VLAN Trunking Protocol (VTP) | VTP Modes | Server Mode | Transparent Mode

 

        VTP Trunking Protocol:- VLAN Trunking Protocol (VTP) is a Cisco layer-2 message protocol that manages the addition, deletion, and renaming of VLANs on a network-wide basis.

VLAN Trunking Protocol (VTP) Protocol reduces network admin work.

When you configure a new VLAN on one VTP server the VLAN is distributed through all switches in the domain.

This reduces the need to configure the same VLAN everywhere.

VTP is a Cisco proprietary protocol that is available on most of the Cisco switches.

Requirement of VTP:-

                            1.)VTP domain name must be the same on all switches

                            2.)Link between switches must be configured as Trunk.

                            3.)Password must match (optional)

                            4.)VTP Version must match on all switches.

VTP Modes:-

                        1.)Server Mode (Default Mode) 

                        2.)Client Mode

                        3.)Transparent Mode(Default Mode)

1.)Server Mode:- We can create Vlans, Delete Vlans and edit Vlans.

                        It generates VTP update messages.

                        It works as the relay agent.

                        It stores its Vlans database in a vlan.dat file in flash memory.

2.)Client Mode:- We can NOT create Vlans, Delete Vlans and edit Vlans.

                        It generates VTP update messages.

                        It receives Vlans information from server mode switches and it will update its VLAN database.

3.) Transparent Mode:- This mode switches can not update their vlan database from the VTP update message.

                                 VTP transparent mode switches can receive and forward VTP advertisements through the configured trunk links.

                                 VLAN Trunking Protocol (VTP) transparent mode switches do not participate in the VTP domains.

Configuring VTP for VLAN propagation:-

VTP

 By Default VTP status on switches:- 

Switch>sh vtp status

VTP Version capable : 1 to 2

VTP version running : 1

VTP Domain Name :

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : 0002.165C.4300

Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00

Local updater ID is 0.0.0.0 (no valid interface found)

Feature VLAN :

--------------

VTP Operating Mode : Server

Maximum VLANs supported locally : 255

Number of existing VLANs : 5

Configuration Revision : 0

MD5 digest : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A

0xF0 0x58 0x10 0x6C 0x9C 0x0F 0xA0 0xF7 

Note:- As you can see that VTP Domain name is not present. So we will configure domain name first on first switch & for other switches we will configure trunk port.

    So lets start

Step:1 [Create Domain Name]

================================================

Switch>en

Switch#configure terminal

Switch(config)#vtp domain Tosif

Changing VTP domain name from NULL to Tosif

Domain Creation done now

================================================

Switch>sh vtp status

VTP Version capable : 1 to 2

VTP version running : 1

VTP Domain Name : Tosif

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : 0002.165C.4300

Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00

Local updater ID is 0.0.0.0 (no valid interface found)

Feature VLAN :

--------------

VTP Operating Mode : Server

Maximum VLANs supported locally : 255

Number of existing VLANs : 5

Configuration Revision : 0

MD5 digest : 0xD3 0xA0 0xC7 0x69 0x70 0xDE 0x83 0x07

0x9D 0x2E 0x4B 0xC5 0x11 0x00 0xB6 0x4A

Note:- As you can see that Domain name is present now.

================================================

Switch>sh vtp counters

VTP statistics:

Summary advertisements received : 0

Subset advertisements received : 0

Request advertisements received : 0

Summary advertisements transmitted : 0

Subset advertisements transmitted : 0

Request advertisements transmitted : 0

Number of config revision errors : 0

Number of config digest errors : 0

Number of V1 summary errors : 0

VTP pruning statistics:

Trunk Join Transmitted Join Received Summary advts received from

non-pruning-capable device

---------------- ---------------- ---------------- ---------------------------

Note:- As you can see that Switches are not transmitting or receiving packet at this time. So this is showing "0".

==================================================

Step2:Creating Links between switches as a Trunk. But first we check VTP status on the Switch2

Switch2>sh vtp status

VTP Version capable : 1 to 2

VTP version running : 1

VTP Domain Name :

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : 0090.2B3C.1D00

Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00

Local updater ID is 0.0.0.0 (no valid interface found)

Feature VLAN :

--------------

VTP Operating Mode : Server

Maximum VLANs supported locally : 255

Number of existing VLANs : 5

Configuration Revision : 0

MD5 digest : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A

0xF0 0x58 0x10 0x6C 0x9C 0x0F 0xA0 0xF7 

Note:- This switch is not showing domain name because port between switches are not configured as a Trunk yet.

Lets Start:- Check connected link on this switch.

Switch2>sh cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device ID    Local Intrfce  Holdtme   Capability    Platform    Port ID
Switch1       Gig 0/1              166             S              2960        Gig 0/1
Switch3      Gig 0/2              178             S             2960         Gig 0/1

These ports/links are connected on this switch. So let them configure as a Trunk.

Switch2(config)#interface range Gig 0/1,Gig 0/2

Switch2(config-if-range)#switchport mode dynamic desirable

Switch2(config-if-range)#no shutdown

Port configured as Trunk. Now check VTP status on Switch2.

