H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 56)

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7
VLAN Configuration
The term switch in this document refers to a switch in a generic sense or an access controller
configured with the switching function unless otherwise specified.
When configuring VLAN, go to these sections for information you are interested in:
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Introduction to VLAN
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Configuring Basic VLAN Attributes
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Basic VLAN Interface Configuration
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Port-Based VLAN Configuration
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MAC Address-Based VLAN Configuration
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Displaying and Maintaining VLAN
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VLAN Configuration Example
Introduction to VLAN
VLAN Overview
Ethernet is a network technology based on the Carrier Sense Multiple Access/Collision Detect
(CSMA/CD) mechanism. As the medium is shared in an Ethernet, network performance may degrade
as the number of hosts on the network is increasing. If the number of the hosts in the network reaches a
certain level, problems caused by collisions, broadcasts, and so on emerge, which may cause the
network operating improperly. In addition to the function that suppresses collisions (which can also be
achieved by interconnecting LANs), virtual LAN (VLAN) can also isolate broadcast packets. VLAN
divides a LAN into multiple logical LANs with each being a broadcast domain. Hosts in the same VLAN
can communicate with each other like in a LAN. However, hosts from different VLANs cannot
communicate directly. In this way, broadcast packets are confined to a single VLAN, as illustrated in the
following figure.