Purely theoretically, the VTP Transparent mode prevents a switch from sending any VTP packets, so the Transparent mode is indeed the most bandwidth saver.
However, even with VTP Server or Client modes, the bandwidth consumption is absolutely negligible. In a stable network where no changes to the VLAN database are being performed, switches only send the VTP summary advertisements in intervals of 5 minutes. From this viewpoint, a spanning tree protocol consumes far more bandwidth (and even with STP, the actual bandwidth consumption is negligible).
VTP Transparent mode will not reduces bandwidth by default. It will forward all VLAN out to the trunk port with the default configuration. However, you can manually prune VLAN's that you don't want on a trunk link with the following interface level command:
To allow VLAN x,y,z
switchport trunk allowed vlan x,y,z
To remove VLAN a,b,c
switchport trunk allowed vlan remove a,b,c
You can do the same thing with VTP Server/Client mode with VTP prune turned on.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...