3Com Switch 8800 Advanced Software V5 Configuration Guide

510 CHAPTER 38: MULTICAST ROUTING AND FORWARDING CONFIGURATION
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Currently, Switch 8800s support multicast forwarding boundary configuration in
VLAN interface view and POS interface view.
Configuring Multicast
Forwarding Table Size
Too many multicast routing entries can exhaust the device’s memory and thus
result in lower device performance. Therefore, the number of multicast routing
entries should be limited. You can set a limit on the number of entries in the
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. This maximum value varies
with different device models.
If the configured maximum number of downstream nodes (namely, the maximum
number of outgoing interfaces) for a routing entry in the 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 multicast routing protocol. In addition, newly added downstream nodes
cannot be installed to the routing entry into the forwarding table.
If the configured maximum number of routing entries in the 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
multicast routing protocol. In addition, newly added route entries cannot be
installed to the forwarding table.
Follow these steps to configure the multicast forwarding table size:
Displaying and
Maintaining Multicast
Routing and
Forwarding
To do... Use the command... Remarks
Enter system view system-view -
Configure the maximum
number of downstream nodes
for a single route in the
multicast forwarding table
multicast forwarding-table
downstream-limit limit
Optional
128 by default
Configure the maximum
number of routing entries in
the multicast forwarding table
multicast forwarding-table
route-limit limit
Optional
512 by default
To do... Use the command... Remarks
View the multicast boundary
information
display multicast boundary [ group-address
[ mask | mask-length ] ] [ interface
interface-type interface-number ]
Available in
any view
View the multicast
forwarding table information
display multicast forwarding-table [
group-address [ mask { mask | mask-length } ]
| source-address [ mask { mask | mask-length }
] | incoming-interface { interface-type
interface-number | register } |
outgoing-interface { { include | exclude |
match } { interface-type interface-number |
register } } | statistics | slot slot-id ] * [
port-info ]
Available in
any view
Available in
any view