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VLAN Overview 243
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Using the Spanning Tree algorithm in switching devices to control the
flow of traffic among LANs (for redundant links). These mechanisms
work best only in certain types of LAN topologies.
VLAN technology provides a high-performance and easy-to-implement
alternative to routers for broadcast containment. When you use
switching devices with VLANs:
■
Each network segment can contain as few as one user (approaching
private-port LAN switching), while broadcast domains can be as large
as 1,000 users, or even more.
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VLANs can help network administrators track workstation movements
to new locations without manual reconfiguration of IP addresses.
■
VLANs can be used to isolate unicast traffic to a single broadcast
domain, thereby providing a form of network security.
Benefits You can use VLANs to:
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Reduce the cost of equipment moves, upgrades, and other changes
and simplify network administration.
■
Create virtual workgroups in which members of the same department
or section appear to share the same LAN, with most of the network
traffic staying in the same VLAN broadcast domain. They can isolate
broadcast and multicast traffic to a single broadcast domain, as well as
unicast traffic.
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Help avoid flooding and minimize broadcast and multicast traffic.
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Reduce the need for routing to achieve higher network performance,
ease of administration, and reduced costs.
■
Control communication among broadcast domains.
VLANs on the
Switch 4007
Your system offers a collection of modules that pass traffic to one another
using a central switch called the Gigabit Ethernet (GEN) Switch Fabric
Module. This switch fabric module, operating at Layer 2, controls the
Ethernet traffic associated with its modules.
The switch fabric module supports a variety of Layer 2 Switching
Modules, Multilayer Switching Modules, and Interface Modules. See the
Switch 4007 Getting Started Guide for a list of supported modules.