Delayed ACK

Delayed ACK delays the receipt acknowledgement (ACK) of a TCP packet by up to 200ms. This delay increases the chance that the ACK can be sent along with the response to the received packet, reducing network traffic. However, if the sender is waiting for the ACK before sending a new packet (for example, due to implementation of Nagle’s algorithm), and there is no response to the packet just sent (for example, because it is part of a file transfer), communication is unnecessary delayed.

z/OS® Explorer allows you to disable the delayed ACK function. On the host, this is done with the DSTORE_TCP_NO_DELAY directive in rse.env, as documented in the Host Configuration Guide (SC27-8437).