Allied Telesis AT-S39 User Manual

Page 104

Section II: Local and Telnet Management

104

The port assignments for the VLANs are as follows:

This example is nearly identical to the Port-based Example 2 on page
98. Tagged ports have been added to simplify network implementation
and management.

One of the tagged ports is Port 8 on the top switch. This port has been
made a tagged member of the three VLANs. It is connected to an IEEE
802.1Q-compliant server, meaning the server can handle frames from
multiple VLANs. Now all three VLANs can access the server without
having to go through a router or other interconnection device.

It is important to note that even though the server is accepting frames
from and transmitting frames to more than one VLAN, data separation
and security remain.

Two other tagged ports are used to simplify network design in the
example. They are Port 16 on the top switch and Port 15 on the bottom
switch. These ports have been made tagged members of the Sales and
Engineering VLANs. They provide a connection between the different
parts of these two VLANs.

In the Port-based Example 2 on page 98, each VLAN had to have its
own data link between the switches to connect the different parts of the
VLANs. But with tagged ports, you can use one data link to carry data
traffic from several VLANs, while still maintaining data separation and
security. The tagged frames, when received by the switch, are delivered
only to those ports that belong to the VLAN from which the tagged
frame originated.

Sales VLAN (VID 2)

Engineering VLAN (VID 3)

Production VLAN (VID 4)

Untagged Ports Tagged Ports

AT-8024
Switch
(top)

1 to 5, 18
(PVID 2)

8, 16

9 to 11, 20
(PVID 3)

8, 16

21 to 24 (PVID 4) 8

AT-8024
Switch
(bottom)

1 to 5 (PVID 2)

19 to 24
(PVID 3)

none