The user data segment contains a user message and a priority value where the priority value conveys a corresponding message priority to a recipient device.

The ASC mapping may be based on message priority and logical channel priority.

The method includes assigning a message priority to each of a plurality of trade messages to communicate to the exchange.

Visual indicia indicative of a current message priority to be assigned to the user message is displayed on the composition.

The first module causes insertion of the priority value corresponding to the current message priority in a priority field in the user data segment prior to transmission of the digital packet.