9 mac address table configuration, Overview, How a mac address table entry is created – H3C Technologies H3C S7500E Series Switches User Manual

Page 112: Dynamically learning mac address entries, Mac address table configuration

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9

MAC Address Table Configuration

When configuring MAC address tables, go to these sections for information you are interested in:

Overview

Configuring a MAC Address Table

Displaying and Maintaining MAC Address Table

MAC Address Table Configuration Example

Currently, interfaces involved in MAC address table configuration can only be Layer 2 Ethernet
ports and Layer 2 aggregate interfaces.

This manual covers only the configuration of static, dynamic and blackhole unicast MAC address
table entries (source and destination). For the configuration of static multicast MAC address table
entries, refer to Multicast Routing and Forwarding Configuration and IPv6 Multicast Routing and

Forwarding Configuration

in the IP Multicast Configuration Guide.

Overview

Each entry in this table indicates the MAC address of a connected device, to which interface this
device is connected and to which VLAN the interface belongs. When forwarding a frame, the device
first looks up the MAC address table by the destination MAC address of the frame for the outgoing port.
If the outgoing port is found, the frame is forwarded rather than broadcast. Thus, broadcasts are
reduced.

How a MAC Address Table Entry Is Created

A MAC address table entry can be dynamically learned or manually configured.

Dynamically learning MAC address entries

Usually, a device can populate its MAC address table automatically by learning the source MAC
addresses of received frames.

The following is how a device learns a MAC address when it receives a frame from a port, Port A for
example:

1) Check the source MAC address (MAC-SOURCE for example) of the frame. Assume that frames

with the source MAC address MAC-SOURCE can be forwarded through Port A.

2) Look up the MAC address table by the MAC address for a match and do the following:

If an entry is found for the MAC address, update the entry.

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