As a CCNA students you need to be familiar with and comfortable with the ideas of Vlans. Just before you get into what they are is you require to recognize what a Regional location network is.
The definition of a Regional Location Network (LAN) is a collection of network devices positioned on a shared broadcast domain. This broadcast domain might comprise a single physical backbone like a Co-axial cable with drop cables operating back to the hosts on the LAN.
The number of devices on the shared broadcast domain will have an effect on the efficiency of your network. Hosts on the network are continually sending out broadcasts on learn other hosts on the nearby network segment. Broadcasts are a essential evil on your networks, without them your hosts would and could not find out the layer 2 addresses of other machines on the local LAN.
This is exactly where you commence to think about implementing vlans on your network. With vlans operating on your networks you can handle the scope or variety of the broadcast and contain it and prevent it from affecting all host across your lans.
Not only can you avoid broadcasts from unnecessarily interrupting hosts you also use vlans to group hosts with equivalent functions into a common vlan for the purposes of security. Once a Host is on a vlan it is protected from seeing or getting seen by devices on other vlans, even of the host on other vlan is on the subsequent port along. Utilizing vlans makes it possible for us to logical partition your switches.
Making use of vlans to logically partition your switches you do away with the need to purchase any further gear to segment your network.
Lets appear at partitioning the switch into logical segments. When the switch very first arrives out of the box or is defaulted back to factory defaults all of the ports are in one common vlan recognized as VLAN 1. This entity is also referred to as the NATIVE VLAN.
When you connect your network hosts into the ports all subsequent visitors which they produce will be placed into the vlan of that connected port, in the default case this would be V1, all devices which are connected to this vlan are going to see all other hosts broadcast traffic, so here we see that by merely placing the devices into a vlan does not mean the broadcasts will cease.
We are going to use and example 24 port switch to see how to configure the device.
In this exercise the job is to create three additional vlans and place eight ports into each vlan, the result ought to be that the switch has 3 new broadcast domain.
Switch#
Switch#configure terminal
Switch(config)#vlan two
Switch(config-vlan)#exit
Switch(config)#vlan 3
Switch(config-vlan)#exit
Switch(config)#vlan 4
Switch(config-vlan)#exit
In the example above the commands utilised developed and extra three vlans on our switch
Switch(config)#interface variety fastethernet /1 - eight
Switch(config-if-range)#switchport mode access
Switch(config-if-variety)#switchport access vlan 2
Switch(config-if-variety)#exit
Switch(config)#interface variety fastethernet /9 - 16
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan three
Switch(config-if-variety)#exit
Switch(config)#interface variety fastethernet /17 - 24
Switch(config-if-range)#switchport mode access
Switch(config-if-variety)#switchport access vlan 4
In the commands above:
The ports numbered from 1 by way of 8 have been assigned to v2
The ports numbered from 9 by means of 16 were assigned to v3
The ports numbered from 17 through 24 have been assigned to v4
Switch(config-if-variety)#end
Switch#copy run commence
Lastly we save our configuration.
In all our fictional switch now has 3 new broadcast domains, by populating all of our switchports with hosts it would have the impact of securing the visibility of host on a single broadcast domain from seeing hosts on one of the other broadcast domains from a security stand point this is best and from a performance point of view it achieves exactly what we need to have
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Joe is a senior lecturer at Commsupport networks in the United Kingdom. Joe teaches Cisco CCNA, CCNP, CCVP courses when he is not out on the road fixing and building networks, if you want to uncover out more about what we do at Commsupport. Please pay a visit to us at CCNA Course
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