In SNA, a type of session between two LU-LU half-sessions using SNA-defined protocols for transmission control and data flow control, but using end-user or product-defined protocols to augment or replace FMD services protocols; for example, a session that involves an application program using IMS/VS and an IBM4700 Finance Communication System, in which the operator of the 4700 terminal is updating the passbook balance for a customer's savings account.; 在IBM系統(tǒng)網(wǎng)絡(luò)體系結(jié)構(gòu)(SNA)中,兩個LU-LU話路端之間的一種話路類型。該話路類型 使用SNA定義的協(xié)議進(jìn)行傳輸控制和數(shù)據(jù)流控制,而且使用端點用戶協(xié)議或產(chǎn)品定義的協(xié)議來擴(kuò)充或替代FMD服務(wù)協(xié) 議。例如,在一個使用IMS/VS的應(yīng)用程序和IBM 4700金融通信系統(tǒng)的話路中,4700終端操作員 對客戶存款帳號的銀行存款結(jié)余進(jìn)行修改。