Switch2>sh vtp status
VTP Version capable : 1 to 2
VTP version running : 1
VTP Domain Name : Tosif
VTP Pruning Mode : Disabled
VTP Traps Generation : Disabled
Device ID : 0090.2B3C.1D00
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Local updater ID is 0.0.0.0 (no valid interface found)
Feature VLAN :
--------------
VTP Operating Mode : Server
Maximum VLANs supported locally : 255
Number of existing VLANs : 5
Configuration Revision : 0
MD5 digest : 0xD3 0xA0 0xC7 0x69 0x70 0xDE 0x83 0x07
0x9D 0x2E 0x4B 0xC5 0x11 0x00 0xB6 0x4A 

Note:- As you can see that after creating port as Trunk Domain name automatically shown on Switch2.

On Switch3 it is also showing.

Switch3>sh vtp status
VTP Version capable : 1 to 2
VTP version running : 1
VTP Domain Name : Tosif
VTP Pruning Mode : Disabled
VTP Traps Generation : Disabled

Device ID : 0005.5E91.D400
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Local updater ID is 0.0.0.0 (no valid interface found)
Feature VLAN :
--------------
VTP Operating Mode : Server
Maximum VLANs supported locally : 255
Number of existing VLANs : 5
Configuration Revision : 0
MD5 digest : 0xD3 0xA0 0xC7 0x69 0x70 0xDE 0x83 0x07
0x9D 0x2E 0x4B 0xC5 0x11 0x00 0xB6 0x4A

Now VTP counter value has been changed. Lets check it

Switch2#sh vtp counters
VTP statistics:
Summary advertisements received : 90
Subset advertisements received : 4
Request advertisements received : 0
Summary advertisements transmitted : 45
Subset advertisements transmitted : 2
Request advertisements transmitted : 0
Number of config revision errors : 0
Number of config digest errors : 0
Number of V1 summary errors : 0

VTP pruning statistics:
Trunk Join Transmitted Join Received Summary advts received from
non-pruning-capable device
---------------- ---------------- ---------------- ---------------------------

Now we will create VLAN on Switch1. You will see that same VLAN create automatically on Switch2 & Switch3 as well as.

Switch1>en

Switch1#configure terminal

Switch1(config)#vlan 50

Switch1(config-vlan)#name HR

Switch1(config)#ex

Switch1#sh vlan

VLAN Name         Status                 Ports

---- -------------------------------- --------- -------------------------------------------------------

1        default         active                Fa0/1, Fa0/2, Fa0/3, Fa0/4

                                                     Fa0/5, Fa0/6, Fa0/7, Fa0/8

                                                     Fa0/9, Fa0/10, Fa0/11, Fa0/12

                                                     Fa0/13, Fa0/14, Fa0/15, Fa0/16

                                                     Fa0/17, Fa0/18, Fa0/19, Fa0/20

                                                     Fa0/21, Fa0/22, Fa0/23, Fa0/24

                                                     Gig0/2

50       HR             active

--------------------------------------------------------------------------------------------------------

Switch2#sh vlan

VLAN Name         Status                 Ports

---- -------------------------------- --------- -------------------------------

1        default         active                Fa0/1, Fa0/2, Fa0/3, Fa0/4

                                                     Fa0/5, Fa0/6, Fa0/7, Fa0/8

                                                     Fa0/9, Fa0/10, Fa0/11, Fa0/12

                                                     Fa0/13, Fa0/14, Fa0/15, Fa0/16

                                                     Fa0/17, Fa0/18, Fa0/19, Fa0/20

                                                     Fa0/21, Fa0/22, Fa0/23, Fa0/24

                                                     Gig0/2

50       HR             active (Automatically Created)

-----------------------------------------------------------------------------------------------

Switch3#sh vlan

VLAN Name         Status                 Ports

---- -------------------------------- --------- -------------------------------

1        default         active                Fa0/1, Fa0/2, Fa0/3, Fa0/4

                                                     Fa0/5, Fa0/6, Fa0/7, Fa0/8

                                                     Fa0/9, Fa0/10, Fa0/11, Fa0/12

                                                     Fa0/13, Fa0/14, Fa0/15, Fa0/16

                                                     Fa0/17, Fa0/18, Fa0/19, Fa0/20

                                                     Fa0/21, Fa0/22, Fa0/23, Fa0/24

                                                     Gig0/2

50       HR             active (Automatically Created)

-----------------------------------------------------------------------------------------------

Note:- By default all the switch is in Server mode. As we have discussed above that any update on the server will effect all the switch which is connected.

We can change its type server mode to Client or Transparent mode.

Let see how

Switch3>en

Switch3#configure terminal

Switch3(config)#vtp mode client

Setting device to VTP CLIENT mode.

Switch3#sh vtp status

VTP Version capable : 1 to 2

VTP version running : 1

VTP Domain Name : Tosif

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : 0005.5E91.D400

Configuration last modified by 0.0.0.0 at 3-1-93 04:31:39

Feature VLAN :

--------------

VTP Operating Mode : Client

Maximum VLANs supported locally : 255

Number of existing VLANs : 6

Configuration Revision : 2

MD5 digest : 0xC3 0x72 0x99 0x8A 0x62 0xFF 0x3A 0xB5

0x71 0xB9 0x8F 0xCD 0x85 0x7A 0x36 0x61 

Now Mode has been changed to Client.