Protocol Multicast-Mac Enable - 3Com 7750 Series Command Reference Manual

3Com Switch 7750 Series
Command Reference Guide – Routing Protocol
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3.1.44 protocol multicast-mac enable

Syntax
protocol multicast-mac enable
undo protocol multicast-mac enable
View
System view
Parameter
None
Description
Use the protocol multicast-mac enable command to enable protocol multicast MAC
address delivery. Use the undo protocol multicast-mac enable command to
disable protocol multicast MAC address delivery.
By default, protocol multicast MAC address delivery is enabled.
If OSPF is configured when Layer 2/Layer 3 multicast function is enabled in the
system, the system will multicast the broadcast routing protocol packets because the
broadcast MAC address and multicast MAC address used by the delivered OSPF
routing protocol are the same. This makes broadcast packets unable to reach the
destination host and adversely affects the running of the routing protocol.
You can disable the protocol multicast MAC address delivery function so that the
system correctly forwards OSPF multicast packets, thus ensuring the normal running
of the routing protocol.
Note:
Disable protocol multicast MAC address delivery (with the undo protocol
multicast-mac enable command) only if you are configuring OSPF with Layer
2/Layer 3 multicast function enabled in the system.
You do not need to disable protocol multicast MAC address delivery if the system
is enabled with OSPF only.
Chapter 3 OSPF Configuration Commands
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