Configuring A Multicast Forwarding Range - HP A8800 Configuration Manual

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. Currently, you can define a multicast
forwarding range by specifying boundary interfaces, which form a closed multicast forwarding area.
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. Once a multicast boundary is configured on an
interface, this interface can no longer forward multicast packets (including packets sent from the local
device) or receive multicast packets.
To configure a multicast forwarding range:
Step
1. Enter system view.
2. Enter interface view.
3. Configure a multicast
forwarding boundary.
Configuring the multicast forwarding table size
The router maintains the corresponding forwarding entries for each multicast data packet it receives.
Excessive 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 multicast forwarding table based
on the actual networking situation and the performance requirements.
If the configured maximum number of multicast forwarding entries is smaller than the current value, the
forwarding entries in excess will not be deleted immediately; instead they will be deleted by the multicast
routing protocol running on the router. The router will no longer add new multicast forwarding entries
until the number of existing multicast forwarding entries comes down below the configured value.
When forwarding multicast traffic, the router replicates a copy of the multicast traffic for each
downstream node and forwards the traffic, so 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
burden on the router 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 will not be deleted immediately; instead they will be deleted by the multicast routing protocol.
The router will no longer add new multicast forwarding entries for newly added downstream nodes until
the number of existing downstream nodes comes down below the configured value.
Configuring the multicast forwarding table size on the public network
Step
1. Enter system view.
Command
system-view
interface interface-type
interface-number
multicast boundary group-address
{ mask | mask-length }
Command
system-view
69
Remarks
N/A
N/A
No forwarding boundary by
default.
Remarks
N/A