Re: Hubs on a NIC (was:Re: what about 48 bits?)

[Roland Perry]

In article , 
Steven Bellovin  writes

Remember, it was this strange time when people were uncertain about how
networks were going to evolve, and what the next thing would be, and
even then, 10baseT was being deployed over Cat3 (sometimes recycled/
repurposed), so any sort of "enabling" gadget such as these cards had a
tendency to be abused in various ways.


Right -- the wire and pin assignments for 10BaseT and 100BaseT were
designed to permit sharing the cable between Ethernet and phone.


I wired a new-build house (of mine) like that in 1995. The CAT5 cable 
was expensive enough that it made sense to share. And it worked. The 
bigger challenge was getting Internet to the house, not round the house.


Ten years later, both voice and data would probably have been better 
done by wireless (DECT and wifi respectively).

--
Roland Perry

Re: what about 48 bits?

[Roland Perry]

In article <201004071118.o37bivk1022...@aurora.sol.net>, Joe Greco 
 writes



Unfortunately, power-cycling crashed PC's is (was?) pretty common, and
many users are (were?) also trained to shut off PC's when done, so here
you've introduced something that is by-design going to fail periodically.


OK, I agree that fitting a PC-powered hub into a client PC isn't the 
best decision in the world. But losing one segment of a 10Base-T LAN 
(which was the technology I used) is not the end of the world, and I 
took the precaution of installing the hub in my server.


Despite these potential operational banana skins, it was still a product 
that tipped me irrevocably into the world of Ethernet (having earlier 
toyed with pale imitations).

--
Roland Perry

Re: what about 48 bits?

[Vince Fuller]

> To be fair, everything for a vax was somewhat pricey.  And slow.
> 
> On an even more unrelated note, does anyone remember the day that 
> CMU-TEK tcp/ip stopped working some time in the early 1990s?  That was a 
> load of fun.

What made it stop working?

I was the guy to blame for the IP/TCP/UDP parts of "CMU-TEK" and had long
since left CMU by the mid-90s. Dale Moore (still at CMU last time I checked)
did the applications.

--Vince

Re: Hubs on a NIC (was:Re: what about 48 bits?)

[Joe Greco]

> When I had the need to wire a building around 1987, I opted for the 
> multiport 10Base5 repeaters that DEC made -- they were called DELUAs, 
> I think.  I'd had quite enough of distributed single points of failure,
> thank you.

Think those were something else;

DEMPR = Digital Ethernet Multi Port Repeater
DELNI = Digital Ethernet Local Network Interconnect ("hub")

Threw some away a few years ago.

> Hey, I had that in my house on my 100BaseT network, till I upgraded 
> to gigE and had to give in and buy another switch.  (Sigh -- home 
> network configurations of NANOGers.  I'm contemplating putting in 
> VLANs now...)

VLAN's == fun

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

Re: Hubs on a NIC (was:Re: what about 48 bits?)

[Steven Bellovin]

On Apr 7, 2010, at 11:03 16AM, Joe Greco wrote:

>> On Wednesday 07 April 2010 07:18:57 am Joe Greco wrote:
>>> To me, this is a Dilbert-class engineering failure.  I would imagine that
>>> if you could implement a hub on the network card, the same chip(s) would
>>> work in an external tin can with a separate power supply.  Designing a
>>> product that actually exhibits a worse failure mode than 10base2 is ...
>>> strange to me.
>> 
>> I have in my gear museum a fairly large box with a couple of this type of 
>> 'hub 
>> on a card' installed.  And in this particular case, it made perfect sense, 
>> as 
>> the box is an Evergreen Systems CAPserver, and has 16 486 single-board 
>> computers tied to two 8-port hub cards (two ports on each modular plug, 
>> too), 
>> withwait for it... a 10Base-2 uplink.  These were used mostly for remote 
>> network access and remote desktop access.
>> 
>> If you want more data on this old and odd box, see 
>> http://www.bomara.com/Eversys/capserver2300.htm
>> 
>> I can see a hub card being useful in an old NetWare server setting, though, 
>> since if the server went down you might as well not have a network in the 
>> first 
>> place, in that use case.
> 
> Certainly.  I can come up with a bunch of reasonable-use scenarios too,
> but most of the people here will have run into that awful situation where
> a product is used in a manner that isn't "Recommended".
> 
> In this case, I know that some of these cards were marketed in the same
> manner that workgroup hubs/switches are marketed; you would daisy-chain
> these stupid things so that your PC would feed the cubes right around you
> and then have an uplink and downlink a few cubes to the next "hub".

