My CISCO Journal

VLAN Trunking Protocol (VTP) – The Good VS the Bad Part 2:

Taking after are the parameters needed for the VTP gadgets to impart:

1-VTP Domain name

2-VTP Password: VTP uphold confirmation utilizing passed which is hashed as MD5 and utilized within VTP commercials over the system.

It would be ideal if you note that the Domain name and Password must match on the VTP empowered switches or VTP should not work giving Domain & Password jumble mistakes.

Alright at long last we are finished with the hypothesis. So how about we begin with our best, “The Configurations”.

In this arrangement we are sure to utilize 4 switches with SWITCH-1 as the VTP server while the alternate 3 will serve as VTP clients. So we should begin then;

In the wake of joining the switches we need to prepare trunk mode on the switch nearby ports on account of it is essential for the traversal of VLAN traffic.

SWITCH-1(config)#inter fa 0/1

SWITCH-1(config-if)#switchport trunk encapsulation do

SWITCH-1(config-if)#switchport trunk encapsulation dot1q

SWITCH-1(config-if)#switchport mode trunk

Note: It is not needed to run the command to initiate the trunk on the alternate close of the connection for as much as it is auto initiated when prepared toward one side.

Not with standing actuate trunk on the greater part of the switches for VLAN movement stream with the above given command. In the wake of empowering trunk mode, we will arrange VTP-Server mode on SWITCH-1 and VTP-Client mode on the remaining switches.

Since the default VTP mode on the switches is ‘Server’, we don’t need to update any of the above SWITCH-1 for server mode:

SWITCH-1#show vtp status

The above command will display different VTP parameter status, whether they are enabled or not.

Now, we will enable client mode on the other switches and will move on to configure VTP Domain name, password and version.

And we will issue the above mentioned show vtp status command to check whether our switch has been configured as client switch or not.  

Repeat the steps for all switches and enable VTP client mode of the switches. Now let’s make some change on the VTP server and check the results on the client.

Now let’s check the VLAN and VTP status on the VTP-clients and feel the magic:

This is all that you need to accomplish for VTP on our switches. Straightforward right? So attempt it and have a great time.   Just keep one thing in mind , never try to plug any switch in your office cubicle to your live network, before knowing the complete detail about your network as this enthusiasm can cost you a lot. One other thing we must keep in mind, never to plug any switch from our corporate lab into our live network, as mostly we do different sort of experiments on these switches and if anyone of them have higher revision number and same domain unluckily then you will have to spend the whole weekend in office troubleshooting the network!  So we have covered one of the major concept related to switching technologies, we will keep our journey on, will stay foolish and stay hungry.

VTP is an absolutely fascinating thought however meanwhile quite hazardous if not took care of with delicacy. I know you may be suspecting WHY? For your response and to perceive the notion wouldn't it be great if we could start then and I welcome you to the universe of VTP.

VTP in true is an update methodology. It gives an intend to make VLANs on associated switches as an assembly and it is particularly supportive in hefty organizes. Assuming that VTP is empowered on the sum of your Cisco switches, the production of another VLAN on one switch makes that VLAN ready on all switches with the same VTP administration area. Befuddled? Well don’t be.

Give me a chance to illustrate in straight forward statements, case in point, you have a huge system with different switches with VLANs, supporting diverse clients and suddenly you are asked to include more accommodates in the system on another switch(s) on numerous VLANs, With the augmentation of another switch(s) you need to arrange the sum of the VLANs again and trust me this is sure to require some serious energy. Anyhow don’t be startled, we have VTP to bail us out. At the point where VTP is prepared, it will do VLAN update on the switches for us and will make the unique included VLAN the sum of the switches. Energizing and jaw-dropping right?

Presently how about we check the perilous part. Envisage it is a marvelous day and you come to work and blissful to see the whole grid is working fine, you are asked to instate another switch in the arrangement which was a utilized one and you unequivocally add the switch to the system. Suddenly things are not the same as they were and this seems to be, Well! VTP is action. Why?

 See you had VLANs on your grid as e.g. 1, 2,3,4,5 soon after the unique switch(s) were instated having VLAN we should state 3012. So what VTP is doing, it checks and discover that there is VLAN 3012 in the system now and all different switches are on VLAN:1,2,3,4,5 , it eradicates all of these 1,2,3,4,5 VLANs, makes VLAN:3012 and you lose your arrangement recognizing blackout till you track the issue.

VTP Versions

There are numerous adaptations of VTP.

VTP-v.1 and 2 are relative with the sole uniqueness that shape 2 incorporates back for token ring frameworks. VTP structure 3 is novel and is unequivocally exceptional to go ahead CatOS-8.1 or higher.

VTP Modes of Operation

Accompanying are the VTP modes of operation that are allotted to every VTP unit: 

1-Server: The mechanism having the “Server” mode of operation is fit to design, include and    erase VLANs as well as the design of VTP form, VTP pruning and confirmation.

Note: The default switch VTP mode is ‘Server’

2-Client: VTP clients are not ready to make any design updates noticing the VLANs. The client apparatus actually takes parameters from the server and executes it in the database.

3-Transparent: VTP transparent mode gadgets don't tune in VTP as the name states they are transparent. They actually promote VTP over the grid.

It is remarkably proposed not to keep more than one switch in server mode for VTP on the grounds that when you include increasingly server roles in the grid, you are expanding the danger element as anybody can update any VLAN information and it will be advertised over the network and you will end up forgetting the start and end point and this is where VTP becomes your enemy.