Cisco Certification Exam Review:
VLAN Trunking Protocol (VTP)
By Chris Bryant, CCIE #12933
You recall from your CCNA studies that VTP allows a network's switches to have a consistent view of the VLANs in the network. Other VTP fun facts:
VTP is a Cisco-proprietary messaging protocol.
VTP runs at Layer 2 of the OSI model.
VTP is a multicast protocol (destination 01-00-0C-CC-CC-CC, the same used by CDP).
A switch can be in only one VTP domain.
Once you get VTP up and running, it can run for a very long time with no additional configuration, but every once in a while you can run into trouble getting started.
In my experience, VTP problems really come down to two things: password and mode misconfigurations.
I'm not big on using VTP passwords, since they're about as non-secure as it gets:
SwC#show vtp password
VTP Password: CCIE
But if you didn't know how to find a VTP password, now you do! You recall from your CCNA studies that we've got three different VTP modes - server, client, and transparent - and that VLANs cannot be created on a VTP client. The switch tells us that, but Cisco exams probably will not. : )
VTP VLAN configuration not allowed when device is in CLIENT mode.
To your success,