Allied Telesis AT-2972T/2 - Manual (Page 110)

Key Protocols and Interfaces
110
Figure 14 on page 109 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. The features of this network are
described in Table 5.
Table 5. 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, PCs 1 and 2 via 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 an
AT-29xxSX Series Gigabit Ethernet adapter installed.
All three IP subnets are accessed via the single
physical adapter interface. The server is attached to
one of the switch ports, which is configured for VLANs
1, 2, and 3. Both the adapter and the connected
switch port have tagging turned on. Because of the
tagging VLAN capabilities of both devices, the server
is able to communicate 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 to VLAN
2 only 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’s switch port.
PC 4 A member of VLAN 3, PC 4 can only communicate
with the servers. Tagging is not enabled on PC 4’s
switch port.