A VLAN (Virtual Local Area Network) logically segments devices within a network, allowing users in different physical locations to communicate as if they are on the same LAN. VLANs can be configured as static or dynamic, with static VLANs assigned based on port connection and dynamic VLANs based on device MAC addresses. Using VLANs improves performance, administration, and security while enabling the formation of virtual workgroups.

1. VLAN
-VIRTUAL LAN
NITHIN KALLEPALLY
COMPUTER
NETWORKS

2. LAN
 A Local Area Network (LAN) was originally defined
as a network of computers located within the same
area
 Local Area Networks are defined as a single
broadcast domain. This means that if a user
broadcasts information on his/her LAN, the
broadcast will be received by every other user on the
LAN.
 Broadcasts are prevented from leaving a LAN by
using a router. The disadvantage of this method is
routers usually take more time to process incoming
data compared to a bridge or a switch

3. VLAN
A VLAN is a logical group of network devices
that appears to be on the same LAN
Configured as if they are attached to the
same physical connection even if they are
located on a number of different LAN
segments.
Logically segment LAN into different
broadcast domains.

4. VLAN
 VLANs can logically segment users into different
subnets (broadcast domains)
 Broadcast frames are only switched on the same
VLAN ID.
 This is a logical segmentation and not a physical one,
workstations do not have to be physically located
together. Users on different floors of the same
building, or even in different buildings can now
belong to the same LAN.

5. LAN VS VLAN
 By using switches, we can
assign computer on
different floors to VLAN1,
VLAN2, and VLAN3
 Now, logically, a
department is spread
across 3 floors even
though they are
physically located on
different floors

7. VLAN Configurations

8. STATIC VLANS
 Static membership VLANs are called port-based and port-
centric membershipVLANs.
 This is the most common method of assigning ports to
VLANs.
 As a device enters the network, it automatically assumes the
VLAN membership of the port to which it is attached.
 There is a default VLAN, on Cisco switches that isVLAN 1.
Default
VLAN 1
Default
VLAN 1
Configured
Vlan 10

9. DYNAMIC VLANS
Dynamic membership VLANs are created through network
management software
Dynamic VLANs allow for membership based on the MAC
address of the device connected to the switch port.
As a device enters the network, it queries a database within
the switch for aVLAN membership

10. CONFIGURING PORTS
 Access ports are used when:
 Only a single device is connected to the port
 Multiple devices (hub) are connected to the port, all
belonging to the sameVLAN
 Another switch is connected to this interface, but this
link is only carrying a singleVLAN (non- trunk link).
 Trunk ports are used when:
 Another switch is connected to this interface, and this
link is carrying multipleVLANs(trunk link).

11. • Switch(config-if)switchport mode
[access|trunk]
• An access port means that the port (interface)
can only belong to a single VLAN.

12. ADVANTAGES
• Performance
• Formation ofVirtualWorkgroups
• SimplifiedAdministration
• Reduced Cost
• Security

13. THANK
YOU…