Interface Message Processor

<p>The Interface Message Processor (IMP) was the <a href="/facts/Packet_switching/olDlDP1R">packet switching</a>  <a href="/facts/Node_(networking)/LBp2vNcJ">node</a> used to interconnect participant networks to the <a href="/facts/ARPANET/LyMGWurJ">ARPANET</a> from the late 1960s to 1989. It was the first generation of <a href="/facts/Gateway_(telecommunications)/YTYSqhqN">gateways</a>, which are known today as <a href="/facts/Router_(computing)/Nh5cIyVf">routers</a>. An IMP was a <a href="/facts/Rugged_computer/dJv3Gjjr">ruggedized</a> <a href="/facts/Honeywell/qjkujlwJ">Honeywell</a> <a href="/facts/DDP-516/mLXv2hUF">DDP-516</a> <a href="/facts/Minicomputer/g8hvpQxe">minicomputer</a> with special-purpose interfaces and software.  In later years the IMPs were made from the non-ruggedized <a href="/facts/Honeywell_316/mLXv2hUF">Honeywell 316</a> which could handle two-thirds of the communication traffic at approximately one-half the cost. An IMP requires the connection to a host computer via a special bit-<a href="/facts/Serial_communication/r5xP7P1c">serial</a> interface, defined in <i><a href="/facts/BBN_Report_1822/NNUx01pg">BBN Report 1822</a></i>. The IMP software and the ARPA network communications protocol running on the IMPs was discussed in <a href="/facts/RFC_(identifier)/esftTvE7">RFC</a> <a href="https://www.rfc-editor.org/rfc/rfc1">1</a>, the first of a <a href="/facts/Request_for_Comments/esftTvE7">series of standardization documents</a> published by what later became the <a href="/facts/Internet_Engineering_Task_Force/tIcCsFhX">Internet Engineering Task Force</a> (IETF).
</p>

Interface Message Processor open-in-new

Interface Message Processor