64 CHAPTER 8: SETTING UP VIRTUAL LANS
To carry multiple VLANs across a single physical (backbone) link, each 
packet must be tagged with a VLAN identifier so that the Switches can 
identify which packets belong in which VLANs. To communicate between 
VLANs a router must be used.
VLAN 
Configuration 
Examples
This section contains examples of VLAN configurations. It describes how 
to set up your Switch to support simple untagged and tagged 
connections.
Using Untagged
Connections
The simplest VLAN operates in a small network using a single switch. In 
this network there is no requirement to pass traffic for multiple VLANs 
across a link. All traffic is handled by the single Switch and therefore 
untagged connections can be used.
The example shown in Figure 17
 illustrates a single Switch connected to 
endstations and servers using untagged connections. Ports 1, 2 and 3 of 
the Switch belong to VLAN 1, ports 10, 11 and 12 belong to VLAN 2. 
VLANs 1 and 2 are completely separate and cannot communicate with 
each other. This provides additional security for your network.
Figure 17   VLAN configuration example: Using untagged connections