What is a Virtual Local Area Network (VLAN)

What is a Virtual Local Area Network (VLAN) networkingguruji1.com/2020/01/what-is-virtual-local-area-network-vlan.html

My Dear Friend in today’s article, I will tell you “What is a Virtual Local Area Network (VLAN)” If you any problem after reading this article, you can see the video below. Please don't forget to Like, Share, Comment & Subscribe to our Networking Guruji Channel for more video.

Previous post: - What is Cisco Discovery Protocol (CDP)…. click here And Disabling Dynamic Trunking Protocol (DTP)…. click here

VLAN (Virtual Local Area Network) Definition VLAN is used to break-up-broadcast domain in the L2 network. VLAN can be configured in three different ways.

--- Global configuration mode --- VLAN database mode --- AT the time of assignment The above configuration has shown in the global configuration mode. Now we will see how we can configure VLAN ID in VLAN database mode and at the time of the assignment.

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By default, all switch port on a switch is assigned to default VLAN ID 1, this is the reason we say one switch is in one broadcast domain.

There are different types of VLAN exist by their name L2 technology, now we will see what are those VLAN’s name.

VLAN ID 1 is called default VLAN. VLAN ID 1 to 1005 is called normal range of VLAN. VLAN ID 1006 to 4094 is called external VLAN. VLAN ID 1002 to 1005 are reserved for FDDI and Token Ring Technology.

Virtual Local Area Networks (VLAN) Configure VLAN ID 10,20,30, on SW-1, SW-2 and SW-3, SW-4. Also, configure the following name of respective VLAN ID (the name is case sensitive).

VLAN ID 10 name – Sales VLAN ID 20 name – Admin VLAN ID 30 name – IT Assign VLAN ID 10 on SW-3 port fa0/3 and SW-4 port fa0/3. Assign VLAN ID 20 on SW-3 port 2/10

fa0/4 and SW-4 port fa0/4.

Configure IP as bellow on PCs. PC-1 --- 172.16.10.1/24 PC-2 --- 172.16.20.1/24 PC-3 --- 172.16.10.2/24 PC-4 --- 172.16.20.2/24 Virtual LAN (VLAN) Configuration SW-1 SW-1(config)#vlan 10 SW-1(config-vlan)#name sales SW-1(config)#vlan 20 SW-1(config-vlan)#name admin SW-1(config)#vlan 30 SW-1(config-vlan)#name it SW-2 SW-2(config)#vlan 10 SW-2(config-vlan)#name sales SW-2(config)#vlan 20 SW-2(config-vlan)#name admin SW-2(config)#vlan 30 SW-2(config-vlan)#name it SW-3 SW-3(config)#vlan 10 SW-3(config-vlan)#name sales SW-3(config)#vlan 20 SW-3(config-vlan)#name admin SW-3(config)#vlan 30 SW-3(config-vlan)#name it SW-3(config)#interface fastethernet 0/3 SW-3(config-if)#switchport access port vlan 10 SW-3(config-if)#interface fastethernet 0/4 SW-3(config-if)#switchport access port vlan vlan 20 3/10

SW-4 SW-4(config)#vlan 10 SW-4(config-vlan)#name sales SW-4(config)#vlan 20 SW-4(config-vlan)#name admin SW-4(config)#vlan 30 SW-4(config-vlan)#name it SW-4(config)#interface fastethernet 0/3 SW-4(config-if)#switchport access vlan 10 SW-4(config-if)#interface fastethernet 0/4 SW-4(config-if)#switchport access vlan 20 Let’s see verification of VLAN exist by their name L2 technology, now we will see what are those VLAN’s name.

SW-1#Show VLAN VLAN

Name

Status

1

10 20 30 1002 1003 1004 1005

Default

Sales Admin IT

Ports

active

fa0/3, fa0/4, fa0/5, fa0/6 fa0/7, fa0/8, fa0/9, fa0/10 fa0/11, fa0/12, fa013/, fa0/14 fa0/15, fa0/16, fa0/17, fa0/18 fa0/19, fa0/20, fa0/21, fa0/22 fa0/23, fa0/24, gig1/1, gig1/2

active active active

fddi-default token-ring-default fddinet-default trnet-default

act/unsup act/unsup act/unsup act/unsup

SW-2#Show VLAN VLAN

Name

Status

Ports 4/10

1

Default

10 20 30 1002 1003 1004 1005

active

Sales Admin IT

fa0/3, fa0/4, fa0/5, fa0/6 fa0/7, fa0/8, fa0/9, fa0/10 fa0/11, fa0/12, fa013/, fa0/14 fa0/15, fa0/16, fa0/17, fa0/18 fa0/19, fa0/20, fa0/21, fa0/22 fa0/23, fa0/24, gig1/1, gig1/2 active active active

