+------+   +------+          
| eNB1 |---| CSG1 |\
+------+   +------+  \   +-------+       +------+           +-------+
               |       \ |  ASG1 |-------| RSG1 |-----------|SGW/MME|
               |  Ring2  +-------+       +------+ \        /+-------+
+------+   +------+     /     |              |      \    /         
| eNB2 |---| CSG2 | \  /      |      Ring1   |        \/
+------+   +------+   \  Ring3|              |        /\      
                     / \      |              |      /   \  
+------+   +------+ /    \ +-------+      +------+/       \+-------+
| eNB3 |---| CSG3 |--------|  ASG2 |------| RSG2 |---------|  RNC  |
+------+   +------+        +-------+      +------+         +-------+