3Com Switch 8800 Advanced Software V5 Configuration Guide

Configuring IPv6 Multicast Routing and Forwarding 519
Presently, 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 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:
Configuring the IPv6
Multicast Forwarding
Table Size
Too many IPv6 multicast routing entries can exhaust the device’s memory and thus
result in lower device performance. Therefore, the number of IPv6 multicast
routing entries should be limited. You can set a limit on the number of entries in
the IPv6 multicast routing table based on the actual networking situation and the
performance requirements. In any case, the number of route entries must not
exceed the maximum number allowed by the system.
If the configured maximum number of downstream nodes (namely the maximum
number of outgoing interfaces) for a routing entry in the IPv6 multicast forwarding
table is smaller than the current number, the downstream nodes in excess of the
configured limit will not be deleted immediately; instead they must be deleted by
the IPv6 multicast routing protocol. In addition, newly added downstream nodes
cannot be installed to the routing entry in the forwarding table.
If the configured maximum number of routing entries in the IPv6 multicast
forwarding table is smaller than the current number, the routes in excess of the
configured limit will not be deleted immediately; instead they must be deleted by
the IPv6 multicast routing protocol. In addition, newly added routing entries
cannot be installed to the forwarding table.
Follow these steps to configure the IPv6 multicast forwarding table size:
To do... Use the command... Remarks
Enter system view system-view -
Enter VLAN 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
To do... Use the command... Remarks
Enter system view system-view -
Configure the maximum
number of downstream nodes
for a single route in the IPv6
multicast forwarding table
multicast ipv6
forwarding-table
downstream-limit limit
Optional
128 by default