ISDN参考结构——把整体结构抽象为许多功能组及区分各组的参考点。ISDN这种表示方法极大的好处是:它使人们可以把网络分别表示成部件的集合,部件间有严格定义的接口。另外,这种参考结构清楚地划分了用户的职能和网络的职能。本文我们主要讨论抽象模式的发展。该模式体现了ISDN通信能力的整体结构概 ISDN Reference Structure - Abstracts the overall structure into many functional groups and distinguishes reference points for each group. The great advantage of this representation of ISDN is that it enables one to represent the network separately as a collection of components with well-defined interfaces between components. In addition, this reference structure clearly distinguishes between user functions and network functions. This article focuses on the development of abstract patterns. This model reflects the overall structure of ISDN communication capabilities