The SYN/ACK speedup method is used to accelerate IP data traffic. With SYN/ACK speedup IP check characters (SYN for synchronization and ACK for acknowledge) a given preference within the transmission buffer over simple data packets. This prevents the situation that check characters remain in the transmission queue for a longer time and the remote station stop sending data as a result.
The greatest effect occurs with SYN/ACK speedup with fast connections (e. g. ADSL) when data quantities are simultaneously transferred in both directions at high speed.
The SYN/ACK speedup is activated at the factory.