[ih] when did APRANET -TIPs become known as -TACs

Sun Sep 28 22:30:32 PDT 2025

another aspect of "The PTT vision" was that of different type/kind of
"split with respect to "settlements" for "the connection time, distance and
characters transmitted" where indeed "the TCP/IP suite was that it did not
include such a split" the X.25/X.75 networks divvied up/"shared" the "loot"
between them -- just like was done for long distance toll calls between
intra country carriers/regions as well as inter country/internationally...

it's worth additionally noting that there was an "attempt" to "import" (a
polite way of putting it :) and implement the PPT intercarrier revenue
"settlements" splitting into/into the Internet with/by ANS CO+RE..., viz.:

*Data Network Raises Monopoly Fear*
By JOHN MARKOFF
The New York Times
December 19, 1991
http://www.nytimes.com/1991/12/19/business/data-network-raises-monopoly-fear.html

g

On Sun, Sep 28, 2025 at 6:00 PM Brian E Carpenter via Internet-history <
internet-history at elists.isoc.org> wrote:

> The PTT vision was based on a monopoly charging for connection time,
> distance and characters transmitted. X.25 plus X.75 fitted that vision
> well. Remember that there was a long period during which Judge Greene's
> ruling applied in the US, but the traditional monopolies were still in
> place in Europe (and Asia). That's why US GOSIP was so different from
> European GOSIP, so OSI was split into two visions. The main attraction of
> the TCP/IP suite was that it did not include such a split.
>
> Regards/Ngā mihi
>     Brian Carpenter
>
> On 29-Sep-25 12:13, John Day via Internet-history wrote:
> > I am sorry Jack, but X.25 was the bane of OSI forced on it by the PTTs.
> It was part of PTT vision, but everyone knew it was a dead-end and had been
> since 1976, when it first appeared. It epitomized what was wrong with
> PTT-think. They had no clue about networking and still don’t.
> >
> > The OSI vision was, if anything, Ethernet (an ISO standard), CLNP, TP4,
> and ACSE.
> >
> > Take care,
> > John
> >
> >> On Sep 28, 2025, at 18:14, Jack Haverty via Internet-history <
> internet-history at elists.isoc.org> wrote:
> >>
> >> Hi Barbara,
> >>
> >> X.25 made it easier to connect hosts to IMPs.   ARPA had funded lots of
> computers used in the research community to have someone build 1822
> interfaces.   But there were lots of other computers used outside the
> research environment.  X.25 was a key part of the OSI vision, and computer
> manufacturers were much more likely to create an X.25 interface for their
> products than an 1822 interface.
> >>
> >> I don't think this really affected the choice of IMPs versus directly
> connecting routers with wires.  Part of an X.25 interface was the basic
> physical connection for a wire, and it was straightforward to just
> interconnect routers with a wire by using that same physical interface with
> no X.25 connection management sofware needed.
> >>
> >> At one point at BBN we noticed that a wire was really just a very basic
> "network" that could be used to interconnect gateways.  A wire was
> effectively a "class F" network with just 2 possible attached computers -
> "this end" and "the other end".  We actually tried connecting two gateways
> together with a wire instead of using the ARPANET and it worked fine.
> >>
> >> At one point (can't remember exactly when) I was responsible for "DDN
> System Engineering", and frequently got called to Washington for various
> meetings.   One of them was to hear some startup's pitch for how DDN could
> use their products.  After the pitch, everyone turned to me and the guy in
> charge asked "Will this work?".   I think they expected me to say it was a
> silly idea and they really needed to use BBN's solutions.  But, as a DDN
> consultant, I said "Yes, it should."   They got a testbed running, and the
> startup no doubt realized the same thing that we (and SRI later) did - you
> didn't really need the IMP in the picture.  BTW, that startup was Cisco
> Systems.
> >>
> >> I'm not sure when I first heard PSN as the acronym for Packet Switched
> Node.  My recollection is that the terminology came out of the OSI vision
> which had become very popular.  IMP stood for Interface Message Processor
> but that name was always confusing.  I remember there was an IMP somewhere
> with a clipping pasted on its front panel -- a message had come in from a
> US government Senator, congratulating someone (ARPA?  BBN?) on their
> successful creation of the "Interfaith Message Processor"  (read the last
> three words carefully).   There's a writeup at
> https://foxmancommunications.com/the-interfaith-message-processor-and-the-tower-of-babel/
> >>
> >> It was an interesting time.
> >>
> >> Jack
> >>
> >> On 9/28/25 12:19, Barbara Denny via Internet-history wrote:
> >>>   Do you think the obsolescence of 1822 in favor of X.25 just made it
> easier to get rid of IMPs in the networks?
> >>> I am thinking about the military testbed for USAREUR where I think the
