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RFC 633 UNKNOWN INFRASTRUCTURE · MAINTENANCE

IMP/TIP preventive maintenance schedule

Schedule of preventive maintenance windows for all IMP and TIP machines.

On rfc-editor.org ↗
PUBLISHED
March 1974
AUTHORS
A.M. McKenzie
STREAM
Legacy
OBSOLETED BY
RFC 638 — IMP/TIP preventive maintenance schedule
MAINTENANCE FREQUENCY
Monthly
RESERVED MAINTENANCE WINDOW
Tuesday 7-9 am Eastern Time
SCHEDULE UNIT
Week of month (first through fourth)
DOI
10.17487/RFC0633
LINEAGE · FROM THE RFC INDEXOpen full graph →
'74RFC 633IMP/TIP preventive maintenance schedule'74RFC 638IMP/TIP preventive maintenance schedule

RFC text

Original text · RFC Editor View on rfc-editor.org ↗ 
Network Working Group                                        A. McKenzie
Request for Comments: 633                                        BBN-NET
NIC: 30240                                                March 18, 1974


                  IMP/TIP Preventive Maintenance Schedule

   This note presents the current IMP/TIP Preventive Maintenance
   schedule.  Preventive Maintenance is scheduled on a monthly basis and
   a given machine is normally scheduled at the same time each month;
   wherever possible the time is chosen to coincide with the PM time for
   the Host(s) at the site.

   It is sometimes necessary to reschedule PM's because of network
   connectivity considerations or for other reasons.  Whenever this is
   necessary we will follow the usual procedure for scheduling down time
   with our "primary contact" at the site.  Permanent changes to the
   schedule will he announced via the RFC mechanism.

   PM's normally do not require the IMP/TIP to be taken down.  However,
   machines must be taken down in some cases, so no one should rely on
   the machine remaining available through the PM period.

   PLEASE REMEMBER THAT TUESDAY MORNINGS FROM 7am TO 9am ARE RESERVED
   FOR NETWORK SOFTWARE MAINTENANCE.


   All times shown below are Eastern Time.

    First Monday (of each month)

        BBN IMP  [0830-1130]

        NCC TIP  [1130-1430]

        WRIGHT-PATTERSON  [1300-1700]

    First Tuesday

        BBN TIP  [0830-1130]

        UCSB  [1130-1430]

    First Wednesday

        CARNEGIE  [0830-1130]

        SRI [1130-1430]

    First Thursday

        SDAC  [0830-1130]

        UTAH  [1030-1330]

        NORSAR  [0830-1130]

        LONDON  [0830-1130]

    Second Monday

        MIT-MAC  [0830-1130]

        MIT-IPC  [1200-1500]

        DOCB  [1030-1330]

    Second Tuesday

        MITRE  [0830-1130]

        USC [1130-1430]

    Second Wednesday

        CCA  [0830-1130]

        STANFORD  [1130-1430]

        XEROX  [1500-1800]

        RADC [1430-1730]

    Second Thursday

        BELVOIR  [0830-1130]

        UCSD  [1130-1430]

        RML  [0930-1230]

    Second Friday

        TYMSHARE  [1300-1600]

    Third Monday

        HARVARD  [0830-1130]

        UCLA  [1000-1300]

        KIRTLAND  [1600-1900]

    Third Tuesday

        RAND  [1130-1430]

        SDC  [1530-1830]

    Third Wednesday

        ILLINOIS [0930-1230]

        ARPA  [1800-2100]

        AMES IMP  [1130-1430]

        AMES TIP  [0800-1130]

        HAWAII  [1130-1430]

        MOFFETT  [1500-1600]

    Third Thursday

        ETAC  [0830-1130]

        FNWC  [1130-1430]

    Fourth Monday

        CASE  [0830-1130]

    Fourth Tuesday

        NBS  [0830-1130]

        LBL  [1130-1430]

    Fourth Wednesday

        LINCOLN  [0830-1130]

        RUTGERS  [1000-1400]

    Fourth Thursday

        GWC  [0930-1230]

        ISI  [1300-1600]

        ABERDEEN  [0830-1130]

    Fourth Friday

        LLL  [1330-1730]











       [ This RFC was put into machine readable form for entry ]
       [ into the online RFC archives by Alex McKenzie with    ]
       [ support from GTE, formerly BBN Corp.           2/2000 ]

AI ELI5

On this page
PROBLEMARPANET users needed to know when each site's packet-switching machine would be unavailable for regular maintenance.
MECHANISMRFC 633 publishes a monthly schedule of preventive maintenance (PM) times for every IMP and TIP on the network, grouped by week of the month and listed with the site name and the Eastern Time window.
OPERATIONAL REFERENCEThe schedule lets users and system operators plan around known downtime, though the RFC notes that unexpected rescheduling may be necessary.

§1Introduction

RFC 633 presents the preventive maintenance schedule for every IMP (Interface Message Processor) and TIP (Terminal Interface Processor) on ARPANET. Preventive maintenance is scheduled monthly, with each machine assigned a consistent time of the month. Where possible, the PM window aligns with the host's own maintenance time to minimize disruption.

All the packet routers get monthly check-ups. Each one has its own day and time.

§2The Schedule

The schedule is organized by week of month (first through fourth) and then by day (Monday through Friday). Each entry lists the site name and the maintenance window in Eastern Time (e.g., "BBN IMP [0830-1130]"). Most PMs do not require the machine to be down, but users should not rely on the machine remaining available during the PM period. Tuesday mornings from 7 to 9 am are always reserved for network-wide software maintenance.

The schedule says which day each machine gets serviced and from when to when, in Eastern Time. Don't count on the network working during these windows.

§3Rescheduling and Contingencies

The RFC notes that PM scheduling sometimes must change due to network connectivity considerations or other reasons. When rescheduling is necessary, BBN follows the usual procedure for scheduling downtime with the site's primary contact. Permanent changes to the schedule are announced via RFC.

If the schedule needs to change, BBN calls the site first and posts an updated schedule.