Hello again, reddit!

I’m an inventor, an innovator, an engineer, a teacher, and a National Inventors Hall of Fame inductee. I’m a jack-of-all-tech-trades, a Longhorn, a farmer, and a hiker of the wilds of Patagonia. With David R. Boggs, I created Ethernet, a technology that changed the world.

Ethernet has withstood the test of time for more than 40 years, thanks to the collective hard work of many, many individuals. Thanks to its standardization through the IEEE 802.3 Standard for Ethernet, this little invention of ours will continue to shape the future for what I hope is many more years to come.

I’m Bob Metcalfe and I enjoyed my last AMA so much, I thought I’d come back for round two. Please ask me anything!

EDIT: Just a quick note about a couple of items:

  1. Do check out the IEEE Standards Association (IEEE-SA) "Ethernet 40th Anniversary" Facebook page. Lots of cool stuff there.

  2. The winner of the IEEE-SA "I Spy Ethernet" Facebook contest is going to be featured in an animated short that will be premiered on the Anniversary Facebook page and the IEEE-SA YouTube channel. Check the Anniversary Facebook page for more details.

  3. If you want a PDF copy of my "Metcalfe's Law after 40 years of Ethernet" paper that was published in the December issue of IEEE Computer Magazine, send a PM to my reddit inbox with your email address and I will email it to you.

Comments: 1376 • Responses: 57  • Date: 

LunarWulfe718 karma

I can't thank you enough. My question is rather simple: why did you decide to call it "Ethernet?"

BobMetcalfe1428 karma

The luminiferous "ether" was an omnipresent passive medium for the propagation of electromagnetic waves.

BobMetcalfe641 karma

Be careful, bar fighting is one of my hobbies.

ImaginaryTrend430 karma

My Network II teacher talks of you as a god. His name is Dr. Bainum and I was wondering if you can ask him to give me an A in his class.

BobMetcalfe855 karma

Dear Dr. Bainum,

Although I do not know him from Adam, ImaginaryTrend strikes me as a Network II student deserving of an A.

/Bob Metcalfe, UTAustin Professor of Innovation

anon1821387 karma

Ethernet is AWESOME


BobMetcalfe313 karma

You are welcome.

ribsteak289 karma

What is the next big interface/protocol according to you?

BobMetcalfe610 karma

Automotive. Cars will have three networks. (1) Within the car. (2) From the car up to the Internet. And (3) among cars. IEEE 802 is ramping up for these standards now, I hope.

BobMetcalfe288 karma

Gotta go. I'll be back. Thanks!

BookPirates287 karma

What gives you the right?

BobMetcalfe256 karma

Right to do what?

BookPirates428 karma

Hm, I'm not sure.. That's just my go-to AMA question. No one ever answers.. Uh.. The right to change the world in such a positive way? How dare you!

BobMetcalfe443 karma

Am still trying to please my parents, who are in Heaven rooting for me.

oldendude275 karma

We are cat people. We like having two of them at a time. We try to keep them inside, but unfortunately they escape occasionally, and sometimes they get run over, so we are now on our fourth and fifth cats. It was my turn to name the newest cat member of our family, and I chose the name Cat5.

Thank you.

BobMetcalfe237 karma

Maybe you can tie them up better with Cat5?

Artvandelay1211 karma

Hi Bob, thanks for coming to reddit. I hate to be this guy, because you've clearly done so much to develop technology that drives modern society. Not to mention no one should be held by predictions made decades earlier or else we'd all look stupid, but I'm fascinated by how societies try and see how the world is changing. You once made a prediction that wireless networking would die out in the 1990s. Can you explain why it seemed at the time that this was this was going to happen and when you realized that your prediction may have needed adjustment? Bonus question: in your opinion, why are we always so terrible at predicting the future?

BobMetcalfe346 karma

Wireless DID die out in the 1990s, when the radios were bigger than the PCs, but then came roaring back. Ethernet followed on Alohanet circa 1979, and so now it's come full circle to WiFi. We are pretty good a predicting the future, but not very good at getting the timing right.

