The document provides an overview of Virtual Local Area Networks (VLANs), explaining their definition, benefits, and operations, including static and dynamic memberships. It highlights VLANs' roles in enhancing security, flexibility, segmentation, and cost-effectiveness within network management. Additionally, the document discusses VLAN trunking and configurations using Cisco switches.

1. VLANs (Virtual Local Area Networks)
K KANISHK RAJ
NETWORK ENGG.

2. What is the VLAN?
A VLAN stands for Virtual
Local Area Network.
VLAN is an independent
LAN Network.
VLAN is the Logical
division of Switched
network.
VLAN=Broadcast=Subnet
Two VLANs
Ÿ Two Subnets
Switch 1172.30.1.21
255.255.255.0
VLAN 1
172.30.2.10
255.255.255.0
VLAN 2
172.30.1.23
255.255.255.0
VLAN 1
172.30.2.12
255.255.255.0
VLAN 2

3. Why VLAN is effective?
• In LAN ,each group is on a different IP network and
on a different switch.
• VLAN provide segmention over single switch.
• VLAN use different IP addresses on a single switch.
Traditional
LAN
192.1.0.3/24
172.1.0.2/16
10.1.0.1/8
One link per VLAN or a single VLAN
Trunk (later)
VLANs
10.1.0.0/8
172.2.0.0/16
192.3.0.0/24

4. Benefits of VLANs
• Increased security
• Segmentation
• Flexibility
• Create broadcast domains
• Control network traffic
• Cost effective

5. How VLANs Work?
• VLANs are identified by a number
– Valid ranges 1-4094
• On a VLAN-capable switch, you assign ports
with the appropriate VLAN number
• The switch then only allows data to be sent
between ports with the same VLAN
5

6. VLAN Membership Modes

7. Courtesy of Rick Graziani
graziani@cabrillo.edu
7
VLAN operation

8. Courtesy of Rick Graziani
graziani@cabrillo.edu
8
Static VLANS
• Static membership VLANs are called port-based and port-centric
membership VLANs.
• 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 is VLAN 1.
VLAN 10
Configured
Default
VLAN 1
Default
VLAN 1

9. Courtesy of Rick Graziani
graziani@cabrillo.edu
9
Dynamic VLAN
• Dynamic membership VLANs are created through network
management software. (Not as common as static VLANs)
• 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 a VLAN membership.

10. Courtesy of Rick Graziani
graziani@cabrillo.edu
10
VLAN Trunking/Tagging
• VLAN Tagging is used when a single link needs
to carry traffic for more than one VLAN.
No VLAN Tagging
VLAN Tagging

11. VLAN Creation Guidelines
– The maximum number of VLANs is switch-
dependent.
– Most Cisco Catalyst desktop switches support 128
separate spanning-tree instances, one per VLAN.
– VLAN 1 is the factory default Ethernet VLAN.
– First open the switch interface command mode.

12. Configuration modes:
 Global configuration mode
– SwitchX#configure terminal
– SwitchX(config)#
Configuring the Switch

13. Adding a VLAN
SwitchX# configure terminal
SwitchX(config)# vlan 2
SwitchX(config-vlan)# name switchlab99

14. Courtesy of Rick Graziani
graziani@cabrillo.edu
14
Accessing/Managing the Switch
The IP Address, Subnet Mask, and Default Gateway on a switch is for the same purposes as when you
configure it for a host.
IP Address and Subnet Mask
• By default, VLAN 1 is the “management VLAN”.
• This is where you assign the IP Address and Subnet Mask to the switch.
• This address is for management purposes only and does not affect the Layer 2 switching
operations of the switch.
Switch(config)#interface vlan 1
Switch(config-if)#ip address 10.1.0.5. 255.255.0.0
Switch(config-if)#no shutdown
Switch(config-if)#exit
Switch(config)#ip default-gateway 10.1.0.1

15. Courtesy of Rick Graziani
graziani@cabrillo.edu
15
Verifying VLANs – show vlan brief
vlan 3vlan 2vlan 1
default

16. THANK YOU
I hope ,It is useful for Students