Allied Telesis AT-S60 - Manual (Page 256)

AT-S60 Management Software User’s Guide
Section II: Local and Telnet Management 255
This example is nearly identical to the port-based VLAN Example 2 earlier
in this chapter. Tagged ports have been added to simplify network
implementation and management.
The port assignments for the VLANs are as follows:
One of the changes is the addition of an IEEE 802.1Q-compliant server.
This server can handle frames from multiple VLANs. It is connected to
Port 8 on the AT-8411 TX line card in Slot 1 of the AT-8400 Series switch.
Port 8 has been made a tagged port of both the Sales and Production
VLANs. This allows the workstations of the VLANs to access the server
without having to use the router.
It is important to note that even though the server accepts frames from
and transmits frames to more than one VLAN, data separation and
security remain. The frames from the server to the switch contain VID
information that tell the switch which VLAN the packet belongs to. This
prevents packets from crossing VLAN boundaries.
Another use of tagged ports in the example eliminates the need for
separate, dedicated links to connect together VLANs that span multiple
switches. Back in the port-based Example 2 on page 249, the Sales and
Production VLANs each had separate links to connect together their
different parts.
But in this example, tagged ports allow one data link to carry packets
from different VLANs, but network security is maintained. Tagged
frames, when received by the switch, are delivered only to those ports
that belong to the VLAN from which the frames originated.
This shared data link is provided by Port 4 on the AT-8411 TX line card in
Slot 4 of the AT-8400 Series switch and by Port 17 on the AT-8024 switch.
Both ports have been made tagged ports of both the Sales VLAN and the
Production VLAN.
Each VLAN still has a dedicated connection to the router for access by
the Sales VLAN to the legacy server, and also so the two VLANs can
access the WAN.
Sales VLAN (VID 2) Production VLAN (VID 3)
Untagged Ports Tagged Ports Untagged Ports Tagged Ports
AT-8400 Switch Slot 1
Ports: 1 - 4
Slot 2
Ports: 1 - 2, 5
Slot 1
Port: 8
Slot 4
Port 4
Slot 4
Port: 1
Slot 5
Ports: 1 - 4
Slot 1
Port: 8
Slot 4
Port 4
AT-8024 Switch 1 - 4, 6 17 18 - 21 17