| ext">As a CCNA students you must be familiar | | | | to see how to configure the device. |
| with and comfortable with the concepts of Vlans | | | | In this exercise the task is to create 3 additional |
| Before you get into what they are is you need to | | | | vlans and place 8 ports into each vlan, the result |
| understand what a Local area network is. | | | | ought to be that the switch has 3 new broadcast |
| The definition of a Local Area Network (LAN) is a | | | | domain. |
| collection of network devices located on a shared | | | | Switch# |
| broadcast domain. This broadcast domain may | | | | Switch#configure terminal |
| comprise one physical backbone like a Co-axial | | | | Switch(config)#vlan 2 |
| cable with drop cables running back to the hosts | | | | Switch(config-vlan)#exit |
| on the LAN. | | | | Switch(config)#vlan 3 |
| The number of devices on the shared broadcast | | | | Switch(config-vlan)#exit |
| domain will have an impact on the performance of | | | | Switch(config)#vlan 4 |
| your network. Hosts on the network are | | | | Switch(config-vlan)#exit |
| continually sending out broadcasts on discover | | | | In the example above the commands used |
| other hosts on the local network segment | | | | created and additional 3 vlans on our switch |
| Broadcasts are a necessary evil on your | | | | Switch(config)#interface range fastethernet 0/1 - |
| networks, without them your hosts would and | | | | 8 |
| could not discover the layer 2 addresses of other | | | | Switch(config-if-range)#switchport mode access |
| machines on the local LAN. | | | | Switch(config-if-range)#switchport access vlan 2 |
| This is where you start to consider implementing | | | | Switch(config-if-range)#exit |
| vlans on your network. With vlans operating on | | | | Switch(config)#interface range fastethernet 0/9 - |
| your networks you can control the scope or | | | | 16 |
| range of the broadcast and contain it and prevent | | | | Switch(config-if-range)#switchport mode access |
| it from affecting all host across your lans. | | | | Switch(config-if-range)#switchport access vlan 3 |
| Not only can you prevent broadcasts from | | | | Switch(config-if-range)#exit |
| unnecessarily interrupting hosts you also use vlans | | | | Switch(config)#interface range fastethernet 0/17 |
| to group hosts with similar functions into a | | | | - 24 |
| common vlan for the purposes of security. Once | | | | Switch(config-if-range)#switchport mode access |
| a Host is on a vlan it is protected from seeing or | | | | Switch(config-if-range)#switchport access vlan 4 |
| being seen by devices on other vlans, even of | | | | In the commands above: |
| the host on other vlan is on the next port along. | | | | The ports numbered from 1 through 8 were |
| Using vlans allows us to logical partition your | | | | assigned to v2 |
| switches. | | | | The ports numbered from 9 through 16 were |
| Using vlans to logically partition your switches you | | | | assigned to v3 |
| do away with the need to purchase any further | | | | The ports numbered from 17 through 24 were |
| equipment to segment your network. | | | | assigned to v4 |
| Lets look at partitioning the switch into logical | | | | Switch(config-if-range)#end |
| segments. When the switch first arrives out of | | | | Switch#copy run start |
| the box or is defaulted back to factory defaults | | | | Finally we save our configuration. |
| all of the ports are in one common vlan known as | | | | In all our fictional switch now has 3 new broadcast |
| VLAN 1. This entity is also referred to as the | | | | domains, by populating all of our switchports with |
| NATIVE VLAN. | | | | hosts it would have the effect of securing the |
| When you connect your network hosts into the | | | | visibility of host on one broadcast domain from |
| ports all subsequent traffic which they generate | | | | seeing hosts on one of the other broadcast |
| will be placed into the vlan of that connected port, | | | | domains from a security stand point this is ideal |
| in the default case this would be V1, all devices | | | | and from a performance point of view it achieves |
| which are connected to this vlan are going to see | | | | exactly what we need |
| all other hosts broadcast traffic, so here we see | | | | Commsupport Networks provides you with low |
| that by merely placing the devices into a vlan | | | | cost quality Cisco CCNA training in the uk in a |
| does not mean the broadcasts will cease. | | | | classroom or live on-line web based environment. |
| We are going to use and example 24 port switch | | | | |