Virtual LAN-Part 1

In computer networking, a single layer-2 network may be partitioned to create multiple distinct broadcast domains, which are mutually isolated so that packets can only pass between them via one or more routers; such a domain is referred to as a virtual local area network, virtual LAN or VLAN.

This is usually achieved on switch or router devices. Simpler devices only support partitioning on a port level (if at all), so sharing VLANs across devices requires running dedicated cabling for each VLAN. More sophisticated devices can mark packets through tagging, so that a single interconnect (trunk) may be used to transport data for various VLANs.

Grouping hosts with a common set of requirements regardless of their physical location by VLAN can greatly simplify network design. A VLAN has the same attributes as a physical local area network (LAN), but it allows for end stations to be grouped together more easily even if they are not on the same network switch. VLAN membership can be configured through software instead of physically relocating devices or connections. Most enterprise-level networks today use the concept of virtual LANs. Without VLANs, a switch considers all interfaces on the switch to be in the same broadcast domain.

To physically replicate the functions of a VLAN would require a separate, parallel collection of network cables and equipment separate from the primary network. However, unlike physically separate networks, VLANs share bandwidth, so VLAN trunks may require aggregated links and/or quality of service prioritization. source : http://en.wikipedia.org/wiki/Virtual_LAN

Example:

1. Go to Switch Device (CLI)to configure or Create VLAN Name:

VLAN 10 : Marketing Departement : 192.168.0.0/26 (range port - f0/1-5)
VLAN 20 : Accounting Departement : 192.168.0.64/26 (range port - f0/6-10)
VLAN 30 : HRD Departement:192.168.0.128/26 (range port - f0/11-18)
VLAN 40 : Manager : 192.168.0.192/26 (range port - f0/19-22)

Switch>enable

Switch#configure terminal

Switch(config)#hostname 1stfloor

1stfloor(config)#vlan 10

1stfloor(config-vlan)#name marketing

1stfloor(config-vlan)#vlan 20

1stfloor(config-vlan)#name accounting

1stfloor(config-vlan)#vlan 30

1stfloor(config-vlan)#name hrd

1stfloor(config-vlan)#vlan 40

1stfloor(config-vlan)#name manager

1stfloor(config-vlan)#end

1stfloor#

2. assign port with VLAN

1stfloor#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

1stfloor(config)#interface range f0/1-5

1stfloor(config-if-range)#switchport access vlan 10

1stfloor(config-if-range)#interface range f0/6-10

1stfloor(config-if-range)#switchport access vlan 20

1stfloor(config-if-range)#interface range f0/11-18

1stfloor(config-if-range)#switchport access vlan 30

1stfloor(config-if-range)#interface range f0/19-22

1stfloor(config-if-range)#switchport access vlan 40

1stfloor(config-if-range)#end

3.Show data configuration that you created:

1stfloor#show vlan brief

4. Don't forget to assign IP address in each of PC.

VLAN 10:

VLAN 20:

VLAN 30:

VLAN 40:

You success to prepare VLAN Network. Continue to Inter-VLAN Configuration >>