A
virtual local area network (VLAN) is a logical grouping of
network users and resources connected to administratively defined ports on
a layer 2 switch. By creating VLANs, you are able to create smaller broadcast
domains within a switch by assigning different ports in the switch to differ-
ent subnetworks. A VLAN is treated as its own subnet or broadcast domain.
This means that when frames are broadcast, they are switched between ports
only within the same VLAN.
Using virtual LANs, you're no longer confined to creating workgroups by
physical locations. VLANs can be organized by location, function, depart-
ment, or even the application or protocol used, regardless of where the
resources or users are located.
In this chapter, you'll learn about the following:
What a VLAN is.
How to configure VLANs on both set-based and IOS-based switches.
VLAN trunking and VLAN Trunk Protocol (VTP) configurations.
Trunking allows you to pass information about more than one
VLAN on the same link.
VTP is used to send VLAN configuration information between
switches.
Frame tagging and identification methods.
Identification methods both encapsulate a frame and insert a new
field in a frame to identify it as it traverses a switched internet-
work fabric.
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