Introduction of VLAN

          Vlan (Virtual Local Area Network) Foundation:-   Switch Vlan

Ø  Trunk Port :- That Carry All Vlan Traffic Between Your Switches

ü  Logically Groups Users

ü  Segments Broadcast Domain

ü  Subnet Correlation

ü  Access Control

ü  Quality Of Service

v  The Normal Switches World:-

Ø  1 Collision Domain Per Port

Ø  Broadcast Sent To All Ports

Ø  One Subnet Per Lan

Ø  Very Limited Access Control

 

The Flexibility Of Vlans:-

Ø   Segmentation Of Users Without Routers

Ø  No Longer Limited To Physical Location

Ø  Tighter Control Of Broadcast

 Understanding Trunks and VTP              

•  
    
  • What is Trunking
  Ø Trunking(also known as Tagging) passes multi-Vlan information b/w switches
  Ø Places Vlan information into each frame
  Ø Layer 2 feature
  Ø Trunking is a Cisco term.
  
  
  •    Trunking Language : 802.1Q
  Ø Switches pass the information b/w each other using official languages 802.1Q that is industry standard
                                          
  

•    Native Vlan:- is designed for packet that received on the trunk that are not tag

• Double Edge word: VTP 
• VLAN Trunking Protocol (VTP):-It Replicate the Vlans into Multiple Switches through Trunk Ports

The VTP Modes:-

Ø  Server(Default)

ü  Power to change vlan information

ü  Sends and receive vtp updates

ü  Saves vlan configuration

Ø  Client

ü  Cannot change vlan information

ü  Sends and receive vtp updates

ü  Does not save vlan configuration

Ø  Transparent

ü  Power to change vlan information

ü  Forward (pass through) vtp updates

ü  Does not listen to vtp advertisements

ü  Saves Vlan configuration

  Ø  Off (configurable only in CatOS switches):- in the VTP off mode, switches behave the same as in VTP transparent mode with the exception that VTP advertisements are not forwarded.

Vlan Pruning

Ø  Keeps unnecessary broadcast traffic from crossing trunk link.

Ø  Only work on VTP Server