About the Message Editor Window

The Message Editor gives you the ability to define any type of message from a simple packet with a specific number of bytes using one of the provided protocols to a message that defines the headers and payload for a custom protocol. You can include dynamic content that is unique for each message flow, packet, or MN, define any required binary encoding, and import files for use as payloads.

Static Content

You can explicitly define some or all of the message content on the Hex-Ascii, Text Editor amd MQTT Helper sub-tabs. These editing sub-tabs are normally used to define application-level control messages, as shown in the FTP example above, and to define packet headers for custom protocols. When you insert dynamic content in the message, it is inserted into this portion of the message. A maximum of 1500 bytes can be defined on these sub-tabs, and the available bytes remaining is displayed above the ASCII portion of the Hex-Ascii sub-tab. You can also import a text file to use for this portion of the message with the Browse button.

Use the Hex-Ascii tab to compose the message if the protocol is not text-based. The left column displays the row number, the center column displays the hex value of the bytes arranged by row and byte position, and the right column displays the ASCII translation. Values that cannot be represented by an ASCII character are shown with a square.

• Select a byte, and the row number, byte, and ASCII character are highlighted. When a byte is selected, you can modify its value. The character that will be modified is highlighted in blue. Byte editing always begins with the left nibble — you cannot edit only the right nibble.

• ASCII characters can be edited in the ASCII portion of the sub-tab.

• Use the Mode button (above the row numbers) to toggle between Overwrite (default) and Insert mode, or use the Insert key on your keyboard to toggle the editing mode. When you use Insert mode, bytes are pushed to the right as you type.

• You can also add to the message by right-clicking and selecting Paste from the context menu.

• Use the Delete key to delete the selected byte, and the Backspace key to delete the previous byte.

• Navigate through the bytes with arrow keys, jump to the first byte with the Home key, or jump to the last byte with the End key.

• Insert carriage return or line feed characters at the selected byte with the Insert CR or Insert CRLF buttons or by right-clicking at the insertion point and selecting the option from the context menu.

Use the Text Editor tab to compose the message in plain text. The text in the Text Editor is converted to hex, and you can still use the Hex-Ascii tab to insert bytes for any encoding that the protocol requires. The example to the right shows the hex message used above in the Text Editor.

• You can insert carriage return or line feed characters with the Insert CR or Insert CRLF buttons or by right-clicking at the insertion point and selecting the option from the context menu.

• Paste from the clipboard by right-clicking and selecting Paste from the context menu.

• You can use keys to navigate through the text as you would in a word processor: scroll through characters with the arrow keys, jump from word to word with Ctrl-arrow key combinations, go to the beginning or end of a line with the Home and End keys, or go to the beginning or end of the message with the Ctrl-Home and Ctrl-End key combinations.

If text can be used in the message without regard to the content, you can use the Automatic setting in the Filler Data pane to pad the message with "Z" characters. You can start the filler at a particular byte (Content Start) and define the total size of the final message, including any dynamic content inserted into the message and the literal portion of the message defined on the editing sub-tabs, with Content Size. The Auto-Fill Viewer sub-tab (see the Dynamic Content section below) displays the placeholder for the filler data positioned within the message content as specified.

With the Test Data File setting, you can select a data file that has been imported into your Test Library, and the file will be inserted into the message beginning at Content Start. Data files can be up to 500KB (512,000 bytes) and can contain text, graphic, or multimedia data. If there is any overlap between filler data and bytes defined on the editing tabs, the remaining bytes from the editing tabs are appended to the filler data.

When the message's total size is larger than the Segment Size defined for the DMF, the message will be sent using multiple packets. If you have defined header fields in the editing sub-tabs, this information will be included in every packet when you check Include All Data Before Content Start As Header In Every Segment.

Use the MQTT Helper tab to compose messages that are supported by the mqtt protocol. For mqtt protocol, the text and auto-fill tabs are not available. The message format is a combination of binary and ASCII.

• Select Control Packet Type:

• Based on the Control Packet type, various input fields will become available to generate the mqtt messages.

• For example, a SUBSCRIBE message type, capture input for : Packet ID, capture up to 20 Number of Topics. For a CONNACK message type, enable Session Present and select the Return code.

• Go to mqtt.org for further details on the mqtt supported messages.

• NOTE: Added the ability to modify MQTT parameters by enabling the Text and Auto-Fill Editor tabs for MQTT protocol. First create messages with MQTT Helper, and when done, add the paste buffers. When the paste buffers are added to the messages, MQTT Helper can no longer parse that message. The paste buffers should be input into DMF test data file. The paste buffers for this feature are as follows : Mqtt Connect: Paste buffer 1: Client Id (example: Subscriber_#) Mqtt Subscribe: Paste buffer 2-5: Topic Name and requested QoS (example: Plano/Spirent@1) Mqtt Unsubscribe: Paste buffer 9: Topic Name (no QoS value) Mqtt Publish: Paste buffer 9: Topic Name (no QoS value) Paste buffer 10: Application Message

   

Dynamic Content

You can use Auto-Fill Fields to insert values that are unique to the MN, the MN's data session, or the message flow into your message. Fields are also provided that enable you to capture a value from a received message — the session ID or the port to be used for a data connection, for example — and insert it into subsequent messages or use it to provision other settings in the test. Defined fields are listed in the Auto-Fill Fields pane and are also displayed, embedded within the message content, on the Auto-Fill Viewer sub-tab as shown in the example. Fields that insert content are shown in red and fields that capture content are shown in yellow.

You can use the Add and Remove buttons to manage the fields, and you can also add new fields by using the context menu. Right-click in one of the editing sub-tabs, select Add Auto-Fill, and a field is added at that position. If you select a series of characters in the Text Editor sub-tab first, the field will replace the selected characters.

The position of a field that inserts content is defined by its Offset. Fields that capture values from a message can be targeted by position using Offset or they can use a Search Pattern to find the target anywhere in the message. The Current Offset of your cursor is displayed near the tops of both editing sub-tabs, and it can aid you in confirming the exact placement of a field. If you add content to the editing sub-tabs after adding fields, any affected Offset values are automatically adjusted, keeping them in the same position relative to the surrounding content.

See Auto-Fill Fields for more information about the types of fields available and how you can use them in a test.