H3C Technologies H3C S12500 Series Switches - Manual (Page 351)

335
Configuring an IPv6 multicast forwarding range
IPv6 multicast packets do not travel infinitely in a network. The IPv6 multicast data of each IPv6 multicast
group must be transmitted within a definite scope. You can define an IPv6 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 or an IPv6 multicast group
with the scope field in its group address being specified 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) nor receive IPv6 multicast packets.
To configure an IPv6 multicast forwarding boundary:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A
3. Configure an IPv6 multicast
forwarding boundary.
multicast ipv6 boundary
{ ipv6-group-address prefix-length
| scope { scope-id | admin-local |
global | organization-local |
site-local } }
No forwarding boundary by
default.
Configuring the IPv6 multicast forwarding table size
The router maintains the corresponding forwarding entry for each IPv6 multicast packet that it receives.
However, excessive IPv6 multicast routing entries can exhaust the router's memory and cause 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, the IPv6 multicast routing protocol that running on the router will delete
them. The router will no longer install new IPv6 multicast forwarding entries until the number of existing
IPv6 multicast forwarding entries comes down under 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 (the maximum number of outgoing
interfaces) for a single entry in the IPv6 multicast forwarding table to lessen the 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, the IPv6 multicast routing protocol will delete them. The router will
no longer create new IPv6 multicast forwarding entries for newly added downstream nodes until the
number of existing downstream nodes decreases.
To configure the IPv6 multicast forwarding table size: