USB Missing Decode Information
The system usually determines the protocol carried in an USB payload by monitoring previous traffic. However, when this doesn't happen, the Missing Decoding Information Detected dialog appears and requests that the user supply the missing information.
The following are the most common reasons for a failure to determine the traversal:
- the capture session started after transmission of the vital information
- the analyzer incorrectly received a frame with the traversal information
- the communication monitored takes place between two players with implicit information not included in the transmission
Whatever the case, there are several things to keep in mind.
- Either view the USB payload of this frame (and other frames with the same address) as hex data, or assist the analyzer by selecting a protocol using this dialog.
- You may use the rest of the analyzer without addressing this dialog. Additional information gathered during the capture session may help you decide how to respond to the request for decoding information.
- If you are not sure of the payload carried by the subject frame, look at the raw data shown under “data” in the detail pane on the frame display. You may notice something that hints as to the profile in use.
- In addition, look at some of the frames following the one in question. The data may not be recognizable to the analyzer at the current point due to connection setup, but might be discovered later on in the capture.