seqdiag {
    node_width = 100;
    edge_length = 115;

    "Client"
    "Controller"
    "Conductor"
    "VnflcmDriver"
    "InfraDriver"
    "CommonUtils"
    "Database"

    Client -> Controller
      [label = "HTTP request (e.g. VNF Lifecycle Management)"];
    Controller -> CommonUtils
      [label = "Process common logic"];
    Controller <-- CommonUtils
      [label = ""];
    Controller -> Database
      [label = "Validate request with appropriate API version"];
    Controller <-- Database
      [label = ""];
    Controller -> Database
      [label = "Create VnfLcmOpOcc(STARTING)"];
    Controller <-- Database
      [label = ""];
    Controller -> Conductor
      [label = "Send RPC"];
    Client <-- Controller
      [label = "202 Accepted"]
    Conductor -> VnflcmDriver
      [label = "Invoke VnflcmDriver with appropriate API version"];
    VnflcmDriver -> CommonUtils
      [label = "Process common logic"];
    VnflcmDriver <-- CommonUtils
      [label = ""];
    VnflcmDriver -> Database
      [label = "Update VnfLcmOpOcc(PROCESSING)"];
    VnflcmDriver <-- Database
      [label = ""];
    VnflcmDriver -> InfraDriver
      [label = "Invoke InfraDriver with appropriate API version"];
    VnflcmDriver <-- InfraDriver
      [label = ""];
    VnflcmDriver -> CommonUtils
      [label = "Process common logic"];
    VnflcmDriver <-- CommonUtils
      [label = ""];
    VnflcmDriver -> Database
      [label = "Update VnfLcmOpOcc(COMPLETED)"];
    VnflcmDriver <-- Database
      [label = ""];
    Conductor <-- VnflcmDriver
      [label = ""];
  }