3Com Switch 4800G 24-Port Configuration Manual page 708

708 C 49: M
HAPTER ULTICAST
Configuring the
Multicast Forwarding
Table Size
Tracing a Multicast Path
R F C
OUTING AND ORWARDING
To do...
Enter system view
Enter interface view
Configure a multicast
forwarding boundary
Too many multicast routing entries can exhaust the router's memory and thus
result in lower router 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:
To do...
Enter system view
Configure the maximum number
of downstream nodes for a single
route in the multicast forwarding
table
Configure the maximum number
of routing entries in the multicast
forwarding table
You can run the mtracert command to trace the path down which the multicast
traffic flows from a given multicast source to the last-hop router for
troubleshooting purposes.
To do...
Trace a multicast path
ONFIGURATION
Use the command...
system-view
interface interface-type
interface-number
multicast boundary
group-address { mask |
mask-length }
Use the command...
system-view
multicast forwarding-table
downstream-limit limit
multicast forwarding-table
route-limit limit
Use the command...
mtracert source-address
[ [ last-hop-router-address ]
group-address ]
Remarks
-
-
Required
No forwarding boundary by
default
Remarks
-
Optional
The default is 128.
Optional
The default is 1024.
Remarks
Required
Available in any view