Artvandelay197 karma

Thanks for answering, that's an interesting take. Do you know of any specific example in history where a prediction was very inaccurate for the period but ultimately came to fruition?

BobMetcalfe157 karma

Took a long time for interactive time-shared minicomputers to replace batch-processing mainframes. Then is took a long time for The Year of the LAN to happen -- I kept predicting it year after year.

Profano196 karma

Thanks for all my lan parties, my Lord.

BobMetcalfe274 karma

I have never been to a LAN party. Am looking forward.

LeavesItHanging182 karma

Thank you.

BobMetcalfe167 karma

You're welcome, AMA.

Meltingteeth170 karma

Bob, I use black. CAT5 in my systems. Opinions?

BobMetcalfe737 karma

Ethernet cables should be yellow. And that's that.

Kenjiee151 karma

It's thanks to you that I don't have to install token ring. Thanks!!!!

BobMetcalfe205 karma

I only wish I had been a better salesman of Ethernet to IBM in 1980 -- would have saved us decades of Token Ring. You are welcome.

carrollr142 karma

When designing Ethernet, did you ever consider a backpressure mechanism ala Frame Relay's BECN/FECN?

How do you feel about the current state of play (100G coming too late + too expensive, the approach of the IEEE being that 40Gbit was a good intermediary step) in the ethernet field?

If you were re-designing Ethernet with your current knowledge, what would you take out of the protocol?

Also - thank you for giving me a career :)

BobMetcalfe154 karma

Ethernet had back-off for flow/congestion control, which then migrated up into TCP/IP also. Got the idea from the Santa Monica Freeway traffic lights.

Moves from 10G to 40G to 100G to 400G to TE are part of the Ethernet ethic, which says built it and they will come (eventually).

login22882259 karma

Why 40 and 400 instead of 50 and 500?

BobMetcalfe142 karma

Ethernet speeds tended to increase 10X. Telephony speeds tended to increase 4X. At 10Gbps or so they converged and the two industries had to reconsider their improvement steps. I'm up for 1Tbps next.

iiDrushii128 karma

Hey Bob! I've got an odd question if you don't mind...

Like most of us here, have you ever tried to plug an Ethernet cable into its respective port just to realize the device you're plugging it into only has a phone jack?

BobMetcalfe226 karma

Cannot begin to tell you how many times I've tried to plug Ethernet into the wrong socket -- today even, in this hotel room. What is amazing, actually, is how many times it works!

arabianbear117 karma

What's your view on chipotle charging extra for guacamole?

BobMetcalfe258 karma

Pay it.

I_wesley12598 karma

What initially compelled you to develop Ethernet?

BobMetcalfe182 karma

At Xerox Parc we were, if you can imagine it, putting a personal computer on every desk. I got the job of extending the Internet into our buildings to the PCs so they could print and access the Internet (then Arpanet). Lucky me.

BobMetcalfe85 karma

Have just revisited "Metcalfe's Law after 40 years of Ethernet." The Law remains V~N2. But I have put the Law in context using a "netoid" s-curve function and modeled the first 10 years of Facebook membership and revenue. The paper appears in the December issue of IEEE Computer. If you would like a free PDF of the paper, please send a PM to my reddit inbox with your email address.

ribsteak74 karma

Hey Bob I am a big fan ever since I learned about your work while I was studying to become an engineer. One thing I havent quite figured out is why you dislike open sources(sores) software? Would love to know the exact reasons behind your dislike of that approach to software development

BobMetcalfe167 karma

OK, the question was, which way to deliver a modern operating system? The advanced American software company (eg Microsoft) or a non-profit group of open-source volunteers. This is a false dichotomy. I attacked Windows at the same time as open sores. Nether has delivered on that new OS I'm looking for. Just more old time-sharing systems.

LeavesItHanging73 karma

What's your favourite internet pun?

