Josh Work U-Michigan MTS Networking History — Merit and UMnet

The Merit Network was launched in 1966 when Michigan State University, Wayne State University, and The University of Michigan established a non-profit corporation known as MERIT to interconnect computers on the three campuses. (MERIT stood for Michigan Education and Research Information Triad, but was changed from an acronym to a word when additional universities joined.) In the years since, Merit has grown to become an important state and national resource for computer communications.

Joining diverse organizations and technologies has always been a Merit strong point. In 1969, when Merit's network designers began to look for data communications equipment to link the three universities, it soon became apparent that no readily available commercial equipment would do the job. Merit solved the problem by designing interfaces for the standard DEC PDP-11 minicomputer. For many years, descendants of the modified machine, called the Primary Communications Processor (PCP), made up the backbone of Merit's statewide network, now known as MichNet.

In 1976, the Hermes software was released to make it possible for users to access Merit directly from interactive terminals. Previously, users had to run a special program from local host computers such as MTS to access the network. When terminal users reached the Hermes system, named after the speedy messenger of the Greek gods, they were asked the familiar question "Which Host?"

In the early 1980s, Merit began to work with the U-M Computing Center to develop U-M's internal network, UMnet. The team built a new computer, the Secondary Communications Processor (SCP), to complement the PCPs.

The SCPs were capable of transmitting data at 19,200 bps, even though most communications software at that time could operate no faster than 9600 bps. The first SCP was deployed in 1983; by the early 1990s, more than 280 were installed around the state.

Another crucial advance was implementation of TCP/IP support in the PCP and SCP technology. MichNet now links virtually every college and university in Michigan to the Internet, along with more than 200 other organizations in fields from government to business to the arts.

The Merit Network not only allowed U-M campus users to collaborate with colleagues at other universities, but also gave them access to countless other networks worldwide. Now one of the nation's leading networking organizations, Merit was the lead partner in building the NSFNET (National Science Foundation Network) Backbone Service from 1987 until 1995. Merit is currently a partner in the U.S. Routing Arbiter project, sponsored by the National Science Foundation.

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This article originally appeared in the May 1996 Information Technology Digest, published by the University of Michigan Information Technology Division. It was written by Susan Topol, ITD Staff Writer, and is copyright © 1996 by the Regents of the University of Michigan.
Last update Jan21/20 by Josh Simon (<>).