Editing Systems Network Architecture (section)

==Competitors==
The proprietary networking architecture for [[Honeywell Bull]] mainframes is [[Distributed Systems Architecture]] (DSA).<ref>{{cite web |title=Distributed Systems Architecture |url=http://www.feb-patrimoine.com/english/distributed_systems_arch.htm}}</ref> The Communications package for DSA is [[VIP terminal|VIP]]. DSA is also no longer supported for client access. Bull mainframes are fitted with [[Mainway]] for translating DSA to [[TCP/IP]] and VIP devices are replaced by TNVIP [[Terminal Emulations]] ([[GLink]], [[Winsurf]]). [[General Comprehensive Operating System|GCOS 8]] supports [[TNVIP SE]] over TCP/IP.

The networking architecture for [[Univac]] mainframes was the Distributed Computing Architecture (DCA), and the networking architecture for [[Burroughs Corporation|Burroughs]] mainframes was the Burroughs Network Architecture (BNA); after they merged to form [[Unisys]], both were provided by the merged company. Both were largely obsolete by 2012. [[International Computers Limited]] (ICL) provided its Information Processing Architecture (IPA).

[[DECnet]]<ref>{{cite magazine |magazine=[[Hardcopy (magazine) |Hardcopy]] |pages=62–65 |title=Giving DECnet a LAN |author1=James M. Moran |author2=Brian J. Edwards |date=February 1984}}</ref><ref>{{cite web |title=DECnet for Linux |publisher=[[SourceForge]] |url=http://sourceforge.net/apps/mediawiki/linux-decnet/index.php?title=Main_Page |access-date=June 26, 2018 |url-status=dead |archive-url=https://web.archive.org/web/20091004142729/http://sourceforge.net/apps/mediawiki/linux-decnet/index.php?title=Main_Page |archive-date=October 4, 2009}}</ref><ref>{{cite news |newspaper=[[The New York Times]] |title=Networking Products Introduced by Digital |date=August 24, 1988 |url=https://www.nytimes.com/1988/08/24/business/company-news-networking-products-introduced-by-digital.html}}</ref> is a suite of [[network protocol]]s created by [[Digital Equipment Corporation]], originally released in 1975 to connect two [[PDP-11]] [[minicomputers]]. It evolved into one of the first [[peer-to-peer]] network architectures, thus transforming DEC into a networking powerhouse in the 1980s.

SNA also competed with [[ISO]]'s [[Open Systems Interconnection]], which was an attempt to create a vendor-neutral network architecture that failed due to the problems of "[[design by committee]]".{{cn|date=January 2024}} OSI systems are very complex, and the many parties involved required extensive flexibilities that hurt the interoperability of OSI systems, which was the prime objective to start with.{{cn|date=January 2024}}

The TCP/IP suite for many years was not considered a serious alternative by IBM, due in part to the lack of control over the intellectual property.{{Citation needed|date=January 2019}} The 1988 publication of {{IETF RFC|1041}}, authored by [[Yakov Rekhter]], which defines an option to run [[IBM 3270]] sessions over [[Telnet]], explicitly recognizes the customer demand for interoperability in the data center. Subsequently, the IETF expanded on this work with multiple other RFCs. [[tn3270|TN3270]] (Telnet 3270), defined by those RFCs, supports direct client-server connections to the mainframe using a TN3270 server on the mainframe, and a TN3270 emulation package on the computer at the end user site. This protocol allows existing VTAM applications (CICS, TSO) to run with little or no change from traditional SNA by supporting traditional 3270 terminal protocol over the TCP/IP session. This protocol is widely used to replace legacy SNA connectivity more than [[Data-Link Switching]] (DLSw) and other SNA replacement technologies. A similar [[tn5250|TN5250]] (Telnet 5250) variant exists for the [[IBM 5250]].