Cluster-1  
                            +-----------+
                            |  Tier-1   |
                            |  +-----+  |
                            |  |NODE |  |
                            |  |  5  |  |
                 Cluster-2  |  +-----+  |  Cluster-3
                +---------+ |           | +---------+
                | Tier-2  | |           | |  Tier-2 |
                | +-----+ | |  +-----+  | | +-----+ |
                | |NODE | | |  |NODE |  | | |NODE | |
                | |  3  | | |  |  6  |  | | |  9  | | 
                | +-----+ | |  +-----+  | | +-----+ |
                |         | |           | |         |
                |         | |           | |         |
                | +-----+ | |  +-----+  | | +-----+ |
                | |NODE | | |  |NODE |  | | |NODE | |
                | |  4  | | |  |  7  |  | | |  10 | |
                | +-----+ | |  +-----+  | | +-----+ |
                +---------+ |           | +---------+
                            |           |
                            |  +-----+  |         
                            |  |NODE |  |      
          Tier-3            |  |  8  |  |         Tier-3       
      +-----+ +-----+       |  +-----+  |      +-----+ +-----+ 
      |NODE | |NODE |       +-----------+      |NODE | |NODE | 
      |  1  | |  2  |                          | 11  | |  12 | 
      +-----+ +-----+                          +-----+ +-----+