BobMetcalfe237 karma

Internet evangelist Vint Cerf goes around saying "IP on everything."

thepobv69 karma

It's weird I'm sitting here in a Computer Networks class browsing reddit and I saw this AMA it's like a sign I should start paying attention to class or something.

Can you explain the OSI layer model? that's what the prof is doing but I'm not listening... I'll read it if you answer though.

BobMetcalfe104 karma

The OSI model is a way of organizing and dividing the functions of a network, especially the Internet. I have lived a rich full life at layers 1 and 2 and sometimes 3 and 4 of the OSI model. All the fun gets had at layer 7.

synapticallyplastic60 karma


BobMetcalfe94 karma

Protocol design is an art. It's important to leave things open for unexpected uses -- generality. TCP/IP/Ethernet were invented in 1973, and along came the web in 1989. Whoa! Also, mutual suspicion among protocol parties adds robustness.

bogseywogsey52 karma

As an IT professional, I feel I have to chime in because I'll never forget this:

OrangeWhite, Orange, GreenWhite, Blue, Bluewhite, Green, BrownWhite, Brown

still one of my favorite parts of my job.

Did you ever expect Ethernet (at least the physical media) to be installed in homes as much as businesses?

BobMetcalfe41 karma

Yes, I did, but not until 1982, when we started selling Ethernet for the new IBM PC, many of which were going into homes with more than one.

Otto_Maller50 karma

Hello Bob - we met many, many years ago when I was a lowly account executive at Franson & Associates and you were the CTO at 3Com. We were your PR agency. I was always impressed that although you basically invented the company, you handed the reigns to Eric Benhamou, recognizing your strengths and his. That's the non-ego move that impresses me to this day. Later, while earning my MBA, you were held up as an example of a successful strategy vs. the engineer who develops the technology but can't run the company. Nicely done sir. Just wanted to pass that along.

BobMetcalfe66 karma

Thanks. Twice, the Board of Directors which I assembled as Chairman of 3Com chose somebody else as CEO. In 1982, Bill Krause took over from me; in 1989, Eric Benhamou took over from Bill. In retrospect, my board was right both times. When founding 3Com, I decided early that its success was more important than my running it.

atarifan260045 karma

What was your favorite thing about PARC? That sounds like such an amazing place. Do you feel that the the current big companies like Google and Apple have R&D environments on par with what Xerox was accomplishing at the time?

PARC still feels like a futuristic wonderland to me.

Thanks for ethernet, by the way. I still love your original drawing.

BobMetcalfe94 karma

The only companies that can afford research are monopolies, which I do not think are worth it, and they are the least motivated to take their innovations into the markets they dominate. So, I favor doing America's research at our 100+ research universities. Google is very cool R&D, like Parc was, only way bigger. Apple seems to do only D, but they do it so well and innovate "openly."

microseconds44 karma

How far did you envision Ethernet would endure? Did you expect to see the evolution of 10M to 100M, through 100G and coming before too long 400G?

Did you consider Ethernet's applicability as a possible WAN medium way back when?

BobMetcalfe52 karma

Ethernet has surprised a lot of people, especially me. Questions like yours depend on the semantics -- what you think Ethernet is. Ethernet in the WAN (killing SONET!) and Carrier Ethernet were big surprises to me. Look at Carrier Ethernet, now $100B/year.

jnewmano41 karma


What are your thoughts on connecting little widgets and devices to the internet? Wireless or hard-wired? Does my toaster really need to be connected to the internet?

BobMetcalfe76 karma

Yes, your toaster needs to be connected to the Internet. Emerging networks are both wireless and wired (fibered). For example, LTE packets go right onto fibered Ethernets -- LTE = Leads To Ethernet.

Spacish35 karma

I don't have a question, just passing by to thank you for your work. You deserve more credit!

