FTP Active Data Transfer Subflow


This message flow is used as a subflow in the FTP Active Data Transfer Mainflow DMF, and it simulates a file downloaded from the Network Host node to the MN. The subflow executes once in every mainflow transaction.

The server establishes a TCP connection with the client port defined in the subflow. When the connection is established, the subflow sends a TRANS_START event to the mainflow, allowing it to continue with the retrieve command. The subflow then waits to receive a TRANS_START event from the mainflow.

  1. The server sends a 78-byte packet containing Zs and terminated with a CR-LF pair.

After the data transfer is received, a TRANS_COMPLETE event is sent to the mainflow, and the subflow waits for a SUBFLOW_STOP event. When the event is received, the client closes the TCP connection.

NOTES:

  • This message flow is designed to be used as a subflow and should not be used as a mainflow.
  • Steps 1 and 3 are blank commands used for padding since message flows cannot begin or end with event controls.

Modifying the Message Flow

You can modify the message content or import a file to be used as the message.

The defined Client Port is used to provision the PORT command in the mainflow.

You can specify that random port numbers, in the IANA specified dynamic range of 49152 — 65535, be assigned when the subflow executes by entering a 0 for either Client Port or Server Port.