In SNA, the LU-LU half-session defined at session activation as having to request and receive permission from the other LU-LU half-session to start a bracket.

• 系统网络体系结构(SNA)中,在话路激活时定义的一种LU-LU部分话路,它必须在发出请求并且收到该LU-LU部分话路的另一端的允许之后,才能开始一次按类通信。