When I had the need to wire a building around 1987, I opted for the multiport 
10Base5 repeaters that DEC made -- they were called DELUAs, I think.  I'd had 
quite enough of distributed single points of failure, thank you.
> 
> Remember, it was this strange time when people were uncertain about how 
> networks were going to evolve, and what the next thing would be, and
> even then, 10baseT was being deployed over Cat3 (sometimes recycled/
> repurposed), so any sort of "enabling" gadget such as these cards had a
> tendency to be abused in various ways.

Right -- the wire and pin assignments for 10BaseT and 100BaseT were designed to 
permit sharing the cable between Ethernet and phone.
> 
> Two ports on each modular plug, though (shudder)  ;-)
> 

Hey, I had that in my house on my 100BaseT network, till I upgraded to gigE and 
had to give in and buy another switch.  (Sigh -- home network configurations of 
NANOGers.  I'm contemplating putting in VLANs now...)


--Steve Bellovin, http://www.cs.columbia.edu/~smb

Re: what about 48 bits?

[Jeroen van Aart]

Nick Hilliard wrote:
On an even more unrelated note, does anyone remember the day that 
CMU-TEK tcp/ip stopped working some time in the early 1990s?  That was a 
load of fun.


I remember a satellite taking care of trans-Atlantic internet traffic 
going down in the mid 90s causing 30 minute lags on irc, if that counts. :-)

Re: Re: what about 48 bits?

[Jeff Kell]

That would be the AMP quick connect kit.  Been there, done that, got the scars 
and war stories too.

The most notable was that the "drops" from the actual coax down to the 
end-stations were of a non-trivial length, and the actual length added to your 
coax segment was double that (due to the loop out to the end-station).  We had 
several cases of segments getting "too long" unexpectedly, and some green techs 
hooking up 3-4 drops in their new office areas at the same time (adding ~100' 
to your run)...

Jeff

-Original Message-
From: Joe Greco 

There were several proprietary solutions to the 10base2 conundrum,
I can't remember the name of the one I was most familiar with, but it
eliminated all that stuff by using a molded cable that had a BNC on
one end, contained dual RG cables inside a heavy jacket, and a funky
molded plug on the end.  The plug would connect to a socket through
which a 10base2 segment ran, and inserting the plug would open a 
switch that shorted the conductors, and then the cable would form
the link to re-complete the segment.

Re: what about 48 bits?

[Stefan Bethke]

Am 07.04.2010 um 17:47 schrieb Joe Greco:

> There were several proprietary solutions to the 10base2 conundrum,
> I can't remember the name of the one I was most familiar with, but it
> eliminated all that stuff by using a molded cable that had a BNC on
> one end, contained dual RG cables inside a heavy jacket, and a funky
> molded plug on the end.

One system popular in Germany at the time used a modified German phone plug 
("TAE"), and the resulting system was marketed as "EAD" or Ethernet Anschluss 
Dose.  The coax was way too heavy and stiff for the small plug, and would 
regularly unseat the connector.  Since the phone plug was never designed to 
have a defined impedance, any run longer than about 50 meters for the segment 
was hit and miss.

http://en.wikipedia.org/wiki/EAD-socket


Stefan

-- 
Stefan BethkeFon +49 151 14070811

Re: what about 48 bits?

[Joe Greco]

> I thought that was just me.  My first IT job was developing credit-
> card systems on VAXen.  We had the office flood-wired with 10base2 
> in one long bus - at locations where there wasn't a PC yet, there 
> was just a faceplace with two BNC connectors, and a tiny patch 
> lead between them.
> 
> To install a new PC, you had to have a length of co-ax long enough 
> to go from the faceplate to the desk and back, with a T-piece in 
> the middle.  Installation involved whipping out the short patch 
> lead and re-connecting both ends of the longer one before things 
> elsewhere declared the network as broken and started shutting down 
> somewhat ungracefully.  This was best done as a two-man job, but 
> we did get it down to quite an art.
> 
> Nice to know after all this time that someone else was playing the
> same silly game...

