Hi guys?

I have a clarifications on VTP pruning mode? Why it is useful for switches. and when we use the pruning mode?
kindly give me a clarification of pruning mode.
Thanks in advance.

Hi,

Basically VTP pruning allows you NOT to send frames coming from a particular VLAN to the switches where, there are no ports assigned to that specified VLAN.

Example:
[SW1]--[SW2]--[SW3]

All links between switches are manually configured as trunk
VLANs created by VTP to all switches: 5,6,7 (assuming that all of them are joining the same VTP domain with SW1 as server and the rest as clients, to be sure that all has the same vlans)

SW1 has ports in VLAN: 5,6 and 7
SW2 has ports in VLAN: 5,6 and 7
SW3 has ports in VLAN: only 7

VTP pruning will block any frames coming from SW2 tagged as VLAN 5 and 6 to enter SW3, but will allow frames coming as VLAN 7
this because SW3 has no ports configured in access mode for those VLANS (5 and 6)
But between SW1 and SW2 is has no effect because those 2 switches has ports to all VLANs

More info -> http://www.google.com/webhp#hl=en&q=vtp+pruning

I hope this was informative for you and I like to thank you for reading ;)
Cheers!

Thank you.