

Speed matters: how Ethernet went from 3Mbps to 100Gbps... and beyond - mukyu
http://arstechnica.com/gadgets/news/2011/07/ethernet-how-does-it-work.ars

======
ghshephard
I always get a bit nervous about the technical accuracy of an article like
this when stuff like the following gets past both the author and editors:

    
    
       Fast Ethernet uses the same CDMA/CD as Ethernet
    

That should be CSMA/CD. They had it right earlier and later on, not sure how
this reference got by them, Ars is usually pretty good about nailing this
stuff. The article itself is actually pretty darn good.

Also,

    
    
       On the other hand, in 1975 few people would have guessed 
       that today's students would go to class carrying 
       affordable computers with 10Gbps ports.
    

I'm wondering what they are referring to here - what portable systems have
10Gbps ports?

On a related note, several top tier network engineers I work with who do a lot
of work at Layer3 (Writing Mesh routing protocols) - say if they could have
one, and only one book for the rest of their life, it would be Radia Perlman's
"Interconnections, 2nd Edition." I'll attest that some chapters have captured
my attention for months. :-)

~~~
jolan
> Fast Ethernet uses the same CDMA/CD as Ethernet

> That should be CSMA/CD. They had it right earlier and later on, not sure how
> this reference got by them

It's a one letter typo. The keys are adjacent on the keyboard. Enhance your
calm.

~~~
ghshephard
My angst with the typo, is that I work on CDMA and GSM networks all day. Now,
I know that it really should mean CSMA, but can you imagine someone from a
different context reading this and wondering how CDMA and Ethernet tie
together?

Regardless - less of an issue on a blog post, but Ars normally sets a really
high bar for copy editing - odd they let that one get by them.

------
shalmanese
"Think about it: is there any other 30-year-old technology still present in
current computers? 300 baud modems? 500 ns memory? Daisy wheel printers?"

IBM Model M keyboards.

~~~
baddox
Not to mention tons of ubiquitous algorithms.

------
SpacemanSpiff
my favorite part of the article:

Algorhyme

    
    
            I think that I shall never see
            a graph more lovely than a tree.
            A tree whose crucial property
            is loop-free connectivity.
            A tree that must be sure to span
            so packet can reach every LAN.
            First, the root must be selected.
            By ID, it is elected.
            Least-cost paths from root are traced.
            In the tree, these paths are placed.
            A mesh is made by folks like me,
            then bridges find a spanning tree.
    
                             Radia Perlman

~~~
gruseom
I was liking it too, until the abrupt meter change in line 7. People almost
invariably mess up the meter when writing this kind of verse. It's a hallmark
of tone-deafness, or whatever the equivalent is for rhythym. For anyone who is
paying attention, it spoils the effect.

But then I noticed something surprising. Yes, the meter changes abruptly from
iambic to trochaic at line 7, i.e. the stress goes from even syllables ("I
_think_ that _I_ shall _nev_ er _see_ ") to odd ones (" _First_ the _root_
must _be_ sel _ec_ ted.") However, the shift is executed perfectly: the meter
is a steadfast trochee for four lines and then reverts to iamb for the final
couplet.

Accident? I doubt it. Each of the four trochaic lines is a complete sentence.
The iambic lines all have exactly one sentence per two lines. No, this is the
rare case where the writer knows exactly what she is doing. Bravo Radia
Perlman!

~~~
elwin
Well spotted. Also, the four trochaic lines list the steps of the tree-
building process, and the iambic couplets explain the purpose of it all. She's
using meter to reflect a semantic division.

------
Dylan16807
While the article says that deciding if a crossover cable is needed is still a
problem today, in my experience devices figure out what cable they have
attached and just work.

------
iwwr
When will we see consumer devices rated at above 1gigabit?

~~~
absconditus
Why do consumers need such a thing?

~~~
Groxx
There are a few places you can get gigabit fiber, even excluding Google's
offering.

~~~
absconditus
How does this explain the need for greater than gigabit networking?

