[ih] "The First Router" on Jeopardy
Jack Haverty
jack at 3kitty.org
Tue Nov 23 09:48:17 PST 2021
The distinction I see is more about what a device doesn't do, rather
than just what it does.
The IMP routed packets, but did a lot more. It detected errors and
retransmitted packets as needed to provide a "reliable byte stream"
service. It did flow control to the host computers. It did
congestion control. Essentially, it had a functional equivalent of TCP
embedded in the IMP code. There was even a notion of supporting
multiple networks (there's a field in the packet header) to provide a
functional equivalent to IP, although AFAIK that multiple-network
capability was never implemented. It had mechanisms to recover from
failures. It had mechanisms to facilitate software changes without
human intervention.
A router routed, and that's pretty much all it did. It didn't maintain
order of data, or guarantee delivery, or prevent duplicates from being
delivered. It didn't recover from errors or congestion, except for an
unreliable attempt to inform the sender that something was wrong. All
of that kind of functionality was relegated to the attached host computers.
A Router, especially the early versions, just routed. An IMP did a lot
more.
Jack Haverty
On 11/23/21 7:09 AM, Jorge Amodio wrote:
>
> I guess it could be interesting to find out when the word router was
> introduced as a "device"
>
> Can't find yet anything concrete in those old documents, besides the
> reference to the routing algorithm, there is also the concept of the
> IMP performing path selection.
>
> Several documents describe the IMP doing "routing" but none of them
> define the IMP as just a "router"
>
> -J
>
>
> On Tue, Nov 23, 2021 at 8:45 AM vinton cerf <vgcerf at gmail.com
> <mailto:vgcerf at gmail.com>> wrote:
>
> yes, there is no dispute that the IMP did routing of packets. But
> except for Jack's comments, I have never referred to the IMP as a
> "router," which term I associated with various Internet packet
> switches.
>
> v
>
>
> On Tue, Nov 23, 2021 at 9:42 AM Jorge Amodio via Internet-history
> <internet-history at elists.isoc.org
> <mailto:internet-history at elists.isoc.org>> wrote:
>
> There is another mention of the "Routing Algorithm" on the
> 1972 memo from
> Crowther, Walden and Mimno, to Frank Heart/IMP Guys,
> describing the new
> routing algorithm.
>
> -J
>
> On Tue, Nov 23, 2021 at 8:34 AM Jorge Amodio
> <jmamodio at gmail.com <mailto:jmamodio at gmail.com>> wrote:
>
> >
> > BBN Report #1783 (1969) includes the addition of the
> "Routing Algorithm"
> > but it does not define the word "router" but the description
> implies that
> > the IMP with this algorithm acts as a router.
> >
> > Trying to find a copy of Report #1822 ....
> >
> > Cheers
> > Jorge
> >
> >
> > On Mon, Nov 22, 2021 at 2:50 PM Jack Haverty via
> Internet-history <
> > internet-history at elists.isoc.org
> <mailto:internet-history at elists.isoc.org>> wrote:
> >
> >> Watching Jeopardy from November 17, 2021, I was surprised
> to see a
> >> "clue" which was a picture of Len Kleinrock standing in
> front of the
> >> ARPANET IMP which has been preserved at UCLA. It was a
> clue under the
> >> category "It's a New Machine".
> >>
> >> The host read the clue:
> >>
> >> "In 1969, Leonard Kleinrock and his team sent the first
> message over the
> >> Internet with the first THIS, which now connects devices
> like modems."
> >>
> >> None of the contestants knew the answer, although one guessed
> >> "backbone", which isn't a bad guess. So the guest revealed
> the answer:
> >>
> >> "You're looking at the first router."
> >>
> >> My immediate reaction was "No, you're not! That's an IMP."
> >>
> >> See https://www.youtube.com/watch?v=Lmv1WKMGcDw
> <https://www.youtube.com/watch?v=Lmv1WKMGcDw> starting at
> about 1:29
> >>
> >> That's not quite like I remember it. Ginny Strazisar built
> the first
> >> switching device for the Internet to connect the ARPANET to
> the Packet
> >> Radio net, circa 1977. To me that was the genesis of the
> "Internet" -
> >> INTERconnecting of NETworks of a variety of types, using
> TCP/IP to glue
> >> it all together. But millions of people just learned
> otherwise.
> >>
> >> A historical tidbit -- Back in 1977 Ginny's system was called a
> >> "gateway", but later was renamed a "router". It's possible
> that I did
> >> the renaming. At BBN we were selling lots of packet
> switches, and
> >> sometimes customers asked for ideas on how to use their
> LANs in the
> >> network. Our sales people would tell them about the research
> >> activities, and the role of gateways, TCP/IP , and the
> Internet. But in
> >> many customers' minds that term "gateway" immediately set
> off alarm
> >> bells, because they had prior bad experience with
> "gateways" in their
> >> IBM networks, and didn't want anything to do with more
> "gateways". So
> >> I suggested calling them "routers" instead of "gateways",
> and suddenly
> >> the marketplace became much more willing to listen.
> >>
> >> Enjoy,
> >> Jack Haverty
> >>
> >>
> >> --
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> >>
> >
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