Network host status
Checking which network hosts were working in late May and early June 1972
Westheimer, E., "Network host status", RFC 353, DOI 10.17487/RFC0353, June 1972, <https://www.rfc-editor.org/info/rfc353>.
@misc{rfc353,
series = {Request for Comments},
number = 353,
howpublished = {RFC 353},
publisher = {RFC Editor},
doi = {10.17487/RFC0353},
url = {https://www.rfc-editor.org/info/rfc353},
author = {E. Westheimer},
title = {{Network host status}},
pagetotal = 5,
year = 1972,
month = jun,
} RFC text
Network Working Group Ellen Westheimer
Request for Comments: 353 BBN
NIC #10595 12 June 1972
Categories: F, G.3
Updates: RFC #344
Obsoletes: None
NETWORK HOST STATUS
This RFC reports on the status of most Network Hosts from May 22 to
June 2.
No testing was done on Memorial Day, which Massachusetts celebrated
on May 29. No testing was done on May 31 and June 1 due to an
attempt to install the new IMP system.
Three new terminal IMPs were installed during this interval. On June
1, Terminal IMP #155 was installed at Fort Belvoir in Fairfax,
Virginia; on June 3, Terminal IMP #154 was installed at SAAC (Seismic
Array Analysis Center) in Alexandria, Virginia; and on June 5,
Terminal IMP #153 was installed at NOAA (National Oceanic Analysis
Agency) in Boulder, Colorado.
Several Hosts are currently excluded from the daily testing. These
Hosts fall into two categories:
1) Hosts which are not expected to be functioning on the Network as
servers (available for use from other sites) on a regular basis
for at least two weeks. The only Host in this category is the
PDP-10 at Case (Network address 13).
2) Hosts which are currently intended to be users only. Included
here are the Terminal IMPs, which are presently in the Network
(AMES, MITRE, NBS, ETAC, USC, GWC, NOAA, SAAC, BELVOIR, and
BBN*). This category also includes the Network Control Center
___________
*The BBN Terminal IMP (Network Address 158) is a prototype and as
such is frequently not connected to the Network, but being used
to refine and debug the Terminal IMP programs.
computer (Network address 5) which is used solely for gathering
statistics from the Network. Finally, included among these Hosts are
the following:
Network
Address Site Computer
------- ---- --------
7 Rand IBM-360/65
73 Harvard PDP-1
12 Illinois PDP-11
19 NBS PDP-11
23 USC IBM-360/44
The tables on the next two pages summarize the Host status for this
period.
STATUS OR
SITE PREDICTIONS
ADDRESS SITE COMPUTER STATUS OR PREDICTION OBTAINED FROM
1 UCLA SIGMA-7 Server #Limited Jon Postel
65 UCLA IBM-360/91 NETRJS now Bob Braden
(Telnet in June)
2 SRI (NIC) PDP-10 Server Jim White
66 SRI (AI) PDP-10 Server Len Chaiten
3 UCSB IBM-360/75 Server Ron Stoughton
4 UTAH PDP-10 Server Barry Wessler
*5 BBN (NCC) DDP-516 Never Alex McKenzie
69 BBN (TENEX-A) PDP-10 Server Dan Murphy
133 BBN (TENEX-B) PDP-10 Server (Exper.) Dan Murphy
6 MIT (Multics) H-645 Server Mike Padlipsky
70 MIT (DM) PDP-10 Server Bob Bressler
134 MIT (AI) PDP-10 Server Jeff Rubin
*7 RAND IBM-360/65 User Only Eric Harslem
71 RAND PDP-10 Server Eric Harslem
8 SDC IBM-370/155 Server Bob Long
9 HARVARD PDP-10 Server Bob Sundberg
*73 HARVARD PDP-1 User Only Bob Sundberg
10 LINCOLN IBM-360/67 "Soon" Joel Winett
74 LINCOLN TX-2 Server Will Kantrowitz
11 STANFORD PDP-10 Server Andy Moorer
*12 ILLINOIS PDP-11 User Only John Cravitz
*13 CASE PDP-10 June Charles Rose
14 CARNEGIE PDP-10 Server Hal VanZoeren
15 AMES ILLIAC Server John McConnell
(B6500)
16 AMES IBM-360/67 "Soon" Wayne Hathaway
*144 AMES TIP User Only
*145 MITRE TIP User Only
*19 NBS PDP-11 User Only Robert Rosenthal
*147 NBS TIP User Only
*148 ETAC TIP User Only
*23 USC IBM-360/44 User Now James Pepin
*151 USC TIP User Only
*152 GWC TIP User Only
*153 NOAA TIP User Only
*154 SAAC TIP User Only
*155 BELVOIR TIP User Only
*158 BBN TIP User Only
(Prototype)
_________
*Host not included in daily testing
#The NMC is a research site and would like to have prior arrangement
with each user.
