[ih] Packet Radio and Why TCP

Thu Sep 1 05:13:08 PDT 2016

a variety of radios were developed, some by DARPA. Adding Preston Marshall,
now at Google, who was DARPA program manager for developing new radios and
testing the use of the delay and disruption tolerant Bundle Protocol
against TCP/IP in tactical environments. He may have additional information
about the path of tactical radio development after the packet radio program
ended in the 1980s.

v

On Wed, Aug 31, 2016 at 11:23 PM, Jack Haverty <jack at 3kitty.org> wrote:

> I wasn't directly involved in Packet Radio itself, but heard about it,
> mostly from Jim Mathis and (IIRC) Holly Nelson who were at most of the
> meetings.  Helicopters were definitely in the thought experiments, and
> even faster low-altitude aircraft, as users of communications.  But I
> think you're right that probably only land-mobile and high-altitude
> aircraft was possible to actually demo, at least at first.
>
> There were many problems to be solved (we all had lots of lists of
> "things that need to be worked on"), and packet radio with higher speed
> mobile platforms was probably one of them.  It involved not only
> power/weight/size but also things like routing protocols, which would
> likely have to be much faster to respond to changes.
>
> I never have heard how (or if) that early Packet Radio work evolved into
> "real" use in modern military systems.   E.G., do drones still use TCP,
> do they communicate with Packet Radio protocols, etc.   There's probably
> a good history story there for some future historian to uncover.
>
> /Jack
>
> On 08/31/2016 07:29 PM, Barbara Denny wrote:
> > In case people are interested,  various packet radio efforts did
> > actually have demos for the military that utilized a hummer or an Air
> > Force airplane besides the SRI bread/mobile van which is now sitting
> > outside the Computer History Museum. I am not aware of any packet radio
> > demos with helicopters.  I think power, weight, size issues probably
> > prevented this but feel free to correct if anyone knows otherwise.
> > Helicopters have been used in more recent MANET program demos for DARPA.
> >
> > barbara
> >
> > p.s.
> > Packet radios may have ended up on a boat too before I started working
> > on the project.  I believe SRI had access to a research vessel.
> >
> >
> > ------------------------------------------------------------------------
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> > Today's Topics:
> >
> >   1. Why TCP? (Jack Haverty)
> >   2. Re: Why TCP? (Vint Cerf)
> >   3. Re: Why TCP? (Brian E Carpenter)
> >   4. Re: Why TCP? (Vint Cerf)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Wed, 31 Aug 2016 14:43:24 -0700
> > From: Jack Haverty <jack at 3kitty.org <mailto:jack at 3kitty.org>>
> > Subject: [ih] Why TCP?
> > To: internet-history at postel.org <mailto:internet-history at postel.org>
> > Message-ID: <87d2d00a-361a-8ec1-b1cd-2e047a40df93 at 3kitty.org
> > <mailto:87d2d00a-361a-8ec1-b1cd-2e047a40df93 at 3kitty.org>>
> > Content-Type: text/plain; charset=utf-8; format=flowed
> >
> > [I changed the subject because I hate unsearchable subjects like
> > "...internet history digest..."]
> >
> > I think Dave's observation is a really important fact for future
> > historians - the Internet did not evolve in a vacuum.
> >
> > ARPANET was one of the first packet networks (I'll let others argue
> > about which was First...), but it was preceded by networks based on
> > phone lines and modems interconnecting terminals and computers.
> >
> > The ARPA Packet Radio net enabled communications between mobile
> > computers, moving around in jeeps and helicopters, by radio links.  But
> > it was preceded by AlohaNet in Hawaii, which interconnected the various
> > islands by radio.  AlohaNet was also the inspiration for Ethernet.  In
> > the early 1970s, Bob Metcalfe's office at MIT was three doors down the
> > hallway from mine as he wrote his thesis that spawned Ethernet.  I
> > remember hearing about AlohaNet from him.
