Logically, it's either bus or ring.
Physically... everything goes.
No bus or ring, break one and everything breaks.
For star, the main weakness is the router, switch and hub. That one
goes down, everything goes down...
The best is still a mesh... whether a full or partial mesh, will
depend on what is needed.
And I wonder if you are a clone. There has been 3 questions on WAN
topologies.