          <===Network Provider===>
   
   +----+ from X1:x1 to X2':x2'   +-----+ X1':x1'
   | C1 |>>>>>>>>>>>>>>>>>>>>>>>>>>>>>--+---
   +----+                         |  v  |
                                  |  v  |
                                  |  v  |
                                  |  v  |
   +----+ from X1':x1' to X2:x2   |  v  | X2':x2'
   | C2 |<<<<<<<<<<<<<<<<<<<<<<<<<<<<<--+---
   +----+                         +-----+
                                 Converter
   
   Note: X2':x2' may be equal to
         X2:x2