A first user equipment can communicate with a second user equipment in a direct mode or in an infrastructure mode via a base station of a network. To communicate with the second user equipment, the first user equipment generates packets and forwards the packets to a lower protocol layer of a protocol stack. The first user equipment also acts as a buffer protocol entity by storing the packets until acknowledgement of receipt is received from the second user equipment. If the first user equipment switches from the direct mode to the infrastructure mode, or vice versa, the first user equipment forwards each of the stored packets to the lower protocol layer for transmission to the second user equipment using the current mode.