An enhancement to the MNP family of modem protocols, MNP 4 added variable packet assembly, which adjusts the packet size downward to compensate for line conditions that cause dropped packets. (Note: MNP supports packets as small as 64 bytes and as large as 256 bytes.) Reducing the packet size reduces the raw packet efficiency, as the ratio of payload to overhead drops, but increases throughput under such conditions, as smaller packets are more likely to transit the connection without error and, therefore, unlikely to require retransmission. See also byte, MNP, modem, overhead, packet, payload, protocol, and throughput.