In previous work, it has been shown how to solve atomic broadcast by reduction to consensus on messages. While this solution is theoretically correct, it has its limitations in practice, since executing consensus on large messages can quickly saturate the system. The problem can be addressed by executing consensus on message identifiers instead of the full messages, in order to decouple the size of the messages from the size of the data sent by the consensus algorithm. In this paper, we study the impact of executing consensus on message identifiers instead of on the full messages, in the context of solving atomic broadcast. We also discuss the implications of executing consensus on message identifiers on the consensus and atomic broadcast algorithms.