Users Guide

3–Virtual LANs in Windows
VLAN Overview
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Figure 3-1 shows an example network that uses VLANs. In this example network,
the physical LAN consists of a switch, two servers, and five clients. The LAN is
logically organized into three different VLANs, each representing a different IP
subnet. Table 3-1 describes the features of this network.
Table 3-1. Example VLAN Network Topology
Component Description
VLAN #1 An IP subnet consisting of the Main Server, PC #3, and PC #5. This
subnet represents an engineering group.
VLAN #2 Includes the Main Server, PC #1 and PC #2 through shared media
segment, and PC #5. This VLAN is a software development group.
VLAN #3 Includes the Main Server, the Accounting Server, and PC #4. This
VLAN is an accounting group.
Main Server A high-use server that needs to be accessed from all VLANs and IP
subnets. The Main Server has a QLogic adapter installed. All three
IP subnets are accessed through the single physical adapter inter-
face. The server is attached to one of the switch ports, which is con-
figured for VLANs #1, #2, and #3. Both the adapter and the
connected switch port have tagging turned on. Because of the tag-
ging VLAN capabilities of both devices, the server is able to com-
municate on all three IP subnets in this network, but continues to
maintain broadcast separation between all of them.
Accounting
Server
Available to VLAN #3 only. The Accounting Server is isolated from
all traffic on VLANs #1 and #2. The switch port connected to the
server has tagging turned off.
PCs #1 and #2 Attached to a shared media hub that is then connected to the
switch. PCs #1 and #2 belong only to VLAN #2, and are logically in
the same IP subnet as the Main Server and PC #5. The switch port
connected to this segment has tagging turned off.
PC #3 A member of VLAN #1, PC #3 can communicate only with the Main
Server and PC #5. Tagging is not enabled on PC #3 switch port.
PC #4 A member of VLAN #3, PC #4 can only communicate with the serv-
ers. Tagging is not enabled on PC #4 switch port.
PC #5 A member of both VLANs #1 and #2, PC #5 has a QLogic adapter
installed. It is connected to switch port #10. Both the adapter and
the switch port are configured for VLANs #1 and #2 and have tag-
ging enabled.