default /etc/mrouted.conf
Print a help message and exit.
Set log level for syslog messages: none, err, notice (default), info, debug. Use '?' for a complete list of supported log levels.
Disable all logging
Error conditions
Warning conditions
Normal but significant condition (Default)
Debug-level messages
Run in foreground, do not detach from the calling terminal. -n option. The
If an interface in /etc/mrouted.conf does not exist yet, print a warning and continue. Useful with VPN, PPP and other dynamic interfaces. However, mrouted must still be restarted to start listening on such interfaces, if they did not exist when mrouted was started.
Change mrouted default behavior and assume all interfaces are disabled unless explicitly enabled with phyint enable in /etc/mrouted.conf
Wait for DELAY seconds before applying the routes. This delay enables to exchange routes before starting to forward multicast packets and therefore eliminate transient problems at startup, at the cost of a momentary black hole. Defaults to 10 seconds.
Start mrouted in a non-pruning mode. This was previously used in routers for test purposes only. However, this is no longer supported and this option is only kept for compatibility reasons.

mrouted responds to the following signals:
Restart mrouted and reload the configuration file.
Terminate execution gracefully, i.e., by sending good-bye messages to all neighboring routers.
Same as INT.
For convenience, mrouted writes its process ID to /var/run/ when it has completed its start up and is ready to receive signals.

Main configuration file.
DVMRP generation ID. Used by neighboring DVRMP routers to detect when a router is restarted.
Pidfile (re)created by mrouted daemon when it has started up and is ready to receive commands.
UNIX-domain socket used for communication with mroutectl(8)
Holds active IPv4 multicast routes (Linux).
Holds the IPv4 virtual interfaces used by the active multicast routing daemon (Linux).

mrouted.conf(5), mroutectl(8), map-mbone(8), mrinfo(8), mtrace(8), pimd(8), smcroute(8)
S. Deering, Multicast Routing in Internetworks and Extended LANs, Proceedings of the ACM SIGCOMM '88 Conference.
The mrouted home page is ⟨⟩

The following are the principal authors of mrouted, listed in no particular order:
David Waitzman,
Craig Partridge,
Steve Deering,
Ajit Thyagarajan,
Bill Fenner,
David Thaler,
Daniel Zappala.
With contributions by many others.
Mar 28 2019 Debian