There were several proprietary solutions to the 10base2 conundrum,
I can't remember the name of the one I was most familiar with, but it
eliminated all that stuff by using a molded cable that had a BNC on
one end, contained dual RG cables inside a heavy jacket, and a funky
molded plug on the end.  The plug would connect to a socket through
which a 10base2 segment ran, and inserting the plug would open a 
switch that shorted the conductors, and then the cable would form 
the link to re-complete the segment.

Much fun was to be had:

1) Plugging in a network cable partway might break the circuit without
   also establishing the new path,

2) Sometimes the sockets would get fouled and locating the problem was
   a royal pain,

3) Because the system was meant to be simple enough for users to use,
   users would sometimes plug in too many of these cables, extending
   the maximum length of the network beyond standard,

4) Also because users could be involved, when one of them did something
   to the network, they would either not realize it or not own up to it,
   further adding to the debugging fun.

When it worked, it worked great.  Which was most of the time.

I used to remember what the darn things were called...

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

Re: what about 48 bits?

[Tim Franklin]

> This reminds of me of the failure-mode-within-a-failure-mode of 10b2
> with vaxstation2000's using vms's vaxcluster software. Unplugging the
> 10b2 gave you a window of about 10 seconds before one by one every
> vaxstation2000 would bugcheck. I was always rather astonished that
> nobody at DEC either noticed it, or thought it was a very big deal
> because the bug survived a long time.

I thought that was just me.  My first IT job was developing credit-card systems 
on VAXen.  We had the office flood-wired with 10base2 in one long bus - at 
locations where there wasn't a PC yet, there was just a faceplace with two BNC 
connectors, and a tiny patch lead between them.

To install a new PC, you had to have a length of co-ax long enough to go from 
the faceplate to the desk and back, with a T-piece in the middle.  Installation 
involved whipping out the short patch lead and re-connecting both ends of the 
longer one before things elsewhere declared the network as broken and started 
shutting down somewhat ungracefully.  This was best done as a two-man job, but 
we did get it down to quite an art.

Nice to know after all this time that someone else was playing the same silly 
game...

Regards,
Tim.

Re: Hubs on a NIC (was:Re: what about 48 bits?)

[Joe Greco]

> On Wednesday 07 April 2010 07:18:57 am Joe Greco wrote:
> > To me, this is a Dilbert-class engineering failure.  I would imagine that
> > if you could implement a hub on the network card, the same chip(s) would
> > work in an external tin can with a separate power supply.  Designing a
> > product that actually exhibits a worse failure mode than 10base2 is ...
> > strange to me.
> 
> I have in my gear museum a fairly large box with a couple of this type of 
> 'hub 
> on a card' installed.  And in this particular case, it made perfect sense, as 
> the box is an Evergreen Systems CAPserver, and has 16 486 single-board 
> computers tied to two 8-port hub cards (two ports on each modular plug, too), 
> withwait for it... a 10Base-2 uplink.  These were used mostly for remote 
> network access and remote desktop access.
> 
> If you want more data on this old and odd box, see 
> http://www.bomara.com/Eversys/capserver2300.htm
> 
> I can see a hub card being useful in an old NetWare server setting, though, 
> since if the server went down you might as well not have a network in the 
> first 
> place, in that use case.

Certainly.  I can come up with a bunch of reasonable-use scenarios too,
but most of the people here will have run into that awful situation where
a product is used in a manner that isn't "Recommended".

In this case, I know that some of these cards were marketed in the same
manner that workgroup hubs/switches are marketed; you would daisy-chain
these stupid things so that your PC would feed the cubes right around you
and then have an uplink and downlink a few cubes to the next "hub".

