Traffic statistics (July 1972)
Monthly statistics on ARPANET host data traffic for July 1972.
McKenzie, A.M., "Traffic statistics (July 1972)", RFC 378, DOI 10.17487/RFC0378, August 1972, <https://www.rfc-editor.org/info/rfc378>.
@misc{rfc378,
series = {Request for Comments},
number = 378,
howpublished = {RFC 378},
publisher = {RFC Editor},
doi = {10.17487/RFC0378},
url = {https://www.rfc-editor.org/info/rfc378},
author = {A.M. McKenzie},
title = {{Traffic statistics (July 1972)}},
pagetotal = 3,
year = 1972,
month = aug,
} RFC text
Network Working Group A. McKenzie
Request for Comments: 378 BBN
NIC #11120 10 August 1972
Traffic Statistics (July 1972)
For several months BBN has been supplying ARPA with a monthly summary
of "Host packets output." In response to questions from several
sites, ARPA has agreed to allow us to publish these statistics in RFC
form also. Attached are the traffic statistics for the month of July
1972.
Please note that the numbers given are either monthly totals or
overall averages (i.e., based on 24 hours per day, seven days a
week). Thus, these numbers are not useful in determining peak
traffic conditions.
HOST THROUGHPUT SUMMARY
(PACKETS OUTPUT)
JULY 1972
MISSING DATA FOR 17
INTER- INTRA- AVG. DAILY
NODE NODE TOTAL INTERNODE DAYS
UCLA HOST 1 100083 74730 174813
UCLA HOST 2 1168305 78751 1247056
UCLA HOST 3 33544 11950 45494
-------- ------- --------
1301932 165431 1467363 43398 30
SRI HOST 1 952543 343616 1296159
SRI HOST 2 140338 4798 145136
-------- ------- --------
1092881 348414 1441295 36429 30
UCSB HOST 1 340463 271366 611829 11349 30
UTAH HOST 1 597722 2019417 2617139 19924 30
BBN HOST 2 2190851 434235 2625086
BBN HOST 3 105 188 293
BBN HOST 4 78153 7697 85850
-------- ------- --------
2269109 442120 2711229 75637 30
MIT HOST 1 106692 36493 143185
MIT HOST 2 262648 642765 905413
MIT HOST 3 393534 3061353 3454887
MIT HOST 4 132621 800019 932640
-------- ------- --------
895495 4540630 5436125 29850 30
RAND HOST 1 145953 7753 153706
RAND HOST 2 1117688 2767974 3885662
-------- ------- --------
1263641 2775727 4039368 42121 30
SDC HOST 1 871 623 1494 29 30
HARV HOST 1 184616 63963 248579
HARV HOST 2 9771 17938 27709
-------- ------- --------
194387 81901 276288 6480 30
LINC HOST 1 5470 2897 8367
LINC HOST 2 20431 34736 55167
LINC HOST 3 0 136843 136843
-------- ------- --------
25901 174476 200377 863 30
STAN HOST 1 453402 43346 496748 15113 30
ILL HOST 1 199597 481 200078 6653 30
CASE HOST 1 49 13 62 2 30
CARN HOST 1 175067 58896 233963
CARN HOST 2 0 12 12
CARN HOST 4 1 0 1
-------- ------- --------
175068 58908 233976 5836 30
AMES2 HOST 1 876411 8700 885111 29214 30
AMES1 HOST 1 29969 37857 67826
AMES1 HOST 3 2081967 35898 2117865
-------- ------- --------
2111936 73755 2185691 70398 30
MITRE HOST 3 555380 34 555414 18513 30
ROME HOST 3 315960 32 315992 10532 30
NBS HOST 1 15965 287 16252
NBS HOST 3 531756 172 531928
-------- ------- --------
547721 459 548180 18257 30
ETAC HOST 3 150462 175 150637 5015 30
TINK HOST 1 0 159872 159872 0 30
MC CL HAD NO TRAFFIC
USC HOST 3 783376 5232 788608 26113 30
GWC HOST 3 70982 52 71034 2366 30
NOAA HOST 3 44504 24 44528 1483 30
SAAC HOST 3 5909 20 5929 197 30
BELV HAD NO TRAFFIC
ARPA HOST 1 0 335053 335053
ARPA HOST 3 68838 50071 118909
-------- ------- --------
68838 385124 453962 2295 30
BBN T HOST 3 714884 2268976 2983860 23829 30
--------------------------------------------
TOTAL 15056880 13825310
DAILY AVERAGE 501896 460844
AVERAGE PER 17307 15891
NODE-DAY
PACKETS/MESSAGE (INTERNODE) 1.09
[ 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
Alex McKenzie at BBN reports on ARPANET traffic statistics for July 1972. BBN had been providing ARPA with monthly summaries of host packet output for several months. After requests from various sites, ARPA approved publishing these statistics as RFCs to give the broader network community visibility into traffic patterns.
The statistics count packets output from each host during July, distinguishing between inter-node traffic (packets sent to other hosts across the network) and intra-node traffic (packets used within a single host's processing).
BBN counted how many packets each computer sent out in July, either to other computers or to itself. They published these numbers so everyone could see the network's busiest spots.
§2Traffic Data and Interpretation
The report provides monthly totals and daily averages for each host across the network. Notably, the figures represent either monthly totals or 24-hour averages, so they do not show peak traffic conditions. MIT Host 3 generated the highest inter-node traffic in July with 3.4 million packets, while UCLA Host 2 generated 1.2 million packets and Rand Host 2 generated 3.9 million packets.
Some sites like CASE had very light traffic (just 62 total packets), while others like McCleod had no traffic at all. The report also tracks the average number of packets per message sent between different hosts, showing it was 1.09 in July.
MIT and UCLA had the most traffic. Some computers barely used the network at all. The network moved about one extra packet per message on average.
§3Network Usage Insights
The statistics reveal the usage patterns of early ARPANET: MIT, UCLA, and Rand were the heavy users, while many other sites generated minimal traffic. The split between inter-node and intra-node traffic shows which sites were using the network for actual inter-host communication versus local processing.
Total monthly traffic across all hosts exceeded 28 million packets, representing an average of about 502,000 inter-node packets per day across the entire network. These figures help explain why the ARPANET community was concerned with network reliability and performance.
MIT, UCLA, and Rand were the network's busy places. All together, the network moved about 28 million packets in July. The measurements showed the network was growing and getting real use.