> >
> > Later, SATNET interconnected sites using satellite links, also obviously
> > using radio for communications.  Unlike the packet radio environment,
> > the path of the satellites was highly predictable, and the massive dish
> > antennas on the ground didn't move at all.
> >
> > SATNET was subsequently adapted to create MATNET, a Navy project, that
> > used satellite dishes on ships for communication.  Ships moved of
> > course, but not as rapidly or spasmodically as jeeps and aircraft.
> >
> > Ethernet was evolved by Xerox PARC into its own "internet", with
> > multiple LANs interconnecting by radio links or telephone lines.
> > During the early 80s, The Internet which we still use today was running
> > in parallel with the PARC internet (I can't recall what they called it),
> > using PUP where we used TCP.
> >
> > As Dave noted, we got used to hearing that the mission of the Internet
> > Project (as driven by the IAB/ICCB under Vint's direction) was to
> > develop the infrastructure technology, i.e., protocols and algorithms
> > and standards, to interconnect these networks, both the existing types
> > and anything else that someone might dream up in the future.
> >
> > If some new type of network could carry packets from point A to point B,
> > it should be possible to incorporate it into the Internet --- without
> > requiring the host computers to change any software (which would be
> > hard), or change all of the routers in the Internet (only the ones that
> > directly interface to the new network need to change to be able to use
> it)
> >
> > We even mused about extreme networking.  For example, TCP/IP should be
> > able to utilize a "network" implemented using carrier pigeons for
> > transport, with each pigeon carrying a small tube with a strip of paper
> > containing one packet of data.
> >
> > As far as I know, no one ever did that....  But it was one of the
> > scenarios that came up in the brainstorming discussions to prevent us
> > from changing the technical mechanisms in a way that precluded
> > PigeonNet's use.
> >
> > On another extreme, we mused about incorporating another Internet into
> > The Internet, i.e., using some existing set of routers and lines
> > (Internet 1), as a means to interconnect routers in an overlaid internet
> > (Internet 2).  After all, a fragment of an internet meets the
> > definition of a network - a communications mechanism that can carry
> packets.
> >
> > As far as I know, such multi-layer Internet-of-Internets *did* happen.
> > It was used in some secure environments and I think also used as a
> > technique to implement the IP4 to IP6 transition (are we there
> > yet...it's been more than 30 years!???)
> >
> > So, as Dave noted, TCP/IP was developed as an overlay that would run
> > over all existing, or future, networks.  That goal often came up during
> > the meetings and discussions as something akin to a Prime Directive.
> >
> > ==============
> >
> > IMHO, future historians might also like to know *why* that was the Prime
> > Directive.  In other words, Why TCP?  The intransigence of people to
> > settle on a single technology and protocol was important as a motivator,
> > but IMHO only part of it.
> >
> > My introduction to TCP was in 1977.  I had been working in the ARPANET
> > environment, doing things like email et al at MIT.  I moved to BBN in
> > 1977 and my first task was to write the first TCP for Unix, which was
> > needed as part of an ARPA project.  At that time, TCP was at the version
> > 2.5 stage.
> >
> > Over the next year or so, we made a lot of changes to create TCP 3 and
> > then TCP 4.
> >
> > Creating a technology that could incorporate any kind of network was a
> > big part of the mission.  But there were others.  For example, it was
> > desirable that the infrastructure support different types of user
> > traffic.  Ideally, the TCP infrastructure would support all types of
> > user traffic in a way similar to its ability to utilize any type of
> > network that might appear.
> >
> > Specifically, voice traffic - realtime human-human speech - was found to
> > not work very well over a TCP connection.  With our traditional uses,
> > e.g., FTP/Telnet/Email, getting all of the data there intact was the
> > overriding goal.  In speech, getting the data there in a timely fashion
> > was most important, and some loss of snippets of speech was acceptable.
> >
> > That, among other things, motivated the split of TCP into TCP/IP,
> > allowing the creation of UDP and "higher" protocols to carry things like
> > speech and video.