Remember, it was this strange time when people were uncertain about how 
networks were going to evolve, and what the next thing would be, and
even then, 10baseT was being deployed over Cat3 (sometimes recycled/
repurposed), so any sort of "enabling" gadget such as these cards had a
tendency to be abused in various ways.

Two ports on each modular plug, though (shudder)  ;-)

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

Re: what about 48 bits?

[Michael Thomas]

On 04/07/2010 04:18 AM, Joe Greco wrote:

To me, this is a Dilbert-class engineering failure.  I would imagine that
if you could implement a hub on the network card, the same chip(s) would
work in an external tin can with a separate power supply.  Designing a
product that actually exhibits a worse failure mode than 10base2 is ...
strange to me.


This reminds of me of the failure-mode-within-a-failure-mode of 10b2 with
vaxstation2000's using vms's vaxcluster software. Unplugging the 10b2 gave
you a window of about 10 seconds before one by one every vaxstation2000
would bugcheck. I was always rather astonished that nobody at DEC either
noticed it, or thought it was a very big deal because the bug survived a
long time.

Mike

Re: what about 48 bits?

[Michael Thomas]

On 04/07/2010 04:18 AM, Joe Greco wrote:

To me, this is a Dilbert-class engineering failure.  I would imagine that
if you could implement a hub on the network card, the same chip(s) would
work in an external tin can with a separate power supply.  Designing a
product that actually exhibits a worse failure mode than 10base2 is ...
strange to me.


This reminds of me of the failure-mode-within-a-failure-mode of 10b2 with
vaxstation2000's using vms's vaxcluster software. Unplugging the 10b2 gave
you a window of about 10 seconds before one by one every vaxstation2000
would bugcheck. I was always rather astonished that nobody at DEC either
noticed it, or thought it was a very big deal because the bug survived a
long time.

Mike

Hubs on a NIC (was:Re: what about 48 bits?)

[Lamar Owen]

On Wednesday 07 April 2010 07:18:57 am Joe Greco wrote:
> To me, this is a Dilbert-class engineering failure.  I would imagine that
> if you could implement a hub on the network card, the same chip(s) would
> work in an external tin can with a separate power supply.  Designing a
> product that actually exhibits a worse failure mode than 10base2 is ...
> strange to me.

I have in my gear museum a fairly large box with a couple of this type of 'hub 
on a card' installed.  And in this particular case, it made perfect sense, as 
the box is an Evergreen Systems CAPserver, and has 16 486 single-board 
computers tied to two 8-port hub cards (two ports on each modular plug, too), 
withwait for it... a 10Base-2 uplink.  These were used mostly for remote 
network access and remote desktop access.

If you want more data on this old and odd box, see 
http://www.bomara.com/Eversys/capserver2300.htm

I can see a hub card being useful in an old NetWare server setting, though, 
since if the server went down you might as well not have a network in the first 
place, in that use case.

Re: what about 48 bits?

[John Kristoff]

On Tue, 06 Apr 2010 23:02:12 -0400
joel jaeggli  wrote:

> > Ah, but what _caused_ Ethernet to become ubiquitous, given the
> > price was initially comparable?
> 
> Early standardization.

In one of my other favorite books, Gigabit Ethernet, Rich Seifert says:

  "[...] IBM was the only computer *systems* manufacturer actively
  promoting a Token Ring-based strategy.  Ultimately, the reason we
  build networks is to attach the computers that supports the users'
  applications.  Network equipment vendors provide products to support
  the interconnection of the computers, but the network is the means,
  not the end.  Ethernet had the necessary broad support from many
  computer systems manufacturers from the very beginning, including not
  only the original DIX consortium, but also major players like Sun
  Microsystems, Hewlett-Packard, and dozens of others."

John

Re: what about 48 bits?

[Joe Greco]

> In article <201004071023.o37antww018...@aurora.sol.net>, Joe Greco 
>  writes
> 
> >>interoperability and backwards  compatibility were the tipping points.
> >
> >Ah, yes, backwards compatibility: implementing the fantastic feature of
> >breaking the network...
> 
> By "backwards compatibility" I mean the ability to use the new LAN from 
> a laptop that didn't have an Ethernet connection built in, and didn't 
> have an optional [proprietary] internal Ethernet card available either.

