Netgear GSM7224v2 - 24-Port Layer 2 Managed Gigabit Switch User Manual

traffic is contained largely within the VLAN, reducing extraneous traffic and improving the 
efficiency of the whole network.

They are easy to manage. The addition of nodes, as well as moves and other changes, 

can be dealt with quickly and conveniently from a management interface rather than from 
the wiring closet.

They provide increased performance. VLANs free up bandwidth by limiting node-to-node 
and broadcast traffic throughout the network.

They ensure enhanced network security. VLANs create virtual boundaries that can be 

crossed only through a router. So standard, router-based security measures can be used 
to restrict access to each VLAN.

Packets received by the switch are treated in the following way:

When an untagged packet enters a port, it is automatically tagged with the port’s default 

VLAN ID tag number. Each port has a default VLAN ID setting that is user configurable 
(the default setting is 1). The default VLAN ID setting for each port can be changed in the 
Port PVID Configuration screen. See 

When a tagged packet enters a port, the tag for that packet is unaffected by the default 

VLAN ID setting. The packet proceeds to the VLAN specified by its VLAN ID tag number.

If the port through which the packet entered does not have membership with the VLAN 

specified by the VLAN ID tag, the packet is dropped.

If the port is a member of the VLAN specified by the packet’s VLAN ID, the packet can be 

sent to other ports with the same VLAN ID.

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: