4.1 Transport Layer Responsibilities

1. Commands are generated by the Firmware Update Protocol Layer and passed to the Transport Layer.
2. Commands are sent over the communications bus from the host to the client.
3. The client Transport Layer receives the commands and verifies their integrity before passing them to the Firmware Update Protocol Layer.

   

1. The client’s Firmware Update Protocol Layer generates responses and passes them to the Transport Layer.
2. Responses are sent over the communications bus from the client to the host.
3. The host’s Transport Layer retrieves responses and verifies their integrity before passing them up to the host’s Firmware Update Protocol Layer.

   

• The MDFU Protocol places the responsibility of detecting corruption in commands/responses (i.e. bit flips due to noise) on the Transport Layer
• When corruption is detected, the Firmware Update Protocol Layer is notified so that the error recovery mechanisms can be utilized to recover from these errors

Hosts use a time-out to recover from commands or responses that are lost. Hosts can choose whether they want to implement that time-out in the host Firmware Update Protocol Layer or the host Transport Layer. See Host Command Generation and Response Processing for more details.