There are a lot of things to target with the term, I was picking
conveniently.  :-)

> >we all remember the fun of what happened when
> >someone incorrectly unhooked a 10base2 network segment; D-Link managed
> >to one-up that on the theoretically more-robust 10baseT/UTP by
> >introducing a card that'd break your network when you powered off the
> >attached PC.
> 
> That tale of woe doesn't really sound like it's the fault of backwards 
> compatibility.

No, but I remember network people talking gleefully about the benefits of
10baseT (and come on - it has lots), and how it fixed the "someone needed
to move a PC and disconnected the cables from the T rather than the T
from the NIC" problem...  and along came D-Link (and some other vendors
I think) with the brilliant idea of a host-integrated hub.

Now, remember, some network guys walked around with new-in-bag BNC T's in
their pocket because they'd run across someone who disappeared a T every
month or two, and there's great power in turning your back, twiddling for
a few seconds, and then being able to holler "Network's back up!"...

Unfortunately, power-cycling crashed PC's is (was?) pretty common, and 
many users are (were?) also trained to shut off PC's when done, so here
you've introduced something that is by-design going to fail periodically.
Not just if-and-when someone decides to move a computer and screws it up.
Of course, if someone actually removes the PC in question, and does not
realize that the network actually feeds _through_ the PC, um, well, you
cannot just whip a T out of your pocket to "fix" the network.

To me, this is a Dilbert-class engineering failure.  I would imagine that
if you could implement a hub on the network card, the same chip(s) would
work in an external tin can with a separate power supply.  Designing a 
product that actually exhibits a worse failure mode than 10base2 is ...
strange to me.

I was sarcastically referring to this as "backwards compatibility",
possibly also with New Enhanced Features, ha ha.

> Didn't the operational status of the LAX immigration 
> department fall to zero for almost a whole day, once; as a result of a 
> rogue network card crashing the LAN?

Probably.  Not my area of the country.  There are plenty of examples of
networking disasters.  ;-)

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

Re: what about 48 bits?

[Roland Perry]

In article <201004071023.o37antww018...@aurora.sol.net>, Joe Greco 
 writes



interoperability and backwards  compatibility were the tipping points.


Ah, yes, backwards compatibility: implementing the fantastic feature of
breaking the network...


By "backwards compatibility" I mean the ability to use the new LAN from 
a laptop that didn't have an Ethernet connection built in, and didn't 
have an optional [proprietary] internal Ethernet card available either.


Later on, of course, you would get PCMCIA cards and USB dongles rather 
than Centronics-port dongles. But the market for these remained 
dominated by the Ethernet standard, rather than others.



we all remember the fun of what happened when
someone incorrectly unhooked a 10base2 network segment; D-Link managed
to one-up that on the theoretically more-robust 10baseT/UTP by
introducing a card that'd break your network when you powered off the
attached PC.


That tale of woe doesn't really sound like it's the fault of backwards 
compatibility. Didn't the operational status of the LAX immigration 
department fall to zero for almost a whole day, once; as a result of a 
rogue network card crashing the LAN?

--
Roland Perry

Re: what about 48 bits?

[Joe Greco]

> For me, as an SME user, I started using Ethernet when Dlink introduced 
> an ISA card [DE205] which had a 4-port hub built in (actually 5-port if 
> you counted the internal one), at not a great deal more than a normal 
> 10Base-T card.  I think it was about $250, when a typical desktop PC was 
> $2500.
> 
> [...]
> 
> Price was a major feature, but interoperability and backwards 
> compatibility were the tipping points.

Ah, yes, backwards compatibility: implementing the fantastic feature of
breaking the network...  we all remember the fun of what happened when
someone incorrectly unhooked a 10base2 network segment; D-Link managed
to one-up that on the theoretically more-robust 10baseT/UTP by
introducing a card that'd break your network when you powered off the
attached PC.

Designer of that deserved to be whipped with some RG-58.  :-)

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

Re: what about 48 bits?

[Roland Perry]

In article <4bbbf070.6000...@sprunk.org>, Stephen Sprunk 
 writes

Ah, but what _caused_ Ethernet to become ubiquitous, given the price was
initially comparable?


