Chapter 1 Vlan Configuration; Introduction To Vlan; Vlan Overview - H3C S5500-SI Series Operation Manual

Operation Manual – VLAN
H3C S5500-SI Series Ethernet Switches

Chapter 1 VLAN Configuration

When configuring VLAN, go to these sections for information you are interested in:

Introduction to VLAN

Configuring Basic VLAN Attributes
Basic VLAN Interface Configuration
Port-Based VLAN Configuration
MAC Address-Based VLAN Configuration
Displaying and Maintaining VLAN
VLAN Configuration Example
1.1 Introduction to VLAN

1.1.1 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.
Figure 1-1 A VLAN diagram
1-1
Chapter 1 VLAN Configuration