> >
> > =======================
> >
> > All of these internet-history discussions tend to revolve around
> > technology - protocols, algorithms, etc., which isn't surprising since a
> > lot of the people on this list were deeply involved in creating that
> > technology.
> >
> > But for the benefit of historians, there's another "layer" of discussion
> > that seems important - Why TCP?  In other words, why was it so important
> > to create a whole new infrastructure with such capabilities.
> >
> > The Departments of Defense (note plural) put quite a lot of money into
> > the efforts to develop the Internet technology.  ARPA, part of the US
> > military, was a large player, acting as a conduit for funds from the
> > various parts of the military - Army, Navy, Air Force, etc.  But other
> > players from other countries were there too - RSRE (UK), NDRE (Norway),
> > DFVLR (Germany), and CNUCE (Italy) are ones I remember.
> >
> > So, .... the interesting question is "Why did they send money, and keep
> > sending it, to create the TCP/IP technology"?  Why did they care about
> > being able to interconnect all sorts of networks?
> >
> > The answer of course is because they needed it to solve their own
> > communications problems.
> >
> > During that TCP2-->4 evolution period, I remember that we were
> > continuously aware of stereotypical military scenarios in which TCP was
> > supposed to operate.  The military folks didn't really care about bits,
> > bytes, packets, etc.  They just knew what they wanted to be able to do
> > with it all.
> >
> > The scenario I remember most was what I heard on joining the fray in
> > 1977 and learning what exactly this "TCP" thing and associated projects
> > were all about.
> >
> > It was a "Command and Control" scenario, which is the bread-and-butter
> > of the military world.  The notion was that someone "out in the field",
> > perhaps a scout in a jeep, would see something interesting, and need to
> > report it up the command chain.  "I see a column of tanks coming along
> > the river valley".
> >
> > The jeep of course couldn't be wired into an IMP port on the ARPANET.
> > But it could have a radio, and that radio should be able to communicate
> > with another jeep, or tank, or whatever else might be around.  And they
> > might be able to communicate with the field headquarters, possibly
> > several miles away.  But everyone had to be able to move, often rapidly
> > and unpredictably.
> >
> > So, .... here's some money....make it work... and Packet Radio networks
> > were born.
> >
> > With lots of jeeps, or helicopters, or whatever, and their eyes and
> > ears, the field headquarters could be connected back to the Pentagon
> > over the ARPANET and all of that information could be used to figure out
> > what to do about it.  But somehow we need to have messages flow from the
> > Packet Radio to the ARPANET...
> >
> > So, .... here's some money....make it work.... and gateways (aka
> > routers) were born.
> >
> > Back at the Pentagon, looking at all the reports, it might become clear
> > that the Army guys in the jeeps needed a little help as waves of tanks
> > approached them.
> >
> > Perhaps there's a ship offshore, with some big guns, and a carrier full
> > of nasty airplanes.  But they're over the horizon, too far away for the
> > Packet Radio to reach, or for wires to an IMP port.  But they do have
> > satellite dishes, and can talk to other dishes halfway around the planet
> > if necessary.  If only their computers could talk with everybody else...
> >
> > So, here's some money....make it work.... and SATNET and MATNET were
> > born.  The USS Carl Vinson was on The Internet.
> >
> > When things get frenetic, messages and email just aren't fast enough.
> > Real time voice communication is critical (remember, no cell phones in
> > those days).  But voice over TCP isn't working well.
> >
> > So, here's some money....make it work.... and TCP is split into TCP and
> > IP, UDP is defined, and the obstacle to realtime voice is removed.  Hey,
> > it should even work for video someday.
> >
> > We can't do video, but graphics are a big help.  A general might be able
> > to view a map while talking with commanders in the field who see the
> > same map.  Even use a pointer to highlight specific areas of the map as
> > he gives instructions.  "Unit A, you move here (pointing somewhere),
> > and Ship B, you fire at this location (pointing somewhere else)".
