VLAN

A vlan typically is a single broadcast domain. The vlan gets defined on the switch and at the switchport level specific ports are placed in that vlan.

eg.

conf t vlan 2 name my_new_vlan exit

int range gi0/1 - 12 switchport switchport access vlan 2 switchport mode access exit

Switchports 1 through 12 are now in vlan 2. Unless the switch can switch at layer 3 (aka route) it cannot pass packets from one vlan to another.

BernieM

Isnt it that different VLANs are in different broadcast domains and the switched make a single broadcast domain? thank you Shaun

Diferent vlans are different broadcast domains. Having multiple vlans on a single switch doesn't make them become a single broadcast domain .. that would defeat the purpose.

BernieM

Maybe wrong here, but don't VLANs create different collision domains - routers would create different broadcast domains? john

Each port in a LAN switch is usually a different collision domain. VLANs are different broadcast domains that share the same switches (So, it=B4s like having fully separated LANs). Because VLANs are different bradcast domains, you need a Router in order to forward frames between VLANs.

Lokke