diff options
Diffstat (limited to 'usr.sbin/mrouted/mrouted.8')
| -rw-r--r-- | usr.sbin/mrouted/mrouted.8 | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/usr.sbin/mrouted/mrouted.8 b/usr.sbin/mrouted/mrouted.8 index 2aad223..1e56452 100644 --- a/usr.sbin/mrouted/mrouted.8 +++ b/usr.sbin/mrouted/mrouted.8 @@ -23,12 +23,15 @@ datagram forwarding algorithm called Reverse Path Multicasting. .Pp .Nm Mrouted forwards a multicast datagram along a shortest (reverse) path tree -rooted at the subnet on which the datagram originates. The multicast +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 +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 +multicast group. +The IP time-to-live of a multicast datagram can be used to limit the range of multicast datagrams. .Pp In order to support multicasting among subnets that are separated by (unicast) @@ -74,7 +77,8 @@ in order to perform multicast forwarding. The following options are available: .Bl -tag -width indent .It Fl c Ar config_file -Specify an alternative file for configuration commands. Default is +Specify an alternative file for configuration commands. +Default is .Pa /etc/mrouted.conf . .It Fl d Op Ar debug_level If no @@ -291,7 +295,8 @@ traffic. It defaults 0 (unlimited). .It boundary Ar "boundary-name|scoped-addr/mask-len" The boundary option allows an interface to be configured as an administrative boundary for the specified -scoped address. Packets belonging to this address will not +scoped address. +Packets belonging to this address will not be forwarded on a scoped interface. The boundary option accepts either a name or a boundary spec. This command may be specified several times on an interface in order to describe multiple boundaries. @@ -493,8 +498,10 @@ instance of .Nm is the one responsible for sending periodic group membership queries on the vif 0 and vif 1 subnets, as indicated by the -"querier" flags. The list of boundaries indicate the scoped addresses on that -interface. A count of the no. of incoming and outgoing packets is also +"querier" flags. +The list of boundaries indicate the scoped addresses on that +interface. +A count of the no. of incoming and outgoing packets is also shown at each interface. .Pp Associated with each subnet from which a multicast datagram can originate @@ -507,7 +514,8 @@ origin, and a multicast datagram from that origin will be forwarded on that outgoing vif only if there are members of the destination group on that leaf. .Pp .Nm Mrouted -also maintains a copy of the kernel forwarding cache table. Entries +also maintains a copy of the kernel forwarding cache table. +Entries are created and deleted by .Nm mrouted . .Pp @@ -545,16 +553,21 @@ amount of time until the upstream prune will time out. The 'Ivif' field indicates the incoming vif for multicast packets from that origin. Each router also maintains a record of the number of prunes received from neighboring -routers for a particular source and group. If there are no members of +routers for a particular source and group. +If there are no members of a multicast group on any downward link of the multicast tree for a -subnet, a prune message is sent to the upstream router. They are +subnet, a prune message is sent to the upstream router. +They are indicated by a "P" after the vif number. .Pp The Forwvifs field shows the interfaces along which datagrams belonging to the source-group are -forwarded. A "p" indicates that no datagrams are being forwarded along -that interface. An unlisted interface is a leaf subnet with no -members of the particular group on that subnet. A "b" on an interface +forwarded. +A "p" indicates that no datagrams are being forwarded along +that interface. +An unlisted interface is a leaf subnet with no +members of the particular group on that subnet. +A "b" on an interface indicates that it is a boundary interface, i.e. traffic will not be forwarded on the scoped address on that interface. .Pp |
