    Network Working Group                                   Alex A. McKenzie
    Request for Comments: 638                                        BBN-NET
    NIC: 30538                                                April 25, 1974

                    IMP/TIP Preventive Maintenance Schedule

          This RFC corrects numerous inaccuracies in RFC #633.  Rather than
          trying to list all the changes, I urge all Liaisons and other
          interested parties to look carefully at the times now listed for
          the sites they are interested in.

       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)

             5 BBN IMP  [0830-1130]

            40 NCC TIP  [1130-1430]

            47 WRIGHT-PATTERSON  [1300-1700]

        First Tuesday

            30 BBN TIP  [0830-1130]

             3 UCSB  [1130-1430]

    McKenzie                                                        [Page 1]

    RFC 638         IMP/TIP Preventive Maintenance Schedule       April 1974

        First Wednesday

            14 CARNEGIE  [0830-1130]

             2 SRI [1200-1500]

        First Thursday

            26 SDAC  [0830-1130]

             4 UTAH  [1030-1330]

            41 NORSAR  [0830-1130]

            42 LONDON  [0830-1130]

        Second Monday

             6 MIT-MAC  [0830-1130]

            44 MIT-IPC  [1200-1500]

            25 DOCB  [1030-1330]

        Second Tuesday

            17 MITRE  [0830-1130]

            23 USC [1130-1430]

        Second Wednesday

            31 CCA  [0830-1130]

            11 STANFORD  [1200-1500]

            32 XEROX  [1400-1700]

            18 RADC [0900-1200]

        Second Thursday

            27 BELVOIR  [0830-1130]

            35 UCSD  [1130-1430]

            37 RML  [0930-1230]

    McKenzie                                                        [Page 2]

    RFC 638         IMP/TIP Preventive Maintenance Schedule       April 1974

        Second Friday

            43 TYMSHARE  [1200-1500]

        Third Monday

             9 HARVARD  [0830-1130]

             1 UCLA  [1000-1300]

            48 KIRTLAND  [1600-1900]

        Third Tuesday

             7 RAND  [1130-1430]

             8 SDC  [1530-1830]

        Third Wednesday

            12 ILLINOIS [0930-1230]

            28 ARPA  [1700-2000]

            15 AMES IMP  [1200-1500]

            16 AMES TIP  [1300-1600]

            36 HAWAII  [1430-1730]

            45 MOFFETT  [1400-1700]

        Third Thursday

            20 ETAC  [0830-1130]

            33 FNWC  [1300-1600]

        Third Friday

            21 LLL  [1230-1530]

        Fourth Monday

            13 CASE  [0830-1130]

    McKenzie                                                        [Page 3]

    RFC 638         IMP/TIP Preventive Maintenance Schedule       April 1974

        Fourth Tuesday

            19 NBS  [0830-1130]

        Fourth Wednesday

            10 LINCOLN  [0830-1130]

            46 RUTGERS  [1000-1400]

        Fourth Thursday

            24 GWC  [1500-1800]

            22 ISI  [1300-1600]

            29 ABERDEEN  [1300-1600]

           [ 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 ]

    McKenzie                                                        [Page 4]