VLAN was introduced to mitigate broadcasts on switches, as all switch ports hear any broad cast.
VLAN (Virtual LAN) works as follow :
- each port on a switch can be assigned to one and only one VLAN ( all ports are assigned to VLAN 1 by default).
- when creating new VLAN and assign ports to it , these ports can only communicate with each other up to layer 2 ( datalink layer)
-hosts connected to a certain VLAN are configured with IP addresses belong to certain subnet mask, so layer 3 communication is not allowed between hosts connected to different VLANs.
- to allow connectivity between devices connected to different VLAN , layer 3 device is needed ( routers or layer 3 switches) to route traffic between VLANs ( different subnets).
using VLANs to segment your network can be useful to control brodcast traffic and implement security boundarise.However,allowing absolutely NO access between VLANs is never beneficial.To fix this,we need to implement inter-VLAN routing..And to make this happen there are two ways:
1-Attach a unique router port to each VLAN
2-Implement router on a stick
using create VLANs to reduce the network broadcasts and increasing your security.
you need first create vlans,assosaite ports to its vlan,if your network complex you need assoiate trunk ports between Switches to switches and between switches and routers.
finally used routing method to mack the traffic pass between the deiffrents VLAn you can used one from the following method:-
1-router on stock (used one router and sub-interface).
2-assoiate router for each vlan.
3-used L3 switch for inter-vlan rounting
There is no such thing as intervlan. There are Vlans and there is inter vlan routing.
VLAN create segments in a broadcast domain. there can be many reasons to segment the network but most obvious are to provide security and to limit the broadcast.
Intervlan routing are basincally used to enable communciation between different VLANS.
This is just a very brief answers for why. You can find alot of detailed literature on HOW and WHAT.
