H3C Technologies H3C S12500-X Series Switches - Manual (Page 32)

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• Static entries—Static entries are manually added in order to forward frames with a specific
destination MAC address out of their associated interfaces and never age out. A static entry has
higher priority than a dynamically learned one.
• Dynamic entries—Dynamic entries can be manually configured or dynamically learned in order to
forward frames with a specific destination MAC address out of their associated interfaces and
might age out. A manually configured dynamic entry has the same priority as a dynamically
learned one.
• Blackhole entries—Blackhole entries are manually configured and never age out. Blackhole entries
are configured for filtering out frames with a specific source or destination MAC address. For
example, to block all frames destined for a specific user for security concerns, you can configure the
MAC address of this user as a blackhole MAC address entry.
• Multiport unicast entries—Multiport unicast entries are manually added in order to send frames
with a specific unicast destination MAC address out of multiple ports and never age out. A multiport
unicast entry has higher priority than a dynamically learned one.
A static, blackhole, or multiport unicast MAC address entry can overwrite a dynamic MAC address entry,
but not vice versa.
Configuring the MAC address table
The configuration tasks discussed in the following sections are all optional and can be performed in any
order.
This document covers only the configuration of unicast MAC address entries, including static, dynamic,
blackhole, and multiport unicast MAC address entries. For information about configuring static multicast
MAC address entries, see IP Multicast Configuration Guide. For information about MAC address table
configuration in VPLS, see MPLS Configuration Guide.
Configuring MAC address entries
Configuration guidelines
• When you configure a dynamic MAC address entry, if an automatically learned MAC address
entry with the same MAC address but a different outgoing interface already exists in the MAC
address table, the manually configured one overwrites the automatically learned MAC address
entry.
• The manually configured static, blackhole, and multiport unicast MAC address entries cannot
survive a reboot if you do not save the configuration. The manually configured dynamic MAC
address entries, however, are lost upon reboot whether or not you save the configuration.
A frame whose source MAC address matches different types of MAC address entries is differently
processed.
Type Description
Static MAC address entry
• Discards the frame entered on a different interface from that in the entry.
• Forwards the frame entered on the same interface with that in the entry.