<----G.8032----><--PBB-EVPN Network-----><----MPLS---->
     Access          MPLS                Access  
      Ring                               Network
I-SID1      ESI +------+         +------+
+----+      null| PE1  |---------| PE3  |
|CE1 |----------|B-MAC1|         |B-MAC3| ESI null
+----+    active|      |         |      |----+ PW     
  |             +------+         +------+     \active  
  |               |                 |          \  +----+
  |               |                 |           ==|CE3 |I-SID1
  |               |                 |          /  +----+
  |standby  ESI +------+         +------+     / PW   
+----+      null| PE2  |         | PE4  |----+ standby      
|CE2 |----------|B-MAC2|         |B-MAC4| ESI null
+----+    active|      |---------|      |
I-SID1          +------+         +------+