fddi-default token-ring-default fddinet-default trnet-default

act/unsup act/unsup act/unsup act/unsup

SW-3#Show VLAN

VLAN

Name

1

Default

10 20 30 1002 1003 1004 1005

Status

Ports

active

Sales Admin IT

fa0/5, fa0/6, fa0/7, fa0/8, fa0/9, fa0/10, fa0/11, fa0/12, fa013/, fa0/14 fa0/15, fa0/16, fa0/17, fa0/18, fa0/19, fa0/20, fa0/21, fa0/22, fa0/23, fa0/24, gig1/1, gig1/2

active active active

fddi-default token-ring-default fddinet-default trnet-default

fa0/3 fa0/4

act/unsup act/unsup act/unsup act/unsup

SW-4#Show VLAN VLAN

Name

Status

Ports 5/10

1

10 20 30 1002 1003 1004 1005

Default

active

Sales Admin IT fddi-default token-ring-default fddinet-default trnet-default

active active active

fa0/5, fa0/6, fa0/7, fa0/8, fa0/9, fa0/10, fa0/11, fa0/12, fa013/, fa0/14 fa0/15, fa0/16, fa0/17, fa0/18, fa0/19, fa0/20, fa0/21, fa0/22, fa0/23, fa0/24, gig1/1, gig1/2 fa0/3 fa0/4

act/unsup act/unsup act/unsup act/unsup

“Virtual Local Area Networks� on the above output we can see on all four switches VLAN ID 10, 20 & 30 are created and status is active. Also, we can see little different in SW-3 and SW-4 output while we compare between SW-1 and SW-2 output. The different is port fa0/3 is assigned to VLAN ID 10 and port fa0/4 is assigned to VLAN ID 20 on SW-3 and SW-4 as PC's are connected.

We can also see access VLAN ID assignment on the following command output.

SW-3#show interface status 6/10

Port Name status Fa0/1 connected Fa0/2 connected Fa0/3 connected Fa0/4 connected Fa0/5 notconnected Fa0/6 notconnected Fa0/7 notconnected

VLAN trunk trunk 10 20 1 1 1

Duplex Speed a-full a-100 a-full a-100 a-full a-100 a-full a-100 auto auto auto auto auto auto

Type 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX

VLAN trunk trunk 10 20 1 1 1

Duplex Speed a-full a-100 a-full a-100 a-full a-100 a-full a-100 auto auto auto auto auto auto

Type 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX 10/1000baseTX

SW-4#show interface status Port Name status Fa0/1 connected Fa0/2 connected Fa0/3 connected Fa0/4 connected Fa0/5 notconnected Fa0/6 notconnected Fa0/7 notconnected

“Virtual LAN” Note: - Also we can find on the above output port fa0/1 and fa0/2 not showing on all the four switches. The reason is port fa0/1 and fa0/2 both are configured as a trunk port on all switches and trunk ports are not showing on show VLAN or show VLAN brief output.

802.1q Trunking Configuration Cisco Catalyst Switches… Click here

And Configuring ISL Trunking Cisco Catalyst Switch…. Click here

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Now test pin from pc-1 to pc-3 and test ping from pc-2 to pc-4 PC-1 PC>ping 172.16.10.2 Pinging 172.16.10.2 with 32 bytes of data Reply from 172.16.10.2: bytes=32 time-2ms TTL=128 Reply from 172.16.10.2: bytes=32 time-0ms TTL=128 Reply from 172.16.10.2: bytes=32 time-0ms TTL=128 Reply from 172.16.10.2: bytes=32 time-0ms TTL=128 Ping statistics for 172.16.10.2: Packet: sent = 4, Received =4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Maximum = 0ms, Maximum = 2ms, Average = 0ms PC-2 PC>ping 172.16.20.2 8/10

Pinging 172.16.20.2 with 32 bytes of data Reply from 172.16.20.2: bytes=32 time-11ms TTL=128 Reply from 172.16.20.2: bytes=32 time-0ms TTL=128 Reply from 172.16.20.2: bytes=32 time-0ms TTL=128 Reply from 172.16.20.2: bytes=32 time-0ms TTL=128 Ping statistics for 172.16.20.2: Packet: sent = 4, Received =4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Maximum = 0ms, Maximum = 11ms, Average = 0ms Example of VLAN Database mode: cisco recommends not to use this mode to configure VLAN, use Global config mode as you see a bellow warning message. VLAN database command should run from enable mode. Type exit to come out from this mode.

SW-1#vlan database %warning: it is recommended to configure VLAN config mode, VLAN database mode is being deprecated. Please consult user documentation for configuring VTP/VLAN in config mode.

Extended VLANs --- Extended VLANs range is 1006 – 4094 --- We can configure extended VLAN in VTP Transparent mode

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Virtual LAN (VLAN) Example of configuring VLAN ID at the time of the VLAN assignment on a port.

SW-1(config)#interface fastethernet 0/10 SW-1(config-if)#switchport access VLAN 100 % Access VLAN does not exist. Creating VLAN 100 NOTE: - cisco recommended way is Global config mode to configure VLAN

This is a full article “What is a Virtual Local Area Network (VLAN)” Thank you so much.

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