segregate traffic by type so that the time-sensitive traffic, like voice traffic, has
priority over other traffic, such as data. Administrators also use VLANs to
protect network resources. Traffic sent by authenticated clients might be
assigned to one VLAN, while traffic sent from unauthenticated clients might
be assigned to a different VLAN that allows limited network access.
When one host in a VLAN sends a broadcast, the switch forwards traffic only
to other members of that VLAN. For traffic to go from a host in one VLAN to
a host in a different VLAN, the traffic must be forwarded by a layer 3 device,
such as a router. VLANs work across multiple switches and switch stacks, so
there is no requirement for the hosts to be located near each other to
participate in the same VLAN.
PowerConnect M6220, M6348, M8024, and M8024-k switches support
VLAN routing. When you configure VLAN routing, the switch acts as a layer 3
device and can forward traffic between VLANs. For more information, see <VLAN
Each VLAN has a unique number, called the VLAN ID. The PowerConnect
M6220, M6348, M8024, and M8024-k switches support a configurable VLAN
ID range of 2–4093. A VLAN with VLAN ID 1 is configured on the switch by
default. You can associate a name with the VLAN ID. In a tagged frame, the
VLAN is identified by the VLAN ID in the tag. In an untagged frame, the
VLAN identifier is the Port VLAN ID (PVID) specified for the port that
received the frame. For information about tagged and untagged frames, see
"VLAN Tagging" on page 579.
The PowerConnect M6220, M6348, M8024, and M8024-k switches support
adding individual ports and Link Aggregation Groups (LAGs) as VLAN
Figure 21-1 shows an example of a network with three VLANs that are
department-based. The file server and end stations for the department are all
members of the same VLAN.