For me, as an SME user, I started using Ethernet when Dlink introduced 
an ISA card [DE205] which had a 4-port hub built in (actually 5-port if 
you counted the internal one), at not a great deal more than a normal 
10Base-T card.  I think it was about $250, when a typical desktop PC was 
$2500.


So all I needed to build my network was one of those, some cable, and 
add-in Ethernet cards for each other PC I wanted to bring into the LAN. 
As icing on the cake, they also had a Centronics-port dongle to hook up 
almost all laptops very easily, and in an emergency you could even use 
it on a desktop.


Price was a major feature, but interoperability and backwards 
compatibility were the tipping points.

--
Roland Perry

Re: what about 48 bits?

[joel jaeggli]

On 4/6/2010 10:39 PM, Stephen Sprunk wrote:

On 05 Apr 2010 12:43, valdis.kletni...@vt.edu wrote:

On Mon, 05 Apr 2010 13:29:20 EDT, Jay Nakamura said:


I would have attributed the success of Ethernet to price!


You've got the causality wrong -- it wasn't cheap, way back when.


I remember back in '93~94ish (I think) you could get a off brand 10BT
card for less than $100, as oppose to Token Ring which was $300~400.
I can't remember anything else that was cheaper back then.  If you go
back before that, I don't know.


Steve is talking mid-80s pricing, not mid-90s.  By '93 or so, the fact
that Ethernet was becoming ubiquitous had already forced the price down.



Ah, but what _caused_ Ethernet to become ubiquitous, given the price was
initially comparable?


Early standardization.


The only explanation I can think of is the raft
of cheap NE2000 knock-offs that hit the market in the late 1980s, which
gave Ethernet a major price advantage over Token Ring (the chips for
which all vendors _had_ to buy from IBM at ridiculous cost).


Metcalf didn't make computers, whereas IBM and Datapoint did, protecting 
their captive markets cost both of them quite dearly.

Re: what about 48 bits?

[Stephen Sprunk]

On 05 Apr 2010 12:43, valdis.kletni...@vt.edu wrote:
> On Mon, 05 Apr 2010 13:29:20 EDT, Jay Nakamura said:
>   
 I would have attributed the success of Ethernet to price!
 
>>> You've got the causality wrong -- it wasn't cheap, way back when.
>>>   
>> I remember back in '93~94ish (I think) you could get a off brand 10BT
>> card for less than $100, as oppose to Token Ring which was $300~400.
>> I can't remember anything else that was cheaper back then.  If you go
>> back before that, I don't know.
>> 
> Steve is talking mid-80s pricing, not mid-90s.  By '93 or so, the fact
> that Ethernet was becoming ubiquitous had already forced the price down.
>   

Ah, but what _caused_ Ethernet to become ubiquitous, given the price was
initially comparable?  The only explanation I can think of is the raft
of cheap NE2000 knock-offs that hit the market in the late 1980s, which
gave Ethernet a major price advantage over Token Ring (the chips for
which all vendors _had_ to buy from IBM at ridiculous cost).  That, in
turn, led to mass adoption and further economies of scale, pushing the
price lower and lower in a virtuous cycle.  Still, lots of shops stuck
with TR well into the mid- and even late 1990s because Ethernet didn't
perform as well as TR under moderate to high utilization by multiple
hosts, not to mention IBM's insistence that TR was required for SNA.  It
wasn't until Ethernet switching came out, mostly solving CSMA/CD's
performance problems and eventually leading to full-duplex operation,
that it was entirely obvious which was going to win, and I spent several
years doing almost nothing but helping large enterprises convert to
Ethernet (usually with the help of DLSw).  By that point, off-brand
Ethernet chips cost _less than 1%_ of what IBM's TR chips did, thanks to
competition and sheer volume, so vendors had started including them "for
free" on every PC and server, and that was the final nail in TR's coffin.

(LocalTalk, ARCnet, and a variety of other physical layers suffered a
similar fate, but unlike IBM, their backers quickly switched to Ethernet
when they realized they couldn't compete with it on price _or_ on
performance given their limited volumes, so those deaths were more
sudden and absolute than TR's.)