> original deployment had CXXs (don't remember if it had C30s or C70s but
> leaning towards C30s).  It was deployed in that timeframe. It originally
> had IMPs and Cisco AGS routers  but I think SRI pulled the IMPs and just
> used the routers very soon after it was originally installed.
> >>> BTW, what is the story for replacing the IMP term for PSN (Packet
> Switching Node) and when was this done?
> >>> barbara
> >>>      On Sunday, September 28, 2025 at 10:08:29 AM PDT, Jack Haverty
> via Internet-history<internet-history at elists.isoc.org> wrote:
> >>>     On 9/28/25 06:31, Noel Chiappa via Internet-history wrote:
> >>>>        > From: Jack Haverty
> >>>>
> >>>>        > Much of this history was probably well-documented in the
> reports
> >>>>        > submitted by BBN ... It may be available on
> discover.dtic.mil
> >>>>
> >>>> I took your suggeation, and turned up an answer to one question: there
> >>>> were C/30-based TACs, as well as one-time-TIP-based TACs.
> >>>>
> >>>>      Combined Quarterly Technical Report No. 22
> >>>>      https://apps.dtic.mil/sti/pdfs/ADA104931.pdf
> >>>>      Combined Quarterly Technical Report No. 23
> >>>>      https://apps.dtic.mil/sti/pdfs/ADA108783.pdf
> >>>>      The DDN (Defense Data Network) Course
> >>>>      https://apps.dtic.mil/sti/tr/pdf/ADA173472.pdf
> >>>>
> >>>> I found nothing about what physical interface any of them used,
> though,
> >>>> but I'll bet it was an 1822.
> >>>>
> >>>>      Noel
> >>> Hi Noel,
> >>>
> >>> Yes, good detective work.  There's lots of information in contractor
> >>> reports.  At every Internet Meeting there were a lot of contractors, so
> >>> the reports from each were limited to 15 minutes or so.   Much of the
> >>> detail wasn't even presented in the meetings, and of course not
> captured
> >>> in Jon's minutes.
> >>>
> >>> There's lots of technical detail in those old reports that probably
> >>> should have been issued also as RFCs or IENs.  The reports went to
> >>> various parts of the government, and to the people inside BBN who had
> >>> worked on the projects, but probably not much beyond those groups.  For
> >>> example, I assume all the other ARPA contractors had to submit similar
> >>> reports.   But I don't recall ever seeing a report from SRI, MIT, UCLA,
> >>> Linkabit, Collins, or any of the other contractors who attended the
> >>> various Internet meetings.   I still haven't seen more than a handful
> of
> >>> non-BBN reports, but I suspect some might be in DTIC.
> >>>
> >>> At some point I was given responsibility for all of the ARPA and
> related
> >>> contracts in our part of BBN.   That meant I became the "author" of the
> >>> BBN reports.  Pragmatically what it meant was that I had to badger all
> >>> of the project leaders to write down what their teams did during the
> >>> quarter.   Getting blood out of a stone would have been easier than
> >>> getting documentation out of an engineer.  For many of our contracts,
> >>> the only required deliverables were the Quarterly Reports.   Until the
> >>> Report was submitted, the government wouldn't pay the bill.
> >>>
> >>> BTW, re C/30 et al.  Internet History has probably never been told
> about
> >>> that part of the history:
> >>>
> >>> The C/30 hardware was based on a BBN project called the MBB -
> >>> Microprogrammable Building Block.  As the name implies, the hardware
> was
> >>> microprogrammable.  The C/30 microcode was designed to make an MBB look
> >>> exactly like a Honeywell 316.  So the same code that had been developed
> >>> for the 316-based IMPs (or TIPs) would also run on a C/30.
> >>> Effectively, a C/30 looked exactly like a Honeywell 316 to the software
> >>> that ran on it.
> >>>
> >>> Similarly, a C/70 was a Unix minicomputer also built on an MBB, but
> with
> >>> an interface to disk storage and probably more RAM.  The MBB microcode
> >>> used for a C/70 was optimized for code written in the C language, which
> >>> was the language used by the Unix OS.
> >>>
> >>> BBNCC started life as BBN Computer Corporation, with a plan to sell
> Unix
> >>> boxes to the world.   Competing with DEC was probably always a bad
> idea,
> >>> so later BBNCC became BBN Communications Corporation, selling IMPs to
> >>> the marketplace as ARPANET clones, and a few C/70s operating as NOCs.
> >>> Didn't even have to change the logo.
> >>>
> >>> There was also a C/60, but I can't remember what it did.....
> >>>
> >>> There's probably lots of detail in other old BBN reports, as well as
> >>> reports from others.  For example, I just searched in DTIC for "BBN
> MBB"
> >>> and found this discussion about formal verification of the C/30
> >>> microcode:https://apps.dtic.mil/sti/tr/pdf/ADA510573.pdf   -- which
> >>> even found bugs in the microcode.  Another timeline bit in that report
> -
> >>> the 1822 interface was obsolete on DDN by 1986, in favor of X.25 for
> the
> >>> Host/IMP interface.
> >>>
> >>
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