Introduction to VTP (VLAN Trunking Protocol)

Hello Mario

That’s a good question. I went into the lab and checked this out. I have found that on transparent switches, the revision number always remains zero. Even though I added several VLANs to this switch, you can see that this is so:

SW1#show vtp statu
*Nov  9 06:38:55.759: %SYS-5-CONFIG_I: Configured from console by consoles
VTP Version capable             : 1 to 3
VTP version running             : 2
VTP Domain Name                 : 
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 5254.0006.8000
Configuration last modified by 0.0.0.0 at 11-9-22 06:37:31

Feature VLAN:
--------------
VTP Operating Mode                : Transparent
Maximum VLANs supported locally   : 1005
Number of existing VLANs          : 14
Configuration Revision            : 0
MD5 digest                        : 0xD8 0x87 0x4A 0xF5 0x0D 0x70 0x90 0x91 
                                    0x65 0x54 0x4B 0x9F 0x2A 0xC2 0x95 0xCC 
SW1#

This means that even local changes made do not change the revision number of the transparent switch, nor do any VTP messages that a transparent switch may receive and relay to other switches. This makes sense, because a revision number has no meaning for a transparent switch from the moment that its VLAN configuration remains completely independent of any other switch on the network.

I hope this has been helpful!

Laz