A communication device is described that comprises a first data unit buffer for holding data units of a first communication protocol and a second data unit buffer for holding data units of a second communication protocol. The first communication protocol is a communication protocol suitable for transmitting data units from a sending peer of the first communication protocol to a receiving peer of the first communication protocol over one or more relay peers of the first communication protocol. The first communication protocol provides for at least a first type (RACK) of receipt information that is indicative of a correct receipt at a relay peer and a second type (ACK) of receipt information that is indicative of a correct receipt at the receiving peer. The second communication protocol can be a conventional ARQ protocol or a protocol using the two types of receipt information.