Hello Helen
The reason I mentioned broadcast domains here is because in your previous post you said:
The communicate between the different VTP domain should consider as layer 3 now, correct?
Unless I misunderstood, you also seemed to indicate that communication between VTP domains would require routing, thus each VTP domain would correspond to a broadcast domain or a network segment.
I may have misunderstood your initial comments, but in any case, the point I was trying to make is that VTP will only communicate between switches at Layer 2, and only via trunks. There are no IP addresses involved with VTP, regardless of whether you are using the same or different VTP domain names, and regardless of the subnets assigned to each VLAN. VTP packets will be sent out of all trunk ports, regardless of the domain being used. VTP is always sent untagged and uses VLAN1 as stated in this post.
The topology you have created will function correctly, and the experiment you did by deleting the VLAN in SW3 resulting in the expected behaviour. Functionally, this will work, however, the question remains, why would you do this? What is the purpose behind having multiple VTP domains administrating the same set of VLANs? As far as I can see, there is no benefit.
The primary problem with this is the complexity of administration this adds, which also increases the potential for mistakes. By doing it this way, you need to make changes to the specific VLAN in both domains separately. Because the primary purpose of VTP is to be able to sync VTP creation deletion and management, introducing two VTP domains to administer the same VLANs simply reverts back to having to apply the same thing multiple times. You can do it, but I can see no reason to do so.
I hope this has been helpful!
Laz