BSD sockets setsockopt option to avoid waiting for acknowledge before next send

Question

I am trying to send some KBytes of data trough Ethernet with a proprietary simple raw TCP protocol.

Standard Windows configuration requires two (2) packets received before returning an acknowledge packet, unless you modify the registry with TcpAckFrequency = 1, in which case one received packet is enough to send back the acknowledgement, or otherwise anyway you will get an ACK after TcpDelAckTicks * 100 = 200 ms by default (this is another registry key). This is a problem if I send the data in chunks of less than 1460 bytes, because each chunk will get an acknowledge after 200 ms, and the sender will wait that before sending the next packet. One solution is to send data in pieces bigger than 1460 bytes, so that two packets will be actually sent and ACK received.

But, what about if I want to send smaller packets? Is there a way to configure the socket with setsockopt for not waiting acknowledgment packets before sending the next packet?

Thank you very much in advance.

Answer 1

Turn off the Nagle algorithm at the sender. In C this is the TCP_NODELAY option.