Network Host Status
BBN's status report on ARPANET host availability for January 1972.
Westheimer, E., "Network Host Status", RFC 293, DOI 10.17487/RFC0293, January 1972, <https://www.rfc-editor.org/info/rfc293>.
@misc{rfc293,
series = {Request for Comments},
number = 293,
howpublished = {RFC 293},
publisher = {RFC Editor},
doi = {10.17487/RFC0293},
url = {https://www.rfc-editor.org/info/rfc293},
author = {E. Westheimer},
title = {{Network Host Status}},
pagetotal = 4,
year = 1972,
month = jan,
} RFC text
Network Working Group Ellen Westheimer RFC #293 BBN NIC #8303 18 January 1972 Categories: F, G.3 Updates: RFC 288 Obsoletes: None NETWORK HOST STATUS This RFC reports on the status of most Network Hosts from January 3 to January 15. 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. Included here are: Network Address Site Computer ------- ---- -------- 133 BBN PDP-10 (B) 8* SDC IBM-370/155 13 Case PDP-10 15 Ames/(Paoli) ILLIAC-(B6500) 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 and BBN**). This category also includes the Network Control Center 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 The tables on the next two pages summarize the Host status for this period. ______________ *The SDC site is currently replacing their IBM 360/67 by an IBM 370/155. This site therefore is temporarily without any permanent Host on the network, and for this reason was not included in the daily testing for the preceding two weeks. **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. < In the original, the tables on this and the following page were typed > < in "landscape" format. For this online version the tables are > < compressed horizontally to fit on a "portrait"-oriented page > "STATUS OR NETWORK PREDICTION" ADDRESS SITE COMPUTER STATUS OR PREDICTION OBTAINED FROM ------- ---- -------- -------------------- ------------- 1 UCLA SIGMA-7 Server Jon Postel 65 UCLA IBM-360/91 Remote Job Service now, Bob Braden Telnet in April 2 SRI(NIC) PDP-10 Server John Melvin 66 SRI(AI) PDP-10 "Soon" Len Chaiten 3 UCSB IBM-360/75 Server Jim White *5 BBN(NCC) DDP-516 Never Barry Wessler 69 BBN(TENEX-A) PDP-10 Server Alex McKenzie *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 *7 RAND IBM-360/65 User Only Eric Harslem 71 RAND PDP-10 "Soon" Eric Harslem *8 SDC IBM-360/67 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 TX2 Server Will Kantrowitz 11 STANFORD PDP-10 "Soon" Andy Moorer *12 ILLINOIS PDP-11 User Only John Cravits *13 CASE PDP-10 March Charles Rose 14 CARNEGIE PDP-10 "Soon" Hal VanZoeren *15 AMES/(PAOLI) ILLIAC/(B6500) September John McConnell 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 *158 BBN TIP(Prototype) User Only * Host not included in daily testing NET ADDR SITE COMPUTER DATE AND TIME (EASTERN) ---- ---- -------- ----------------------- 1/3 1/4 1/5 1/6 1/7 1/10 1/11 1/12 1/14 1/15 1700 1330 1200 1800 0900 1730 1030 1030 1800 1000 1 UCLA(NMC) SIGMA-7 O O #D O O O O #D O O 65 UCLA(CCN) IBM-360/91 O O O D #D O O O O D 2 SRI(NIC) PDP-10 O #D O O D O O O T O 66 SRI(AI) PDP-10 D D D D D D D D D D 3 UCSB IBM-360/75 D D #D O O D D #D D D 4 UTAH PDP-10 D D #D O O D D #D D D 69 BBN(10X-A)PDP-10 O O H O O O O O D T 6 MIT(Multics)H-645 O D D D O O O D T O 70 MIT(DM) PDP-10 O O O T O O D D O T 71 RAND PDP-10 T D D T D D D D D D 9 HARVARD PDP-10 #T #D O #D D #D O T #D O 10 LL IBM-360/67 D T H D D D H D D H 74 LL TX-2 H H #D T D O H #D O O 11 STANFORD PDP-10 D D D D D D D D D D 14 CARNEGIE PDP-10 D T D D D D D D D H 16 AMES IBM-360/67 D D D D D D D D D H where D = Dead (Destination Host either dead or inaccessible [due to network partitioning or local IMP failure] from the BBN Terminal IMP.) H = 1/2 Open (Destination Host opened a connection but then either immediately closed it, or did not respond any further.) O = Open (Destination Host opened a connection and was accessible to users.) 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 BBN Corp. under the ] [ direction of Alex McKenzie. 12/96 ]
AI ELI5
On this page
§1Introduction
RFC 293 reports on the status of most ARPANET hosts from January 3 to January 15, 1972. Ellen Westheimer at BBN continued the biweekly reporting practice established in RFC 235, gathering status information from site operators and conducting daily automated tests.
The testing captured a snapshot of network availability in early 1972, when the ARPANET had about 15 operational sites and many hosts were still under development or transitioning to new hardware.
BBN checked every few days to see which computers were working and ready for visitors on the network during these two weeks in January.
§2Host Categories and Status Codes
Hosts fell into several categories. Some were not expected to be network servers for at least two weeks (like CASE and Ames), and therefore were not included in daily testing. Others were user-only sites or Terminal IMPs (like the Network Control Center at address 5).
The RFC uses status codes for each login test: O for open and accessible, D for dead or inaccessible, T for timed out, H for half-open (connected but then closed), and R for refused. The tables show daily test results across the period.
Some computers weren't being tested because they weren't ready yet. For those that were tested, the codes showed: O for working, D for dead, T for too slow, H for half-working, and R for refusing the connection.
§3Status Data
The RFC includes tables showing which computers were servers, user-only, or under development, plus daily test results from nine different dates spanning January 3-15. The data reveals the unreliability of early networking: hosts frequently timed out, became inaccessible, or only half-opened connections.
Notably, UCLA's SIGMA-7 and IBM-360/91, SRI's NIC PDP-10, and BBN's PDP-10 showed relatively good availability, while others like Stanford's PDP-10 and Case's PDP-10 had poor connectivity during this period.
The tables show which computers worked on different days. Some were reliable, but many would stop answering calls from time to time.