Editing DECnet (section)

===1970–1980===
'''Phase I''' (1974)
Support limited to two [[PDP-11]]s running the [[RSX-11]] operating system, or a small number of [[PDP-8]]s running the [[RTS-8]] operating system, with communication over point-to-point ([[DDCMP]]) links between nodes.

'''Phase II''' (1975)<ref>{{cite web |author=Digital Equipment Corporation |date=1978 |url=http://archive.computerhistory.org/resources/text/dec/dec.digital_1957_to_the_present_(1978).1957-1978.102630349.pdf |title=Nineteen Fifty-Seven to the Present |page=53 |publisher=[[Computer History Museum]] |access-date=June 26, 2018 |archive-url=https://web.archive.org/web/20131221052641/http://archive.computerhistory.org/resources/text/dec/dec.digital_1957_to_the_present_(1978).1957-1978.102630349.pdf |archive-date=December 21, 2013 |url-status=dead }}</ref>
Support for networks of up to 32 nodes with multiple, different implementations which could inter-operate with each other. Implementations expanded to include [[RSTS/E|RSTS]], [[TOPS-10]], [[TOPS-20]] and [[VAX/VMS]]<ref>{{cite web |url=https://archive.org/download/bitsavers_decspd25.0_392688/25.03.01_7809_DECnet-VAX_V1.pdf |title=Software Product Description: DECnet-VAX, Version 1 |date=September 1978 |publisher=DEC |access-date=2023-05-23}}</ref> with communications between processors still limited to point-to-point links only.  Introduction of downline loading (MOP), and file transfer using File Access Listener (FAL), remote file access using Data Access Protocol (DAP), task-to-task programming interfaces and network management features.

'''Phase III''' (1980).<ref>{{cite web
   |url=http://www.bitsavers.org/pdf/dec/decnet/AA-AV51A-TK_intrPhIII_May82.pdf
   |title=Introduction to DECnet (Phase III)
   |date=May 22, 1982}}</ref> Support for networks of up to 255 nodes with 8-bit addresses, over point-to point and multi-drop links.  Introduction of adaptive routing capability, record access, a network management architecture, and gateways to other types of networks including IBM's SNA and [[ITU-T|CCITT]] Recommendation [[X.25]].

<div style="background:#f9f9f9;float:right;margin:15px;margin-top:0px;padding:0.2em;border: 1px solid #aaa;font-size:88%">
{| border="0" cellspacing="2" cellpadding="2"
|+ '''DECnet Phase IV protocol suite'''
|----- align="left"
! Application
|  DAP: Data Access Protocol<BR>
CTERM: Command Terminal
|----- align="left"
! Network Management
| NICE: Network Information (and) Control Exchange<br>
MOP: [[Maintenance Operations Protocol]]
|----- align="left"
! Session
| SCP: Session Control Protocol
|----- align="left"
! Transport
| NSP: Network Service Protocol
|----- align="left"
! Network
| DRP: DECnet Routing Protocol
|----- align="left"
! Data link
| DDCMP: Digital Data Communications Message Protocol<br>[[Ethernet]], [[Token Ring]], [[HDLC]], [[Fiber distributed data interface|FDDI]], ...
|----- align="left"
! Physical
| [[Ethernet]], [[Token Ring]], [[Fiber distributed data interface|FDDI]], ...
|}
</div>