seqdiag {
    Client -> "tacker-server" [label = "LCM Operation Request"];
    Client <-- "tacker-server" [label = "Response 202 Accepted"];
    "tacker-server" -> "tacker-conductor"
      [label = "trriger asynchronous task"];
    "tacker-conductor" ->> "tacker-conductor"
      [label = "execute notification process"];
    Client <- "tacker-conductor"
      [label = "POST {callback URI} (PROCESSING)"];
    Client --> "tacker-conductor" [label = "Response: 204 No Content"];
    "tacker-conductor" -> "VnfLcmDriver" [label = "execute MgmtDriver"];
    "tacker-conductor" <-- "VnfLcmDriver" [label = ""];
    "tacker-conductor" -> "VnfLcmDriver" [label = "execute VnfLcmDriver"];
    "tacker-conductor" <-- "VnfLcmDriver" [label = ""];
    "tacker-conductor" ->> "tacker-conductor"
      [label = "execute notification process"];
    Client <- "tacker-conductor"
      [label = "POST {callback URI} (COMPLETED)"];
    Client --> "tacker-conductor" [label = "Response: 204 No Content"];
  }