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Bob Metcalfe wins Turing Award

amturing.acm.org

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Re: Bob Metcalfe wins Turing Award

#161

Post by dredmorbius »

Oh yeah, Cap'n Bob:

"Linux's '60s technology, open-sores ideology won't beat W2K, but what will?" (Infoworld, June 21, 1999)

... Why do I think Linux won't kill Windows? Two reasons. The Open Source Movement's ideology is utopian balderdash. And Linux is 30-year-old technology.

The Open Source Movement reminds me of communism. Richard Stallman's Marx rants about the evils of the profit motive and multinational corporations. Linus Torvalds' Lenin laughs about world domination....

https://web.archive.org/web/19991216220752/http://www.infowo...>

Though in time he moderated his views ... slightly:

https://web.archive.org/web/20070622115025/http://www.linux....>

Re: Bob Metcalfe wins Turing Award

#162

Post by Dalewyn »

jandrese wrote: post #149
throw0101b wrote: post #112

Earlier quoted context omitted.

> Another problem is that it's CPU intensive. Are there 10GigE cards that do not do things like IP/TCP offloading at this point? Offloading dates back to (at least) 2005: * https://www.chelsio.com/independent-research-shows-10g-ether... * https://www.networkworld.com/article/2312690/tcp-offload-lif...

The other issue is that unless your computer is acting as a router or a bridge, you need to do something with that 10GB data stream. SSDs have only recently gotten fast enough to just barely support reading or writing that fast. But even if you do find one that supports writes that fast a 10GbeE card could fill an expensive 4TB drive in less than an hour. Good luck decoding JPEGs and blitting them out to a web browse…

>10GB data stream. SSDs have only recently gotten fast enough to just barely support reading or writing that fast.

10gbps (gigabits per second) is not 10GB/s (gigabytes per second).

Specifically, 10gbps is approximately 1.25GB/s or 1250MB/s.

Re: Bob Metcalfe wins Turing Award

#163

Post by Dalewyn »

BenjiWiebe wrote: post #159
Dalewyn wrote: post #157

Earlier quoted context omitted.

Yeah, it's that cost that is the problem. If I'm paying over a hundred bucks for a switch I might as well go higher and consider 10gbps options. 2.5gbps hardware need to come down to at least the $30 to $40 dollar range if they want to make any sense. Otherwise, they'll stay as niche hardware specifically for diehard enthusiasts or specific professionals only.

The NICs can be had for $20 (pretty sure I saw a $11 one the other day but can't find it right now on mobile).

The NICs are reasonable now, yes. The issue is the thing on the other side of the cable; 2.5gbps switches and routers need to come down in price.

Re: Bob Metcalfe wins Turing Award

#164

Post by ivalm »

oh_sigh wrote: post #102
lr4444lr wrote: post #56

Earlier quoted context omitted.

I respect Metcalfe a lot, but halfway through undergraduate discrete math it was pretty obvious to most people in the class even before seeing a formal proof that a fully connected graph has O(n^2) edges. I just figured that people wowed by "Metcalfe's Law" were business types who didn't any formal theory into computing.

Metcalfe's law is about network impact or value, not about connections.

Yeah, but basically it’s a statement that value scales linearly with the number of pairwise connection.

Re: Bob Metcalfe wins Turing Award

#165

Post by iptrans »

toast0 wrote: post #148
iptrans wrote: post #120

Earlier quoted context omitted.

TCP/IP offload isn’t the issue. The core problem is that the Linux kernel uses interrupts for handling packets. This limits Linux networking performance in terms of packets per second. The limit is about a million packets per second per core. For reference 10GE is about 16 million packets per second at line rate using small packets. This is why you have to use kernel bypass software in user space to get linerate perf…

You don't need an interrupt per packet, at least not with sensible NICs and OSes. Something like 10k interrupts per second is good enough, pick up a bunch of packets on each interrupt; you do lose out slightly on latency, but gain a lot of throughput. Look up 'interrupt moderation', it's not new, and most cards should support it. Professionlly, I ran dual xeon 2690v1 or v2 to 9Gbps for https download on FreeBSD; http…

Interrupt moderation only gives a modest improvement, as can be seen from the benchmarking done by Intel.

Intel would also not have gone through the effort to develop DPDK if all you had to do to achieve linerate performance would be to enable interrupt moderation.

Furthermore, quoting Gbps numbers is beside the point when the limiting factor is packets per second. It is trivial to improve Gbps numbers simply by using larger packets.

