Installing and Administering Internet Services

398 Chapter9

Conﬁguring mrouted

The primary use of the boundary option is to allow concurrent use of the

same IP multicast address(es) on downstream subnets without

interfering with multicast broadcasts using the same IP multicast

address(es) on subnets that are upstream from the mrouted gateway.

The cache_lifetime value determines the amount of time that a cached

multicast route remains in the kernel before timing out. This value is

speciﬁed in seconds and should be between 300 (5 minutes) and 86400

(24 hours). The default value is 300.

The pruning off command explicitly conﬁgures mrouted to act as a

“non-pruning” router. When pruning is off, IP multicast datagrams are

forwarded to leaf subnets of the broadcast routing tree even when those

leaf subnets do not contain members of the multicast destination group.

Non-pruning mode should be used only for testing. The default mode for

pruning is on.

The name command enables you to assign a name (

boundary-name

) to a

boundary (a

scoped-addr

mask-len

pair), which can make

conﬁguration easier.

mrouted will terminate execution if it has less than two enabled virtual

interfaces (vifs), where a vif is either a physical multicast-capable

interface or a tunnel. It logs a warning if all of its vifs are tunnels. If this

happens, we recommend that you replace that conﬁguration with more

direct tunnels.