BobMetcalfe98 karma

Actually, for Ethernet, I get more credit that I deserve, but that's the way life seems to go. Dave Boggs, Butler Lampson, Chuck Thacker, Tat Lam, John Shoch, David Liddle and 100s more -- we tried to share the blame at the Ethernet 40th event at the Computer History Museum.

RembrandtEpsilon34 karma

You're my hero man. I constantly talk about the structure of data and how we send it over vasts distances.

A few questions:
Is it possible to implement ethernet on a toaster?

Have you seen the HDMI with ethernet on them? What do you make of that? What is the next big physical medium to tackle the use of ethernet?

I always romanticize what it was like back in the day creating the technology we currrently utilize daily. What was it like working with Xerox and ALOHAnet? What is the most romantic memory you have the tech industry?

Thanks for your time here today. You're a real internet hero.

BobMetcalfe80 karma

Toasters will be networked for sure, the question is, what about slices of bread? Every slice should have an IPv6 node number, no?

Spent a month in Hawaii studying Alohanet isn early 1970s -- recommend that. Xerox Parc was heaven on Earth -- did not own an alarm clock.

OkayKappa30 karma

I have a Computer Networks exam tomorrow. If the creator of Ethernet would wish me luck, it couldn't go wrong, could it?

BobMetcalfe53 karma

Good luck on your Computer Networks exam tomorrow. Get sleep, drink lots of water, have fun.

draibop30 karma

bob, i love you! if you had to fight one inventor from history who would you choose and why

also side question do you think you could win in a fight against Bj novak?

BobMetcalfe64 karma

Careful, bar fighting is one of my hobbies.

Knightsavior28 karma

Am I allowed to worship you for your invention?

BobMetcalfe114 karma

You may worship me, but only if it causes you to learn, to work, to communicate, to team up, to achieve great things yourself. I hope to serve you as a provocation.

koztown26 karma

Hey Bob!

In a recent interview with Bob Krause he tells a tale about how Steve Jobs influenced the development of 10BaseT (as opposed to the coax and vampire taps before).

Is Bob right? Can you tell anything else about how we got from coax to RJ45 connectors?

BobMetcalfe51 karma

Bill Krause's story about Steve Jobs (RIP) complaining about Ethernet cables is certainly true. Steve would not shut up about it. So, he got AppleTalk developed, which was cheaper and slower and less cable ridden and non-standard. Took a long time to talk Steve into Ethernet, but by then it was quite different. Still he was unhappy with all the wires, and pushed for WiFi.

[deleted]25 karma

Was your invention intended to be as huge as it was?

BobMetcalfe101 karma

Depends on which year. At the start, in 1973, the goal was mainly to print on our new laser printer. By 1980, world domination was the goal.

KYLETS823 karma

Favorite sandwich?

BobMetcalfe44 karma

Pastrami. I'm a health nut.

IvyMike23 karma


First let me say thank you. I used to work at a network test equipment company, and knowledge of ethernet is so entrenched that it's kind of hard to believe there was a time that there wasn't ethernet. It's like you invented arithmetic.

Now on to my ridiculous question: I have a hazy memory of reading an article that you used to drink copious quantities of diet soda every day... like 24 cans. I can't find a reference to this anywhere on line, so it's likely that it's the result of my imperfect memory, but still, I have to ask: is this true?

BobMetcalfe60 karma

Worse! I used to drink a case of (classic) Coke everyday, which is not good for anybody. Weight gain. Mania. Switched to diet, but now just avoid soft drinks, especially carbonated sugar water. Regular water is good for you.

NateThomas197923 karma

What is your current stance on net neutrality and how do you propose to fix the balance between access and proprietary content?

Also... 100 cat5 cables or 1 cat500 cable?

BobMetcalfe41 karma

Am neutral on net neutrality. Way too complicated. Busy elsewhere.

what_did_you_eat22 karma

Hey Bob! We make our interns make ethernet cables all the time!

What did you eat today? Do you remember what you ate the day you finally got Ethernet to work?

