3com 5500-SI Manual De Usuario

C

HAPTER

 18: M

ULTICAST

 P

ROTOCOL

In Layer 2 multicast, the system can add multicast forwarding entries dynamically 
through Layer 2 multicast protocol. However, you can also manually create a static 
multicast address entry to bind a port to a multicast address.

Generally, when receiving a multicast packet whose multicast address has not yet 
been registered on the switch, the switch broadcasts the packet in the VLAN. 
However, you can configure a static multicast MAC address entry to avoid this case.

Table 322 describes how to configure a multicast MAC address entry.

You can use the corresponding undo command to cancel the creation.

Note that:

■

If the multicast MAC address entry you are creating has already been existed, the 
system gives you a prompt.

■

The switch will not learn a manually added multicast MAC address by IGMP 
Snooping. The undo mac-address multicast command can only remove 
manually created multicast MAC address entries and cannot remove those learned 
by the switch.

■

When adding a port to a manually created multicast MAC address entry, you 
should first remove the entry, then re-create the entry and specify the port as the 
forward port of the entry.

■

The system does not support the configuring of multicast MAC address on an IRF 
port. If you do this, the system will give you a prompt that the multicast MAC 
address configuration fails.

■

You cannot enable port aggregation on a port where you have configured a 
multicast MAC address; and you cannot configure a multicast MAC address on an 
aggregated port.

You can use the following display command in any view to display the multicast 
MAC address entry configuration.

Table 322   Configure a multicast MAC address entry

Enter system view

system-view

—

Add a multicast MAC address 
entry

mac-address multicast 
mac-address interface 
interface-list  vlan vlan-id

Required
mac-address must be a 
multicast MAC address.

vlan-id is the VLAN ID the port 
belongs to.

Enter Ethernet port view

interface interface-type 
interface-number

—

Add a multicast MAC address 
entry.

mac-address multicast 
mac-address  vlan vlan-id

Required
This command is used in 
Ethernet port view. It has the 
same effect with the above 
command used in system view 
with the same port specified.

Table 323   Display multicast MAC address configuration

Display all the multicast MAC 
address entries added

display mac-address 
multicast static [ count | 
mac-address vlan vlan-id | 
vlan vlan-id ]

You can use the display 
command in any view.