> >
> > It's really important that the "pointing" actions in the graphics are
> > well-synchronized with the speech giving the commands......
> >
> > So, the real-time UDP speech needs to be time-synched with the graphics
> > images over TCP.
> >
> > So, here's some money....make it work....and .... mechanisms such as NTP
> > (thank you Dave Mills!) are created to provide high-accuracy global
> > time.  But I have no idea if the voice/graphics synching is guaranteed
> > even today.  Sure hope so...
> >
> > There were a number of these scenarios that drove our thinking about the
> > problems.  I was an initial member of Vint's IAB (then called ICCB), and
> > these kinds of scenarios played a significant role in those discussions,
> > which complemented the technical discussions in the larger Internet
> > group meetings.  The IAB in part acted as a conduit to translate the
> > desires of the guys with the money into the technical goals that drove
> > the creation of the TCP/IP protocols and machinery.
> >
> > Someone (I wish I knew who) made the decision to do all of this work,
> > and spend all of that money, in an open environment, and make the
> > technology freely available and standardized for anyone to use.  None of
> > the competing Internet architectures (Xerox, Novell, DEC, IBM, ISO,
> > etc.) did that.  So when the rest of the world discovered that the
> > military TCP/IP technology not only worked but also could solve their
> > problems, the ascension of the Internet was natural.
> >
> > So, that's why we have TCP!
> >
> > As usual, I've written a lot, sorry about that.  It just seems important
> > to get this written down somewhere to capture some of the "why" part of
> > the Internet history.  The existence of concrete scenarios was key in
> > focusing the technical work on actual real-world problems to be solved.
> > That permeated the culture of the Internet developers.  Instead of
> > writing documents, we wrote code...
> >
> > /Jack Haverty
> > August 31, 2016
> >
> >
> >
> >
> > On 08/31/2016 07:17 AM, Dave Crocker wrote:
> >> On 8/31/2016 6:50 AM, Craig Partridge wrote:
> >>> As I recall the story (I arrived on the scene later), Bob Kahn was in
> >>> the process of funding Packet Radio Networks and he and Vint needed to
> >>> solve the
> >>> interconnection problem and that motivated the TCP paper.
> >>
> >>
> >> This is a variant of the broader problem statement I was used to
> hearing:
> >>
> >>      Even by 1972 there already were a variety of independent networks
> >> around the world.  How to interconnect them, since it was unlikely that
> >> they would all agree to switch over to someone else's network protocols.
> >>
> >>      TCP was developed as an overlay that would run on all of them,
> >> connecting them.
> >>
> >> d/
> >>
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Wed, 31 Aug 2016 18:29:05 -0400
> > From: Vint Cerf <vint at google.com <mailto:vint at google.com>>
> > Subject: Re: [ih] Why TCP?
> > To: Jack Haverty <jack at 3kitty.org <mailto:jack at 3kitty.org>>
> > Cc: internet history <internet-history at postel.org
> > <mailto:internet-history at postel.org>>
> > Message-ID:
> >     <CAHxHggd8=NHr6T-j89ANp+sDOYak8sVtV1YyQs3EDfZYc9rAxA at mail.gmail.com
> > <mailto:sDOYak8sVtV1YyQs3EDfZYc9rAxA at mail.gmail.com>>
> > Content-Type: text/plain; charset="utf-8"
> >
> > On Wed, Aug 31, 2016 at 5:43 PM, Jack Haverty <jack at 3kitty.org
> > <mailto:jack at 3kitty.org>> wrote:
> >
> >>
> >> We even mused about extreme networking.  For example, TCP/IP should be
> >> able to utilize a "network" implemented using carrier pigeons for
> >> transport, with each pigeon carrying a small tube with a strip of paper
> >> containing one packet of data.
> >>
> >> As far as I know, no one ever did that...
> >
> >
> > yeah, they did - there's even an RFC about it, I think, from UK.
