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Leonard Klienrock - The First Two Packets on the Internet

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互联网的历史、技术和安全

密歇根大学

4.8（1,715 個評分） | 100K 名學生已註冊

The impact of technology and networks on our lives, culture, and society continues to increase. The very fact that you can take this course from anywhere in the world requires a technological infrastructure that was designed, engineered, and built over the past sixty years. To function in an information-centric world, we need to understand the workings of network technology. This course will open up the Internet and show you how it was created, who created it and how it works. Along the way we will meet many of the innovators who developed the Internet and Web technologies that we use today. What You Will Learn: After this course you will not take the Internet and Web for granted. You will be better informed about important technological issues currently facing society. You will realize that the Internet and Web are spaces for innovation and you will get a better understanding of how you might fit into that innovation. If you get excited about the material in this course, it is a great lead-in to taking a course in Web design, Web development, programming, or even network administration. At a minimum, you will be a much wiser network citizen.

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Internet Architecture, Internet, Internet Security, Internet Protocol (IP) Suite

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4.8（1,715 個評分）

5 stars
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SI

Apr 26, 2019

Great Instructor! I have learnt alot from this course as well as the instructor. I am thankful to coursera for providing me this opportunity to learn from an instructor like Dr. Charles Severance.

JM

Jun 15, 2016

Dr. Chuck is the best!! The interviews with the Grandfathers and Innovators of the Internet are AWESOME! I highly recommend this class to everyone, you will definitely enjoy it tremendously.

從本節課中

History: The First Internet - NSFNet

In the 1960s and 1970s, there was a great deal of research done to build the first wide-area packet switched networks for the US Department of Defense. In the 1980s, the first “Internet” was formed to allow academic researchers to access supercomputer resources.

History Through NSFNet3:13

Doug Van Houweling - NSFNet13:14

Leonard Klienrock - The First Two Packets on the Internet13:11

Katie Hafner - Where Wizards Stay Up Late12:05

教學方

Charles Russell Severance
Professor

腳本

[MUSIC]

When you walk into the back entrance of Boelter Hall on the UCLA campus,

you may notice a seemingly random pattern of floor tiles on the entrance.

If you spend a little time looking at the pattern,

it might dawn on you that the tiles represent zeros and ones and

then you might even figure out that the tiles represent as ASCII characters.

The characters in the floor tiles spell out low and behold.

To commemorate the building where L and O, where the first two packets ever sent on

the ARPANET from UCLA to Stanford Research Institute, on October 29th, 1969.

[MUSIC]

>> ARPA wanted a network so that they could share the large computing resources

they had given to their researchers across the country.

University of Utah had a terrific graphics operating system, SOI database,

we had simulations.

University of Illinois had high-performance computing.

And every time ARPA brought on a new researcher,

they'd offer to buy him a computer, fine, but the researcher would say,

I want the same capability all those other guys have.

I want the graphics, the database, and all of that.

And ARPA said, we can't afford that.

If you want to do graphics,

you log onto the machine at Utah, to a network that we think we're going to make.

So, the need for the network was to do resource sharing, and

not to protect the United States against a nuclear holocaust.

When Bob Taylor came in as net director, and he recognized this need for

sharing resources, by the way, notice the phrase I'm using,

sharing resources is exactly what I built into the network design.

Now they want it to share the external resources.

Same idea, you have it, you're not using it, somebody else should be able to.

So they brought in Larry Roberts, another classmate of mine, in fact,

an officer of mine at MIT to manage this project.

He came to me, because he knew my work.

He watched me do the simulation.

In fact, I used his compiler on the TX2 computer and said,

Len we need to know if this thing's going to work.

He knew that I had a theory, so I could show it to him it's going to work.

In fact, he even says he would never have decided to spend millions of dollars of

the US Government's money.

It wasn't sure this thing would work.

So the design began to be laid out by a few of us in 1967,

in 68 they sent out a request for proposal.

The end of 68, Bolt, Beranek and Newman, a Cambridge,

Massachusetts firm won the contract to produce the first switch of the opener.

And we became the network measurement center early on so we could test it out.

During the design phase, some great people were there throwing their ideas out.

Herb Baskin was there, a timesharing expert.

And he said, if this network can't deliver short messages within a half a second,

I can't use it for timesharing.

[NOISE] Specification.

Half a second.

By the way we got 200 milliseconds.

[LAUGH] And Westclock said,

separate computer from communications.

I said, look if this is going to be an experiment.

And I also was interested in the research and the experimentation.

We have to build to build software in so we can run experiments.

Artificial traffic generators, measurement hooks,

a place where the measurements can be evaluated, put that software in.

So how we find, begin to talk about network reliability.

If anything fails, the network shouldn't collapse.

So, we didn't say these should be five nines of uptime.

We want much more pragmatic,

we said if any single thing fails, everybody else can still talk.

So to do that you need something called a two connector topology,

two independent pairs between every pair of nodes, built it in.

So all those specs went to BBN, they built the darn thing,

they delivered the switch here at UCLA, on schedule.

Eight months after they got the contract, they were to deliver this new technology,

new applications, new device.

They did it on time, on budget.

It came here, we plugged it in, and bits began to move and

forth between our timeshared machine.

And that switch on the day after Labor Day, September 2nd, 1969.

But that was just a one-node network [COUGH] Schedule was that

another one of these switches would be delivered at Stanford Research Institute,

400 miles to the north, and they would connect that to their machine.

And that happened in October, so in October we had a two node network.

My machine, my switch, another switch 400 miles away, and the SRI host.

And it wasn't one single line.

It was a gang of 4.8 kilo per second lines.

