Network Host Status
A weekly health check of ARPANET hosts, with a table of which ones answered a test connection.
Westheimer, E., "Network Host Status", RFC 376, DOI 10.17487/RFC0376, August 1972, <https://www.rfc-editor.org/info/rfc376>.
@misc{rfc376,
series = {Request for Comments},
number = 376,
howpublished = {RFC 376},
publisher = {RFC Editor},
doi = {10.17487/RFC0376},
url = {https://www.rfc-editor.org/info/rfc376},
author = {E. Westheimer},
title = {{Network Host Status}},
pagetotal = 5,
year = 1972,
month = aug,
} RFC text
Network Working Group Ellen Westheimer
NIC # 11118 BBN
RFC # 376 8 August 1972
Categories: F, G.3
Updates: RFC #370
Obsoletes: None
NETWORK HOST STATUS
This RFC reports on the status of most Network Hosts from
July 31 to August 4.
Several Hosts are currently excluded from the daily testing
as they are presently intended to be users only. Included here
are the Terminal IMPs, which are presently in the Network (AMES,
MITRE, RADC, NBS, ETAC, USC, GWC, NOAA, SAAC, ARPA, 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
138 Lincoln TSP
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.
NOTE: Ellen Westheimer left BBN to return to school on August 4.
We therefore will discontinue the publication of these summaries.
It is my understanding that UCLA-NMC is considering the publica-
tion of similar, although more detailed, survey data in the near
future; I hope that data will serve in lieu of these reports. In
addition, of course, MIT-DMCG has had survey information available
on line for some time (see RFC #308, NIC 9259.)
- Alex McKenzie -
_______________
*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.
STATUS OR
PREDICTIONS
ADDRESS SITE COMPUTER STATUS OR PREDICTION OBTAINED FROM
------- ---- -------- -------------------- -------------
1 UCLA SIGMA-7 Sever #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
198 MIT (ML) 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
*138 LINCOLN TSP User Only Tom Barkelow
11 STANFORD PDP-10 Server Andy Moorer
12 ILLINOIS PDP-11 User Only John Cravits
13 CASE PDP-10 July Charles Rose
14 CARNEGIE PDP-10 Server Hal VanZoeren
15 AMES ILLIAC Server John McConnell
(PDP-10)
16 AMES IBM-360/67 "Soon" Wayne Hathaway
*144 AMES TIP User Only
*145 MITRE TIP User Only
*146 RADC 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
*156 ARPA 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 a prior arrangement with each user.
NO. SITE DATE AND TIME (EASTERN)
--- ---- -----------------------
7/31 8/1 8/2 8/3 8/4
1400 1830 1330 1500 1330
1 UCLA-NMC H O O O O
65 UCLA-CNN* O O O O O
2 SRI-ARC O O O O O
66 SRI-AI D D O T O
3 UCSB-MOD75 O O O O O
4 UTAH-10 O O O O O
69 BBN-TENEX O T T O R
133 BBN-TENEXB #D #T #T #T #D
6 MIT-MULTICS O T O O O
70 MIT-DMCG O H O O O
134 MIT-AI O H O O O
194 MIT-ML O H T O O
71 RAND-CSG D O O O O
8 SDC-ADEPT #D D #D #D #D
9 HARVARD-10 O O O D O
10 L.L.-360 H T H H R
74 L.L.-TX-2 O O O R O
11 STANFORD-AI H H H H T
13 CASE D D D D D
14 CMU-10 O O O D O
15 AMES-ILLIAC D T D D D
16 AMES-67 D H 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 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. 1/97 ]
AI ELI5
On this page
§1What the Report Covers
RFC 376 reports on the status of most network hosts from July 31 to August 4. It updates RFC 370. The author is Ellen Westheimer of BBN, and the closing note is signed by Alex McKenzie.
Some hosts were excluded from the daily testing because they were intended to be users only. These include the Terminal IMPs in the network (AMES, MITRE, RADC, NBS, ETAC, USC, GWC, NOAA, SAAC, ARPA and BBN) and the Network Control Center computer at network address 5, which only gathers statistics.
Some computers were only for visiting, not for sharing. They were left off the daily check.
§2The Host Table
The first table gives, for each host, its network address, site, computer, a status or prediction, and who supplied that information. Examples: address 1 at UCLA is a SIGMA-7 with a limited server, address 4 at UTAH is a PDP-10 server, and address 7 at RAND is an IBM-360/65 listed as user only.
A star marks a host not included in daily testing. The UCLA IBM-360/91 offered only a Network Job Service (NETRJS), which the BBN Terminal IMP could not test, so the report assumes that a connection to the NETRJS logger means NETRJS works.
The table is like a phone book with a note beside each name saying whether that computer was ready to help visitors.
§3How Each Test Is Graded
The second table gives one letter per host for each of five test dates. The letters are:
OOpen: the host opened a connection and was accessible to users.HHalf open: it opened a connection, then closed it or stopped responding.FFull: it said all network ports were in use and closed.RRefused: it returned a CLS to the initial RFC.TTimed out: no ICP completed within 60 seconds.DDead: the host was dead or inaccessible from the BBN Terminal IMP.
Some sites advertised that their systems might not be available at certain times, and those are marked with a hash.
Each computer got a letter: O for open and ready, D for dead, T for too slow to answer, and a few more for in-between cases.
- OOpen — Host opened a connection and was accessible to users.
- H1/2 Open — Host opened a connection but then closed it or did not respond.
- FFull — Host said all network ports were in use and closed.
- RRefused — Host returned a CLS to the initial RFC.
- TTimed out — No ICP and connection within 60 seconds.
- DDead — Host dead or inaccessible from the BBN Terminal IMP.
§4End of the Series
A note says Ellen Westheimer left BBN to return to school on August 4, so publication of these summaries would be discontinued. The author hoped that more detailed survey data from UCLA-NMC would take their place, and points to survey information already available online at MIT-DMCG, described in RFC 308.
The person who kept the attendance sheet went back to school, so the sheet stopped. Other people were expected to take over the job.