> >
> >
> > see also YouTube: https://www.youtube.com/watch?v=XQCZH9Lp8uo
> >
> > The audio and auto-caption is hilariously disconnected.
> >
> > https://entertainment.slashdot.org/story/09/08/29/
> 1934251/pigeon-protocol-finds-a-practical-purpose
> >
> > http://www.cnet.com/news/pigeon-powered-internet-takes-flight/
> >
> > v
> > <http://www.cnet.com/news/pigeon-powered-internet-takes-flight/>
> >
> > --
> > New postal address:
> > Google
> > 1875 Explorer Street, 10th Floor
> > Reston, VA 20190
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> >
> > ------------------------------
> >
> > Message: 3
> > Date: Thu, 1 Sep 2016 10:31:16 +1200
> > From: Brian E Carpenter <brian.e.carpenter at gmail.com
> > <mailto:brian.e.carpenter at gmail.com>>
> > Subject: Re: [ih] Why TCP?
> > To: Jack Haverty <jack at 3kitty.org <mailto:jack at 3kitty.org>>
> > Cc: internet-history at postel.org <mailto:internet-history at postel.org>
> > Message-ID: <50804405-fff3-c6cb-421a-44d1bf08ab2c at gmail.com
> > <mailto:50804405-fff3-c6cb-421a-44d1bf08ab2c at gmail.com>>
> > Content-Type: text/plain; charset=utf-8
> >
> > On 01/09/2016 09:43, Jack Haverty wrote:
> > ...
> >> For example, TCP/IP should be
> >> able to utilize a "network" implemented using carrier pigeons for
> >> transport, with each pigeon carrying a small tube with a strip of paper
> >> containing one packet of data.
> >>
> >> As far as I know, no one ever did that....
> >
> > Of coure they did:
> > http://www.blug.linux.no/rfc1149/writeup/
> >
> >   Brian
> >
> >
> >
> > ------------------------------
> >
> > Message: 4
> > Date: Wed, 31 Aug 2016 18:35:06 -0400
> > From: Vint Cerf <vint at google.com <mailto:vint at google.com>>
> > Subject: Re: [ih] Why TCP?
> > To: Jack Haverty <jack at 3kitty.org <mailto:jack at 3kitty.org>>
> > Cc: internet history <internet-history at postel.org
> > <mailto:internet-history at postel.org>>
> > Message-ID:
> >     <CAHxHggfi9-LNbV71bUSX6ozkX=GTtioTLdVTMk2EhBi_Y-Z3wg at mail.gmail.com
> > <mailto:GTtioTLdVTMk2EhBi_Y-Z3wg at mail.gmail.com>>
> > Content-Type: text/plain; charset="utf-8"
> >
> > On Wed, Aug 31, 2016 at 5:43 PM, Jack Haverty <jack at 3kitty.org
> > <mailto:jack at 3kitty.org>> wrote:
> >
> >>
> >> Someone (I wish I knew who) made the decision to do all of this work,
> >> and spend all of that money, in an open environment, and make the
> >> technology freely available and standardized for anyone to use.  None of
> >> the competing Internet architectures (Xerox, Novell, DEC, IBM, ISO,
> >> etc.) did that.  So when the rest of the world discovered that the
> >> military TCP/IP technology not only worked but also could solve their
> >> problems, the ascension of the Internet was natural.
> >
> >
> > Bob Kahn, Larry Roberts and Dave Russell are probably the closest to the
> > deciding parties
> > at the IPTO level but one has to credit George Heilmeier and Steve
> Lukasic
> > as DARPA
> > Directors for their strong support for ARPANET and then Internet.
> >
> > v
> >
> >
> >
> > --
> > New postal address:
> > Google
> > 1875 Explorer Street, 10th Floor
> > Reston, VA 20190
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-- 
New postal address:
Google
1875 Explorer Street, 10th Floor
Reston, VA 20190
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