Specifies the default minimum retransmission time out (RTO) value. The calculated RTO for all TCP connections cannot be lower than this value. See also tcp_rexmit_interval_max.
1 millisecond to 20 seconds
Do not change the value in a normal network environment.
TCP's RTO calculation should cope with most RTT fluctuations. If, in some very special circumstances, the round-trip time (RTT) for a connection is about 10 seconds, increase this value. If you change this value, you should change the tcp_rexmit_interval_max parameter. Change the value of tcp_rexmit_interval_max to at least eight times the value of tcp_rexmit_interval_min.