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RFC 590 UNKNOWN INFRASTRUCTURE · ADMINISTRATIVE

MULTICS address change

MIT-Multics moves to a new network address to balance load

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PUBLISHED
November 1973
AUTHORS
M.A. Padlipsky
STREAM
Legacy
OLD ADDRESS
6 (decimal)
NEW ADDRESS
44 (decimal)
CHANGEOVER DATE
Monday, December 17, 1973
DISTANCE TO NEW IMP
~2000 feet from old location
DOI
10.17487/RFC0590

RFC text

Original text · RFC Editor View on rfc-editor.org ↗ 
Network Working Group                                       M. Padlipsky
Request for Comments: 590                                    MIT-Multics
NIC: 20326                                              19 November 1973


                         Multics Address Change

   We will be changing the Network address of MIT-Multics from 6 to 44
   (decimal) on Monday, December 17, 1973.  Please make any necessary
   table and program changes then, and accept our apologies for the
   inconvenience.

   The change was necessitated by the fact that 1) there were some nine
   uses for the four ports on IMP 6, making the second MIT IMP
   desirable; 2) there were four very active Hosts on IMP 6, making the
   shift of at least one of them to the new, less busy IMP desirable;
   and 3) the new Multics machine is some 2000 feet from the old IMP,
   making it the logical candidate for the move.

   It is likely that we will have one or two additional test sessions on
   the new IMP prior to the changeover date.  These will be announced in
   our "message of the day", and would only affect -- temporarily --
   users who cannot employ numeric Host addresses directly.


   RECEIVED AT NIC 11-21-73


         [ This RFC was put into machine readable form for entry ]
          [ into the online RFC archives by Lorrie Shiota 1/02 ]

AI ELI5

On this page
PROBLEMThe IMP serving MIT (Interface Message Processor number 6) was overloaded, with nine uses for its four available ports and four very active hosts trying to use it.
MECHANISMMIT-Multics, one of the active hosts on IMP 6, was moved to a new IMP (number 44) on December 17, 1973. This required all network users and sites to update their host tables and programs with the new network address.
THE MOVEThe load was distributed more evenly across the IMPs. MIT-Multics became reachable at address 44 instead of address 6.

§1Address Change Announcement

MIT-Multics, an important host on the ARPANET, is changing its network address from 6 to 44 (decimal) on Monday, December 17, 1973. All sites that have the MIT-Multics address in their host tables, network code, or programs must update these entries before the changeover date.

The author, M. Padlipsky, asks for the network's patience during the transition and apologizes for the inconvenience.

An important computer at MIT is moving to a new address on the network, and everyone needs to update their lists.

§2Reasons for the Move

The change was made necessary by three factors. First, IMP 6 was overloaded: there were nine different network services needing its four available ports, making the addition of a second MIT IMP desirable. Second, IMP 6 had four very active hosts, and moving at least one of them to the new, less busy IMP would improve performance and availability. Third, the new Multics machine is located about 2000 feet from the old IMP, while the new Multics location is much closer to the new (less busy) IMP.

The old network connection point at MIT was crowded and had too many computers on it, so the Multics computer moved to a new, less busy connection point.

§3Transition Plan and Testing

It is likely that one or two additional test sessions will be run on the new IMP prior to the changeover date of December 17. These test sessions will be announced in the MIT-Multics "message of the day" and would temporarily affect only users who are unable to employ numeric host addresses directly (i.e., users who rely on looking up the address by name rather than knowing the numeric address to enter directly).

Users who use numeric addresses in their code and can easily change them should prepare to make those changes on the changeover date. Sites that rely on name services should check that their name service is updated.

Before the big move, there will be some test runs so problems can be found early. On December 17, the address will officially change, and anyone who looks up the address by name will still be fine, but anyone with the address hardcoded in their programs will need to update.