VLANs

VLANs allow you to split your physical LAN into logical subparts, providing an essential tool for increasing the efficiency and flexibility of your network.

Overview

Each defined VLAN behaves as its own separate network, with its traffic and broadcasts isolated from the other VLANs to increase bandwidth efficiency within each logical group. One example of how VLANs can be used to segment a LAN is when isolating different types of network traffic. If you wanted to utilize Jumbo Frames on a portion of your LAN, you could configure one VLAN for devices that support Jumbo Frames, and a separate VLAN for devices supporting only standard frames. By implementing VLANs, you could segregate the different frame types from each other without reorganizing your LAN into separate physical subnets.

Although VLANs are commonly used to create individual broadcast domains and/or separate IP subnets, it is sometimes useful for a server to have a presence on more than one VLAN simultaneously. Alteon WebSystems switches and ITI5100G/GF adapters support multiple VLANs on a per-port or per-interface basis, allowing very flexible network configurations.

See Figure 6 for an example of servers supporting multiple VLANs with Tagging.

VLAN #1

VLAN #2

VLAN #3

Accounting Server

(VLAN #3)Main Server

(All VLANs)

ITI5100G Gigabit

VLAN Tagged

Shared

Media Segment

PC #1

PC #2

 

PC #3

 

PC #4

 

PC #5

Software Dept.

Software Dept.

 

Engineering

 

Accounting

 

Engineering/Software

(VLAN #2)

(VLAN #2)

 

(VLAN #1)

 

(VLAN #3)

 

(VLAN #1 & #2)

 

 

 

 

 

 

 

ITI5100G Gigabit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VLAN Tagged

Figure 6: Servers Supporting Multiple VLANs

 

 

 

 

LSI Logic Corporation

 

 

 

 

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