[ih] AOL in perspective

[Jack Haverty]

This "network status" usage was, IMHO, the beginning of a fundamental 
shift in how networks were used, and influenced how they were 
subsequently designed.

In the early ARPANET era (1970s), network traffic was dominated by 
Telnet, FTP, and a bit later email.  Human users connected to their 
computers using Telnet and worked for the duration of a "session", which 
lasted for minutes or perhaps hours.  During that session, they might 
also do file transfers between two computers.  The ARPANET was pretty 
slow, so file transfers could easily take minutes or more.  Sessions 
between two ARPANET hosts were relatively long and infrequently opened 
or closed.

So network traffic was largely short packets containing typing and 
responses, as well as larger packets associated with file transfers, 
mostly part of sessions lasting minutes or more.

Email added to this traffic with the addition of non-human users, i.e., 
mail servers, who transported mail around the net, including short 
messages as well as long documents.  But email servers were pretty 
patient compared to humans, and certainly didn't expect to see the 
characters they sent echoed immediately.

The internal mechanisms of the ARPANET (i.e., the mechanisms inside the 
IMP code) were designed to carry that mix of traffic - interactive and 
bulk transfers, carried out over "sessions".   In particular, there were 
IMP mechanisms to set up end-to-end connections between the source and 
destination IMPs (not the attached hosts).  Those mechanisms created the 
reliable "virtual circuit" behavior, on top of the underlying unreliable 
packet switching machinery.  The IMPs delivered a "virtual circuit" 
reliable byte-stream service to their hosts - much like TCP does now 
between two devices on the Internet.   For anyone curious, the 1970s 
ARPANET IMP code has been resurrected and is available online.

Marc Seriff's SURVEY program broke the ARPANET traffic pattern. Sessions 
in SURVEY were extremely short, unlike sessions in human-based traffic.  
I wasn't at BBN at the time (actually I was in Lick's group at MIT, same 
as Marc), but I suspect part of the backlash Marc received about SURVEY 
was because it was seriously "thrashing" the ARPANET with so many short 
connections continuously happening.  The ARPANET wasn't designed for 
that kind of continuous very short session traffic load.

Several years later, circa 1980, we had a similar experience with the 
ARPANET and the emerging Internet which was being built around it.  Lots 
of now inexpensive minicomputer gear had appeared on the Internet, 
connected by LANs to the ARPANET.  I was the "Internet guy" at BBN, and 
one day a NOC operator stuck his head in my office and said something 
like "What's your Internet doing!!?"  It was probably a bit more 
colorful than that.  The ARPANET was thrashing again, and the NOC had 
traced the problem to traffic to/from gateways.   That made it my problem.

Debug, XNET, SNMP, ... IIRC, it turned out that Berkeley had just 
released a new version of BSD, and announced it to the user community.  
There were a lot of BSD systems out there.   The new BSD included a new 
feature, that probed all the gateways out on the ARPANET and generated a 
status report of "State of the Internet". Updated automatically of course.

The server that performed all that probing was part of the new OS 
release.  And... it was "enabled" by default.   So as the new release 
propagated out into all those systems, they all started probing every 
gateway continuously.   Like Marc's SURVEY program, this caused the 
ARPANET to internally hemorrhage.   A quick call to ARPA, and a quick 
order to Berkeley, and the cyberattack stopped. Took a while IIRC.

Looking back over the history, I see this as the progression of 
networking from the "human user" model of Telnet and FTP towards the 
model Licklider had envisioned in his "intergalactic network". Instead 
of humans interacting with remote computers, we were beginning the 
transition to computers interacting with each other over the Internet, 
in support of whatever humans wanted done.   That was Lick's vision - 
everyone would have their own computer, all able to communicate with 
each other, and active all the time.  Pretty much seems like what we 
have today.

I don't have the data, but I suspect the mix today of interactive/bulk 
traffic is quite different from what it was 50 years ago.  There's 
probably not a lot of Telnet-style activity any more.  But perhaps the 
growing population of "IOT" microcomputers will replace it.

Jack Haverty

On 9/4/25 17:27, John Day via Internet-history wrote:
> There were complaints when it disappeared, but it also gotten too popular.
>
>> On Sep 4, 2025, at 20:25, Vint Cerf<vint at google.com> wrote:
>>
>> I had forgotten about that!
>>
>> Please send any postal/overnight deliveries to:
>> Vint Cerf
>> Google, LLC
>> 1900 Reston Metro Plaza, 16th Floor
>> Reston, VA 20190
>> +1 (571) 213 1346
>>
>>
>> until further notice
>>
>>
>>
>>
>> On Thu, Sep 4, 2025, 19:57 John Day via Internet-history <internet-history at elists.isoc.org <mailto:internet-history at elists.isoc.org>> wrote:
>>> In the very early days, the NMC at UCLA did something similar. If you connected to a particular well-known socket, it would print a ASCII map of the current ARPANET and which hosts were up or down. It was discontinued when it would no longer fit on one page.
>>>
>>> Take care,
>>> John
>>>
>>>> On Sep 4, 2025, at 10:42, Lars Brinkhoff via Internet-history <internet-history at elists.isoc.org <mailto:internet-history at elists.isoc.org>> wrote:
>>>>
>>>> Speaking of.  Marc Seriff was one of the co-founders of AOL.  He had
>>>> previously been part of the MIT Dynamic Modeling group.  He (along with
>>>> Bob Metcalfe and others) had a hand in making the ARPANET "SURVEY"
>>>> program, which would probe network hosts to see if they were up.  Marc
>>>> told me this:
>>>>
>>>>   "I tell the story of SURVEY all the time.  For a few days, the whole
>>>>   ARPANET was pissed at me since, in those days, all the systems logged
>>>>   every connection attempt - typically to a model 33 teletype machine
>>>>   sitting in front of the PDP/10 or whatever.  A decent system since the
>>>>   few computers on the network at the time weren't likely to get more
>>>>   than a few connections a day.  All of sudden, I'm poking them once a
>>>>   minute or so.  System managers would come in in the morning to find
>>>>   paper piled behind the teletype and, frequently, ink ribbons that had
>>>>   been torn to shreds!"
>>>>
>>>> They program has been recovered and seems to be working, lacking only an
>>>> ARPANET to survey.  Watch your teletypes!
>>>>
>>>> Survey results were stored on the Datacomputer (also located in MIT's
>>>> Tech Sq building.)
>>>> -- 
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