Jul/090
VTP: VLAN Trunking Protocol
VTP, What is it. VTP is a protocol created to ease the creation of VLANs on multiple switches, in an environment where there are multiple switches, its easier to setup a single switch as a sort of master switch that tells all of the other switches out on the network, hey, here’s all your VLANs.
Great idea, now for the drawbacks:
1) in VTP adding new switches can be a rather dangerous affair if you’re not careful. Every switch in the network maintains a revision number, and the server (or the client) with the highest revision number in a VTP domain can cause other VLANs to suddenly disappear.
2) Only support VLANs 1-1005, no extended VLAN (1006-4096) support, at least in VTP version 1 and Version 2. Version 3 is currently only supported by CatOS 8.1 and above.
3) VTP shouldn’t be used on sensitive core switches, should be kept in transparent mode.