Re: Bob Metcalfe wins Turing Award

#166

Post by hinkley »

not2b wrote: post #135
caseysoftware wrote: post #24

Bob has been an active member of the Austin startup community for 10+ years and I've talked with him many times. As a EE, it was cool meeting him the first time and once I'd chatted with him a few times, I finally asked the question I'd been dying to ask: How'd you come up with "Metcalfe's Law"? Metcalfe's Law states the value of a network is proportional to the square of the number of devices of the system. When I f…

Although he made it up, there's an argument that the value goes up more than linearly. But as the network grows, every node doesn't necessarily need to talk to every other node except in rare circumstances, or they can reach each other through an intermediate point. So maybe O(n log n) would be closer.

I recall seeing an article a number of years ago that argued just that. That the network effect is nlogn. Still enough to help explain why large networks grow larger, but it also means that overcoming the incumbent is not the insurmountable wall it may seem to be. You may only need to work twice as hard to catch up, rather than orders of magnitude harder.

Re: Bob Metcalfe wins Turing Award

#167

Post by rcarmo »

Sporktacular wrote: post #22

Ethernet was always inefficient, with a crazy amount of unused legacy space reserved in an unnecessarily large header. CSMA/CD for contention was one of the ugliest medium access solutions imaginable. The coax implementation needing termination plugs was also ugly. Its advantage was cost, having had no license fees, making it suited to consumer/commercial applications driving economies of scale. It's the VHS of datac…

You forgot to put on your ATM cap :)

Re: Bob Metcalfe wins Turing Award

#168

Post by Sporktacular »

williamDafoe wrote: post #121
Sporktacular wrote: post #22

Ethernet was always inefficient, with a crazy amount of unused legacy space reserved in an unnecessarily large header. CSMA/CD for contention was one of the ugliest medium access solutions imaginable. The coax implementation needing termination plugs was also ugly. Its advantage was cost, having had no license fees, making it suited to consumer/commercial applications driving economies of scale. It's the VHS of datac…

You could not be more wrong! Efficiency and overhead are measured as a percent of frame size and 128-byte packets (X.25) or 48-byte frames (Atm) are abortions. 1500 bytes at the outset and the overhead is < 1% and < 0.2% with jumbograms (8kB). Every 802.11 standard is a superset of Ethernet and that makes DIX Ethernet the most scalable network protocol of all time!

Do you mean subset? It was first standardized as 802.3. Contention under CSMA/CD meant it was not scalable - as in it became inefficient as the segment grew. But you're right and I stand corrected in sense of the header/frame length ratio. I'd edit that first sentence if I still could.

Re: Bob Metcalfe wins Turing Award

#169

Post by xenadu02 »

Sporktacular wrote: post #158
xenadu02 wrote: post #130

Earlier quoted context omitted.

None of those things could be implemented in the 1970 or 1980s at reasonable cost so they're not actually solutions at all. Hell even making Ethernet fully switched didn't really happen until the 1990s thanks to Moore's law making the ASICs cheap enough. Without mass adoption there's no reason to invest. Look at Token Ring, Ethernet's only real competitor at scale: it quickly started to lag behind. Ethernet shipped 1…

TDMA is an extension of TDM, which goes back to the 60's. Synchronization was already solved. Variable header size could be implemented with the same preamble concept already used by Ethernet, but used to indicate the end of the header. These were not hard problems. The technology existed, the affordability would have largely depended on adoption, so it's hard to say.

We'll have to agree to disagree. Obviously TDM was known but implementing it for ethernet at a reasonable cost was just not an option at the time (in my opinion).

Re: Bob Metcalfe wins Turing Award

#170

Post by hinkley »

chasd00 wrote: post #51
caseysoftware wrote: post #24

Bob has been an active member of the Austin startup community for 10+ years and I've talked with him many times. As a EE, it was cool meeting him the first time and once I'd chatted with him a few times, I finally asked the question I'd been dying to ask: How'd you come up with "Metcalfe's Law"? Metcalfe's Law states the value of a network is proportional to the square of the number of devices of the system. When I f…

I remember trying to get NICs to work in Linux and the best advice was usually “just try the 3c509 driver”.

As a poor college student I scavenged 3c509 cards to build a computer network in an apartment I shared with two other chronic internet users.

That was right about the time someone has solved a bug with certain revisions of the card behaving differently. So suddenly the availability jumped considerably.

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