VLANS

VLAN(VIRTUAL LOCAL AREA NETWORK)

What is Vlan?

Vlan is a virtually divided part of a physical switch. The division results in better security and traffic Management.

VLAN Features:

* Each VLAN is managed buy switch in itself

* In a network, total we can have 4096 VLAN & local support may vary.

* Two different Vlans will not commuinicate with each other.

* By default switch supports 6 vlans

  Vlan0 -> Voice traffic
  
   Vlan1 -> Data

   Vlan1002
   Vlan1003
   Vlan1004  ---------------->> Token Ring & FDDI
   Vlan1005

* By default all the switch ports are member of Vlan1

* A Vlan can have any number of nembers. A port can access only one Vlan at a time


Methods to create vlans:

Virtual LAN can be created by using two methods:

1>Manual: vlans are created within the switch and the members are switch ports.

2>Dynamic: vlans are created using Vmps(Virtual Lan membership protocol server)

Example: CISCO works 2000

This is software that maintain the virtual databases. Switches use the database to manage Vlan traffic.
Members are MAC addresses. It is more secure.

//To configure vlan:
switch# conft
switch(config)# vlan 74
switch(config-vlan)#name sales
switch(config-vlan)#exit

switch(config)# vlan 43
switch(config-vlan)# name operation
switch(config-vlan)# ^z

Note: Firing ^Z means that out of configuration mode in cisco switches



//To make interface  member of vlan43:

switch#conft
switch(config)#int fa0/15
switch(config-if)#switchport access vlan 43
switch(config-if)#exit


//To make multiple interfaces member to vlan74:

switch#conft
switch(config)# interface range fa0/1 - 5, fa0/8, fa0/12
switch(config)#switchport access vlan 74
switch(config)# ^z

Explanation:  Interface 15 is the member of vlan 43 & Interface 1,2,3.4,5,8,12 are the members of vlan 74

//To see vlan database:

switch# sh vlan brief