So we had to gang them together, patched it up.

So, first piece of the backbone internet.

So, now what do you do?

You have a two node network.

So, now you can do something.

So we decided, one night.

One night late in October.

Programmer, Charlie Klein and I.

Let's communicate between these two machines.

So we got a hold of Bill Duvall, they program there and we said,

let's simply log in from a terminal connected to our host, to that machine.

The idea is, these are both timesharing system.

They expect terminals to connect in, and use the services of the machine.

The big thing was sit at a terminal here, log onto your machine here, and

through this wonderful network, log on here as if you're a local user.

That's easy enough.

So, we got all set, got Charlie down at the terminal over here,

and just to be sure this worked, we had a telephone handset.

In fact, I think I've actually got the, here it is.

[LAUGH] Just happen to have it.

>> That's the telephone handset?

>> That was the telephone.

We plugged it in.

We derived a- >> Were you using and Skype?

>> Afraid not.

[LAUGH] Plugged it in.

We used a piece of the high-speed line for the phone connection.

But the interesting thing is, we were using the defunct

circuit switching technology to prove out the new packet switching technology, and

it really helped us, til we get answer.

So, Charlie typed the L, he said, you get the L?

Bill said, yep, got the L.

Typed the L, you got the L?

We're trying to do L O G, for login.

Get the O?

Got the O.

Typed the G, get the G, crash!

So, the first message ever on the network was low, as in low and behold.

Now, that's especially interesting because if you go outside this hallway,

here down under the alley, you come into another entrance to this building, and

I just discovered this about a week ago.

You walk on a platform.

And there's a mosaic of tiles down there.

And they're a strange pattern.

It turns out it's the ASCII code for lo and behold.

I have no idea who did that.

It's about a year and a half now, some very clever person put that in.

That was the first message October 29th, 1969 at 10:30 at night.

[SOUND] You're entering 1969 right now,

we're reproducing this room to look as it did and

smell and feel like it did, some forty odd years ago.

As you look over here,

you're looking at the first piece of equipment ever on the internet.

This is that first interface message processor, IMP number one, UCLA.

A Honeywell mini computer, adapted by Bolt, Beranek, and Newman, BBN.

To operate has a switch to channel the functionality.

This is the same physical four square feet,

where it served as the opening note of the Internet.

The first piece of equipment ever on the Internet.

>> And that's the actual one?

>> That's it.

I kept it for years, they tried to throw it away many times.

Most of the people had aim to toss it.

There's just the one or two left of them in the world.

But this is number one.

This is the first piece.

If you open this machine, you'll be privileged to smell it.

>> Yeah.

>> It's got an unusual odor.

It just brings you right back.

>> Yeah.

>> Emotionally, it's great.

Can't smell it today.

This is a military hardware machine, this machine was essentially

state of the art mini computer, which was adapted by BBN and

I first saw it in 1968 at one of the joint computer conference shows.

Thousands of people on a big exhibit floor.

And you see this sky hicks up here?

They had one of these machines hanging from

the ceiling swinging in the air running.

And there was a guy, big guy,

stripped to the waste, oiled skin, with a sledgehammer.

And he was going whack, whack to show that it was military.

>> He was military [LAUGH] >> And it was.

But the most important document of the internet,

most important document of the entire internet is right here.

You took who was working with me, well one of my software programmers was

John Postel, and here's his picture and he was not a hippie,

even though he appears to be.

He was the one who basically disciplined my staff to do things properly and

keep records.

He said we have to keep a record of what's going on.

So the beginning of October, basically a month after the IMP arrived,

we started keeping an IMP LOG, and this is an engineers LOG this is not

Madison Avenue these are document just scraped the old STS log.

And here we kept directed on what's going on.

And then the most important entry happened to be right here,

on October 29, 1969 at 10:30 at night, Charlie Klein the programmer

was in the room with me, made this entry, talked to SRI, host to host.

This is the only record of the very first message ever on the internet, right here.

[NOISE] We had the technology, we started making measurements,

we were the first experimental known.

So, we saw things happening, how come we have a 50 kilobit per second line.

The routing procedure either goes one way or the other, one at a time.

So how can you get more than 50 kilobits per second, between two nodes?

If there's only one path at any time?

And we say, it's obvious.

That path is on now, when it gets backed up, you change paths to this guy's

empty and it's pack backup while you send in this way make close to 100%.

>> Right.

>> So think but we could very do well, as I said and every time we did, we would BBN

and say fix it, we did this, fix it, because they wouldn't give us the code.

They kept it proprietary until opted said, we paid for that code,

you have to open it.

They did.

We saw it.

Every time we got it and it would take them six months to fix anything.

>> Right.

>> We discover a fault, this time we had the code.

We showed them how to fix it, still took six months.

One of the things I was very much interested in in the design was distribute

the control, why?

>> Right.

When I was a student of Chad, and Chad is great

working when he had a lot of things interacting, long codewords, for example.

That's when these, emerging properties arise.

So I said, I want to design large networks.

Design a large network, you can't have a single point to control.

You have to distribute it.

>> Right. >> So, what does he mean to

distribute control?

You're delegating authority to all the peers.

When office started funding principle investigators they

had the same philosophy.

Say look, you're a smart guy, here's some money, go do the thing you do best.

We're not going to sit on top of you.

Make good things happen.

So here we are.

I'm a recipient kind of money.

What do I do, then?

I've got my graduate students.

They're brilliant kids.

Look, we need to host those protocols here.

I'm going to say on top of you.

I'm going to run with it.

That is not a product mentality.

That is a research and development to create and it worked so well.

[MUSIC]

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