In Systems Network Architecture (SNA), an operational mode in which the sender stops sending request units on a given flow (normal or expedited) after sending a definite-response request chain on that flow until a response is made to the chain.

• 系统网络体系结构(SNA)中的一种工作方式,在此方式下,发送端在给定的信息流(正常流或加急流)上发送出一个确定应答请求链之后,就停止在该信息流上发送请求单元,直到这个链被响应。