NO. SITE DATE AND TIME (EASTERN)
--- ---- 5/22 5/23 5/24 5/25 5/26 5/30 6/2
1700 1800 1300 1300 1600 1430 1300
1 UCLA-NMC O O T D D O D
65 UCLA-CCN* O O O O D O D
2 SRI-ARC O O O O O O O
66 SRI-AI O D O D D D D
3 UCSB-MOD75 O O D O O O O
4 UTAH-10 O O O O O D D
69 BBN-TENEX D O O O O O O
133 BBN-TENEXB O O O O #T O #D
6 MIT-MULTICS D O O O O O O
70 MIT-DMCG O H O O O O O
134 MIT-AI D T D D T H H
71 RAND-CSG D D D D O D O
8 SDC-ADEPT H D #D #D H #D #D
9 HARVARD-10 O O O O O O O
10 L.L.-360 D D D H H H H
74 L.L.-TX-2 O O #D D D O O
11 STANFORD-AI O O O H O D D
14 CMU-10 D O D O O O O
15 AMES-ILLIAC T T T T T T T
16 AMES-67 D T D D D D D
where
D = Dead (Destination Host either dead or inaccessible [due to
network partitioning or local IMP failure] from the BBN Terminal
IMP.)
F = Full (Destination Host opened a connection, informed user that
all Network ports were in use, and immediately closed the
connection.)
H = 1/2 Open (Destination Host opened a connection but then either
immediately closed it, or did not respond any further.)
O = Open (Destination opened a connection and was accessible to us.
R = Refused (Destination Host returned a CLS to the initial RFC.)
T = Timed out (Destination Host did not complete the ICP and open a
connection within 60 seconds.)
__________
*The only service currently offered by the UCLA IBM-360/91 is a Network
Job Service (NETRJS), however, the BBN Terminal IMP is not equipped to
test NETRJS. We are assuming that initial connection to the NETRJS
logger indicates that NETRJS is also functioning.
#These sites advertise that they may not have their system available at
these times.
[ This RFC was put into machine readable form for entry ]
[ into the online RFC archives by Bob German 10/99 ]
AI ELI5
On this page
§1Introduction
RFC 353 reports on host status from May 22 to June 2, 1972. During this period, three new Terminal IMPs were installed: Terminal IMP #155 at Fort Belvoir in Virginia (June 1), Terminal IMP #154 at SAAC (Seismic Array Analysis Center) in Alexandria, Virginia (June 3), and Terminal IMP #153 at NOAA (National Oceanic and Atmospheric Administration) in Boulder, Colorado (June 5). No testing was done on May 29 (Memorial Day) or May 31 and June 1 (due to an attempt to install the new IMP system).
Three new locations got Terminal IMPs, which let more organizations connect to the network. The ARPANET team was also working on upgrading the main switching equipment.
§2Host Categories
By June 1972, the excluded category included Terminal IMPs (now at AMES, MITRE, NBS, ETAC, USC, GWC, NOAA, SAAC, BELVOIR, and BBN) and the Network Control Center (Address 5). The only non-server host excluded was the PDP-10 at Case (Address 13), still expected to become a server.
The operational servers remained the major universities and research centers: UCLA, SRI, UCSB, UTAH, MIT (three sites), RAND, SDC, Harvard, Lincoln, Stanford, Carnegie, and AMES, forming the backbone of the early ARPANET.
New Terminal IMPs let smaller offices and agencies connect to the network without their own big computer. Most of the big research computers were already set up to share.
§3Status Patterns
The testing results show varying reliability across the network. Some machines like SRI-NIC, UCSB, MIT-Multics, and Harvard were consistently Open. Others like SRI-AI remained dead throughout the period. Some hosts like AMES-67 were dead every single day, indicating systematic failures that persisted across several months.
The network showed the typical challenges of early distributed computing: intermittent connectivity issues, regularly scheduled downtime for system work, and varying implementation maturity across different host sites.
Some computers worked reliably every day. Others were broken almost all the time. Some were sometimes up and sometimes down. Building a network across many different computers was hard.