BobMetcalfe30 karma

Today, so far, a scone. Day Ethernet first worked, Hunan.

andrewhohoho19 karma

Will I ever catch you on 6th street one of these weekends?

BobMetcalfe34 karma

I am on 6th street every day. Live across from Whole Foods Market HQ. Or do you mean the bars further east?

penncage19 karma

For the future of humanity - excepting Ethernet and asteroid mining - what technology do you most eagerly await?

BobMetcalfe57 karma

Excepting Ethernet and asteroid mining, hm, I am eagerly awaiting the Internet's coming disruption of education -- MOOCs and their descendants. Also, healthcare, more personal and preventative, thanks to networking.

wheeler143218 karma

How should the Internet be governed? In particular, what should the role of government be? thanks!

BobMetcalfe45 karma

Governments are running amok these days, and I'm worried.

mickeypisa18 karma

Did your invention make you wildly rich? :)

BobMetcalfe80 karma

Selling, not inventing, Ethernet left me with a fortune which is a significant fraction of a milliGates.

chocki30517 karma

Where you involved with making Gigabit ethernet? And do they still belong to you? And can I please use it for umm... Science, ya science.

BobMetcalfe29 karma

No. No. Yes.

woprdotmil17 karma


BobMetcalfe32 karma

I bet there are differences of signal propagation among cable colors, but they are all close to the speed of light, so the differences don't generally show up in network performance. You are pulling my leg.

Vonhohenheim16 karma

I take it you don't get a penny for every Ethernet cable sold?

BobMetcalfe55 karma

Used to get $1 per port, but now only a penny per packet. Business model innovation.

insufficient_funds16 karma

Holy hell, I almost feel like your level of knowledge and topic-area will be way over the heads of the average IAmA suscriber..

My question: Why Yellow?

BobMetcalfe44 karma

Yellow was the color we chose at Xerox Parc to distinguish Ethernet cables in the ceiling from all of the others. See no reason to change now.

fonzie58815 karma

How did you feel about TCP/IP being chosen over OSI as the de-facto communications protocol on the Internet?

BobMetcalfe24 karma

TCP/IP and OIS and XNS and DECnet and Wangnet and ... were all pretty much equivalent. What let TCP/IP win was the persistence of Vint Cerf and the interoperability ethic of TCP/IP (not simply conformance). Also, the use of universities and startups to advance TCP/IP rather than incumbent monopolies.

drake072715 karma

You probably met Edsger Dijkstra being a Longhorn and all. Do you have any interesting stories about him?

BobMetcalfe21 karma

Before my time.

yt914 karma

Hello Bob, Any thoughts on recording and transmitting smells, scents, odors via ethernet based robots? Tia. See you on the water in Owls Head this summer.

BobMetcalfe22 karma

Only a question of time before we have a standard for digitizing smells.

Am looking forward to the ocean smells of Owls Head this coming Summer.

mcgarnicle2113 karma

SDN, exciting thing or marketing BS?

BobMetcalfe26 karma

SDN will change names several more times, but something akin to it, say network virtualization, is a coming thing, like for processors and storage.

MysticalTurban11 karma

Are you working on any new inventions now?

BobMetcalfe21 karma

Am working on inventions related to the process of startups out of research universities. They make the world go round, but not well enough yet.

RAyerInk9 karma

Ahoy Bob, what are your thoughts on security issues for all of our connectedness. It seems like it will just be a constant race between the 'good' guys and the hackers only with more at stake, like moving vehicles and the inner workings of our homes. What say you?

BobMetcalfe25 karma

Internet security will never be a solved thing, but we can do a lot better than now. Ethernet makes no contribution, assuming the higher levels of protocol have it handled, which they do not.

darknyan8 karma

What do you think is the best approach to deploying internet to far-reaching places of the world?

BobMetcalfe22 karma

That's happening. Best approach is proliferating Free Enterprise.

NoobFace7 karma


BobMetcalfe19 karma

Mine: RFC #89, January 1971.