H3C Technologies H3C S10500 Series Switches - Manual (Page 99)

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To do... Use the command... Remarks
Configure multicast load splitting
multicast load-splitting { source |
source-group } Optional
Disabled by default
Configuring a multicast forwarding range
Multicast packets do not travel without a boundary in a network. The multicast data corresponding to
each multicast group must be transmitted within a definite scope.
You can configure a forwarding boundary specific to a particular multicast group on all interfaces that
support multicast forwarding. A multicast forwarding boundary sets the boundary condition for the
multicast groups in the specified range. If the destination address of a multicast packet matches the set
boundary condition, the packet will not be forwarded. After you configure an interface as a multicast
boundary, the interface can no longer forward multicast packets—including packets sent from the local
device—or receive multicast packets.
Follow these steps to configure a multicast forwarding range:
To do... Use the command... Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Configure a multicast forwarding
boundary multicast boundary group-address
{ mask | mask-length }
Required
No forwarding boundary by
default
Configuring the multicast forwarding table size
The switch maintains the corresponding forwarding entry for each multicast packet that it receives.
Excessive multicast routing entries, however, can exhaust the switch’s memory and cause lower
performance. You can set a limit on the number of entries in the multicast forwarding table based on the
networking situation and the performance requirements. If the configured maximum number of multicast
forwarding table entries is smaller than the current value, the forwarding entries in excess are not deleted
immediately. Instead, the multicast routing protocol that runs on the switch deletes them. The switch no
longer adds new multicast forwarding entries until the number of existing multicast forwarding entries
comes down below the configured value.
When forwarding multicast traffic, the switch replicates a copy of the multicast traffic for each
downstream node and forwards the traffic. Therefore, each of these downstream nodes forms a branch
of the multicast distribution tree. You can configure the maximum number of downstream nodes—namely,
the maximum number of outgoing interfaces—for a single entry in the multicast forwarding table to
lessen the burden on the switch for replicating multicast traffic. If the configured maximum number of
downstream nodes for a single multicast forwarding entry is smaller than the current number, the
downstream nodes in excess are not deleted immediately. Instead, the multicast routing protocol that runs
on the switch deletes them. The switch no longer adds new multicast forwarding entries for newly added
downstream nodes until the number of existing downstream nodes comes down below the configured
value.