IMP/TIP preventive maintenance schedule
A monthly schedule of network equipment maintenance times.
McKenzie, A.M., "IMP/TIP preventive maintenance schedule", RFC 445, DOI 10.17487/RFC0445, January 1973, <https://www.rfc-editor.org/info/rfc445>.
@misc{rfc445,
series = {Request for Comments},
number = 445,
howpublished = {RFC 445},
publisher = {RFC Editor},
doi = {10.17487/RFC0445},
url = {https://www.rfc-editor.org/info/rfc445},
author = {A.M. McKenzie},
title = {{IMP/TIP preventive maintenance schedule}},
pagetotal = 2,
year = 1973,
month = jan,
} RFC text
Network Working Group Alexander A. McKenzie
RFC # 445 BBN-NET
NIC # 14028 January 22, 1973
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 such
rescheduling occurs, we will announce the fact as soon as possible via
two mechanisms - the TIP NEWS and a Journal note (NOT an RFC) to
Technical Liaisons. Any permanent changes to the schedule will be
announced via the RFC mechanism.
All times show below are Eastern Time.
First Monday (of each month)
BBN IMP [0830-1130]
First Tuesday
BBN TIP [0830-1130]
UCSB [1130-1430]
First Wednesday
CARNEGIE [0830-1130]
SRI [1130-1430]
XEROX [1500-1800]
First Thursday
SAAC [0830-1130]
UTAH [1030-1330]
Second Monday
MIT [0830-1130]
NOAA [1030-1330]
Second Tuesday
MITRE [0830-1130]
USC [1130-1430]
Second Wednesday
CCA [0830-1130]
STANFORD [1130-1430]
RADC [1430-1730]
Second Thursday
BELVOIR [0830-1130]
UCSD [1130-1430]
PATRICK [0930-1230]
Third Monday
HARVARD [0830-1130]
UCLA [1000-1300]
Third Tuesday
RAND [1130-1430]
SDC [1530-1830]
Third Wednesday
ILLINOIS [0930-1230]
ARPA [0830-1130]
AMES IMP [1130-1430]
Third Thursday
ETAC [0830-1130]
FNWC [1130-1430]
Fourth Monday
CASE [0830-1130]
HAWAII [1330-1630]
Fourth Tuesday
NBS [0830-1130]
LBL [1130-1430]
Fourth Wednesday
LINCOLN [0830-1130]
AMES TIP [1130-1430]
Fourth Thursday
GWC [0930-1230]
ISI [1300-1600]
ABERDEEN [0830-1130]
[ 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. 9/99 ]
AI ELI5
On this page
§1The Maintenance Schedule
RFC 445 publishes the preventive maintenance schedule for the ARPANET's IMPs (Interface Message Processors, the network routers) and TIPs (Terminal Interface Processors, which let terminals join the network). Maintenance is scheduled monthly, and each machine is normally serviced at the same time each month.
Wherever possible, the maintenance time is chosen to coincide with the scheduled maintenance of the hosts at the same site, so that disruption to users is minimized.
Each network box gets fixed once a month at a time that the people running it already expect to be offline.
§2Announcing Changes
Occasional rescheduling is necessary due to network connectivity issues or other operational concerns. The RFC explains that temporary rescheduling would be announced via two mechanisms: the TIP NEWS and a Journal note to Technical Liaisons. Any permanent changes to the schedule would be announced via RFC.
If the date changes, network managers announce it through newsletters and official messages.
§3The Time Slots
The schedule lists maintenance windows for all sites, grouped by week and day of the month. For example, the first Monday of each month shows BBN IMP's maintenance slot, from 08:30 to 11:30 Eastern Time. Each site has a specific day and time, and where multiple machines are at one location, their maintenance is staggered throughout the month to avoid simultaneous outages.
The schedule says which machines get fixed on which days and what time they will be down.