H3C Technologies H3C S7500E Series Switches - Manual (Page 316)

11-6
multicast forwarding range by: Specifying boundary interfaces, which form a closed IPv6
multicast forwarding area.
You can configure the forwarding boundary for a specific IPv6 multicast group on all interfaces
that support IPv6 multicast forwarding. A multicast forwarding boundary sets the boundary
condition for the IPv6 multicast groups in the specified range. If the destination address of an
IPv6 multicast packet matches the set boundary condition, the packet will not be forwarded.
Once an IPv6 multicast boundary is configured on an interface, this interface can no longer
forward IPv6 multicast packets (including those sent from the local device) or receive IPv6
multicast packets.
Follow these steps to configure an IPv6 multicast forwarding range:
To do... Use the command... Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Configure an IPv6 multicast
forwarding boundary
multicast ipv6 boundary
ipv6-group-address
prefix-length
Required
No forwarding boundary by
default
Configuring the IPv6 Multicast Forwarding Table Size
The router maintains the corresponding forwarding entry for each IPv6 multicast packet it
receives. Excessive IPv6 multicast routing entries, however, can exhaust the router’s memory
and thus result in lower router performance. You can set a limit on the number of entries in the
IPv6 multicast forwarding table based on the actual networking situation and the performance
requirements. If the configured maximum number of IPv6 multicast forwarding table entries is
smaller than the current value, the entries in excess will not be immediately deleted; instead
they will be deleted by the IPv6 multicast routing protocol running on the router. The router will
no longer install new IPv6 multicast forwarding entries until the number of existing IPv6
multicast forwarding entries comes down below the configured value.
When forwarding IPv6 multicast traffic, the router replicates a copy of the IPv6 multicast traffic
for each downstream node and forwards the traffic, and thus each of these downstream nodes
forms a branch of the IPv6 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 IPv6 multicast forwarding table to lessen burden on the router for replicating IPv6
multicast traffic. If the configured maximum number of downstream nodes for a single IPv6
multicast forwarding entry is smaller than the current number, the downstream nodes in excess
will not be deleted immediately; instead they must be deleted by the IPv6 multicast routing
protocol. The router will no longer install new IPv6 multicast forwarding entries for newly added
downstream nodes until the number of existing downstream nodes comes down below the
configured value.