VLAN and DTP

VLAN

• Virtual LAN
• Physical Switch is Splitted into several logical Switch.
• It Breaks the Broadcast domain.
• Default Native VLAN is Vlan1.

Advantages of VLAN

• A VLAN is a single broadcast domain which means that if a user in the one VLAN would send a broadcast frame, only users in the same VLAN will receive it.
• Users are only able to communicate within the same VLAN.
• Users don’t have to be grouped physically together, as you can see we have users in the one VLAN sitting on the 1st, 2nd and 3rd floor can also communicate.

Ethernet Frame VLAN Format

• As you can see, we have TAG field in between the normal Ethernet Frame format.
• This is the field, where VLAN has been assigned in the Ethernet frame.

Ports in VLAN

• Trunk 
• More than one VLAN can be assigned to trunk port.
• Trunks port will be used between the Switches
• Access
• Only one VLAN will be allowed in access port.
• Access port will be used while connecting to the host.

Characteristics of VLAN

• VLAN information is not saved in the running-config or startup-config but in a separate file called vlan.dat on your flash memory. 
• If you want to delete the VLAN information, you should delete this file by typing delete flash:vlan.dat.

DTP- Dynamic Trunking Protocol

• The negotiation of the switch-port status by using dynamic auto or dynamic desirable is called DTP (Dynamic Trunking Protocol).
• Here the Switch will dynamically take its port Status as access or Trunk based on the dynamic configuration in switch port.

Overview Of Switch-port Modes

You can also Look into my Video Tutorial

That's it about VLAN and DTP