Netgear GS724TS-100NAS Manuale Utente

Packets leaving the switch are either tagged or untagged, depending on the setting for 

that port’s VLAN membership properties. A U for a given port means that packets leaving 
the switch from that port are untagged. Inversely, a T for a given port means that packets 
leaving the switch from that port are tagged with the VLAN ID that is associated with the 
port.

The example given in this section comprises numerous steps to illustrate a wide range of 
configurations to help provide an understanding of tagged VLANs.

VLAN Example Configuration

This example demonstrates several scenarios of VLAN use and describes how the switch 
handles tagged and untagged traffic.

In this example, you create two new VLANs, change the port membership for default 
VLAN

 

1, and assign port members to the two new VLANs:

In the Basic VLAN Configuration screen (see 

create 

the following VLANs:

A VLAN with VLAN ID 10.

A VLAN with VLAN ID 20.

specify the VLAN membership as follows:

For the default VLAN with VLAN ID 1, specify the following members: port 7 (U) and 

port 8 (U).

For the VLAN with VLAN ID 10, specify the following members: port 1 (U), port 2 (U), 

and port 3 (T).

For the VLAN with VLAN ID 20, specify the following members: port 4 (U), port 5 (T), 

and port 6 (U).

specify the PVID for ports e1 and e4 so that packets entering these ports are tagged with the 

port VLAN ID:

Port e1: PVID 10

Port e4: PVID 20

With the VLAN configuration that you set up, the following situations produce results as 

described:

If an untagged packet enters port 1, the switch tags it with VLAN ID 10. The packet 

has access to port 2 and port 3. The outgoing packet is stripped of its tag to leave port 

2 as an untagged packet. For port 3, the outgoing packet leaves as a tagged packet 

with VLAN ID 10.

If a tagged packet with VLAN ID 10 enters port 3, the packet has access to port 1 and 

port 2. If the packet leaves port 1 or port 2, it is stripped of its tag to leave the switch 

as an untagged packet.

If an untagged packet enters port 4, the switch tags it with VLAN ID 20. The packet 

has access to port 5 and port 6. The outgoing packet is stripped of its tag to become 

an untagged packet as it leaves port 6. For port 5, the outgoing packet leaves as a 

tagged packet with VLAN ID 20.