HP-UX Routing Services Administrator's Guide HP-UX 11i v2, HP-UX 11i v3 (B2355-91153, November 2011)

replace the remote IP address, remote-addr, by a host name, but only if the host name has a
single IP address associated with it. Before you can use a tunnel, it must be set up in the mrouted
configuration files of both the mrouted routers participating in the tunnel. mrouted 3.8 does not
support the srcrt option. (It provided backward compatibility with older versions of mrouted
that implemented IP multicast datagram encapsulation using IP source routing.)
NOTE: A phyint command must precede a tunnel command. All the phyint and tunnel
command options must be placed on a single line except for the boundary and altnet options,
which can begin on a separate line.
Figure 3 Multicast Network Example Configuration
The metric is the cost, or overhead, associated with sending a datagram on the given interface
or tunnel, and is used primarily to influence the choice of routes over which the datagram is
forwarded; the larger the value, the higher the cost. You must keep metrics as small as possible,
because mrouted cannot route along paths with metrics greater than 31. In general, use a metric
value of 1 for all links unless you are specifically attempting to force traffic to take another route.
In this case, the metric of the alternate path should be the sum of the metrics on the primary path
+ 1. The default metric value is 1.
The threshold is the minimum IP time-to-live (TTL) required for a multicast datagram to be
forwarded to a given interface or tunnel. It controls the scope of multicast datagrams. If the TTL
value in the datagram is less than the threshold value, the datagram is dropped; if the TTL is
greater than or equal to the threshold value, the packet is forwarded. The default threshold
value is 1.
The TTL value of forwarded packets is only compared with the threshold value; it is not
decremented by the threshold. An application that initiates the IP multicast datagram sets the
TTL, and typically represents the number of subnets, or hops, the datagram has to traverse to reach
its destination. Every time a multicast datagram passes through a multicast router, the TTL value is
decremented by 1. HP recommends that you use the default threshold value unless you have a
specific reason to set it otherwise.
In general, all interfaces connected to a particular subnet or tunnel should use the same metric
and threshold values for that subnet or tunnel.
You can use the rate_limit option to specify a certain bandwidth in Kbits/second which is
allocated to multicast traffic. The default value is 500Kbps on tunnels and 0 (unlimited) on physical
interfaces.
You can use the boundary option to configure an interface as an administrative boundary for the
specified boundary-name or scoped-addr (scoped address). You can specify more than one
boundary option in the phyint and tunnel commands. Packets belonging to the scoped address,
which is an IP multicast group address, are not forwarded on this interface.mask-len indicates
the number of leading 1s in the mask applied (by means of a bitwise logically AND operation) to
the scoped address. For example, the statement boundary 239.2.3.3/16 would result in the
mask 255.255.0.0 being calculated by means of an AND operation with 239.2.3.3 to isolate
the first two octets, 239.2, of the scoped address. Therefore, all IP multicast addresses beginning
with 239.2 will not be forwarded on the specified interface.
How to Configure mrouted 15