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VLANs (Virtual Local Area Networks)
K KANISHK RAJ NETWORK ENGG.
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 Two S ubnets
Sw itch 1172.30.1.21255.255.255.0
VLAN 1
172.30.2.10255.255.255.0
VLAN 2
172.30.1.23255.255.255.0
VLAN 1
172.30.2.12255.255.255.0
VLAN 2
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)
VLANs10.1.0.0/8
172.2.0.0/16
192.3.0.0/24
Benefits of VLANs
• Increased security• Segmentation• Flexibility • Create broadcast domains• Control network traffic• Cost effective
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
VLAN Membership Modes
Courtesy of Rick Graziani [email protected]
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
Courtesy of Rick Graziani [email protected]
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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.
Courtesy of Rick Graziani [email protected]
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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
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.
Configuration modes: Global configuration mode
– SwitchX#configure terminal– SwitchX(config)#
Configuring the Switch
Adding a VLAN
SwitchX# configure terminalSwitchX(config)# vlan 2SwitchX(config-vlan)# name switchlab99
Courtesy of Rick Graziani [email protected]
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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 1Switch(config-if)#ip address 10.1.0.5. 255.255.0.0Switch(config-if)#no shutdownSwitch(config-if)#exitSwitch(config)#ip default-gateway 10.1.0.1
Courtesy of Rick Graziani [email protected]
15
Verifying VLANs – show vlan brief
vlan 3vlan 2vlan 1 default
THANK YOU
I hope ,It is useful for Students
