一、概述七十年代中期以来,国外一些计算机厂家纷纷提出了自己的计算机网络体系。1974年9月,IBM公司首先发表了“系统网络体系”(SNA)。紧接着,数字设备公司(DEC)于1975年3月发表了“数字网络体系”(DNA)。此后,UNIVAG公司宣布了“分布式计算机体系”(DCA),BURROUGHS公司也有自己的统一体系“分布式数据处理网络系统”(DNS)。在日本,近年来各公司相继发表的计算机网络体系有:“富士通网络体系”(FNA),日电的“分布式信息处理网络体系”(DINA),东芝的“先进网络系统体系”(ANSA),三菱电气的“三菱网络体系”(MNA),冲电气的“分布的开放式网 First, an overview Since the mid-seventies, some foreign computer manufacturers have put forward their own computer network system. September 1974, IBM first published ”System Network System “ (SNA). Then, Digital Equipment Corporation (DEC) published ”Digital Network System“ (DNA) in March 1975. Since then, UNIVAG has announced its ”Distributed Computer System“ (DCA), and BURROUGHS also has its own unified system, ”Distributed Data Processing Network System“ (DNS). In Japan, in recent years, various computer network systems published successively by various companies include: ”Fujitsu Network System“ (FNA), NEC’s ”Distributed Information Processing Network System“ (DINA), Toshiba’s Advanced Network System System ”(ANSA), Mitsubishi Electric’s“ Mitsubishi Network System ”(MNA), OKI’s open distribution network