As to why no other technology has managed to dislodge Ethernet, though,
I think it's fairly clear that's because the various successors to
10BaseT have all maintained the same connector and the same framing,
which makes for trivial upgrades that deliver regular (and significant)
performance improvements as customers' equipment replacement cycle turns.

S

-- 
Stephen Sprunk "God does not play dice."  --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSSdice at every possible opportunity." --Stephen Hawking




smime.p7s
Description: S/MIME Cryptographic Signature

Re: what about 48 bits?

[Robert Bonomi]

> From: Steven Bellovin 
> Date: Mon, 5 Apr 2010 13:51:23 -0400
> Cc: NANOG 
>
> On Apr 5, 2010, at 1:43 52PM, valdis.kletni...@vt.edu wrote:
>
> > On Mon, 05 Apr 2010 13:29:20 EDT, Jay Nakamura said:
>  I would have attributed the success of Ethernet to price!
> =20
> =20
> >>> You've got the causality wrong -- it wasn't cheap, way back when.
> >>=20
> >> I remember back in '93~94ish (I think) you could get a off brand 10BT
> >> card for less than $100, as oppose to Token Ring which was $300~400.
> >> I can't remember anything else that was cheaper back then.  If you go
> >> back before that, I don't know.
> >=20
> > Steve is talking mid-80s pricing, not mid-90s.  By '93 or so, the fact
> > that Ethernet was becoming ubiquitous had already forced the price =
> down.
>
> Yup.  10 years earlier, a 3Com Ethernet card for a Vax cost about $1500, =
> if memory serves.

That ball-park anyway -- ethernet for VMEbus or VERSAbus was in the same price
range.

Just a _few_ years later, ARCnet was one of several signficantly less expensive
alternatives for limited-size (both in number of hosts, and distance) LANS.

Re: what about 48 bits?

[Jon Lewis]

On Mon, 5 Apr 2010, Patrick W. Gilmore wrote:


Until you buy 25 cards with the same MAC address and deploy them all across
your enterprise


I don't think that's possible given that Jon was suggesting.


Given what I was suggesting, no...but there have been multiple cases of a 
vendor screwing up and producing large runs of devices/cards all with the 
same MAC address.  IIRC, there was a batch of Netgear PCI NICs where you 
might find all the NICs in a multipack box had the same MAC address.


--
 Jon Lewis   |  I route
 Senior Network Engineer |  therefore you are
 Atlantic Net|
_ http://www.lewis.org/~jlewis/pgp for PGP public key_

Re: what about 48 bits?

[joel jaeggli]

On 4/5/2010 5:26 PM, Patrick W. Gilmore wrote:

On Apr 5, 2010, at 5:08 PM, valdis.kletni...@vt.edu wrote:

On Mon, 05 Apr 2010 16:36:26 EDT, Jon Lewis said:


Since they only really need to be unique per broadcast domain, it
doesn't really matter.  You can I could use the same MAC
addresses on all our home gear, and never know it.  For
manufacturers, it's probably reasonably safe to reuse MAC
addresses they put on 10mbit ISA ethernet cards...if they were a
manufacturer back then.


Until you buy 25 cards with the same MAC address and deploy them
all across your enterprise


I don't think that's possible given that Jon was suggesting.

I'm 3COM, I made ISA 10Base2 / 10Base5 cards in the 90s.  I run out
of MAC addresses.  Instead of going to get more - if I even can! - I
recycle those MAC addresses, figuring the 10GE PCI-X cards I'm making
now have 0.000% chance of being on the same b-cast domain as one of
those old ISA cards.

Even if I am wrong, the max collision possibility is 2, not 25.

Seems reasonable.  If I am wrong, I'll apologize profusely, refund
the price of the 10G card I gave the customer, ship him a new one
free, so he gets two he can use (assuming he has more than one b-cast
domain), which would probably make the customer happy.  Wanna bet how
many times 3COM would have to ship free 10GE cards?


3com is now HP and i doubt very much that either company would bother 
with that approach...


That said, the volume production run for a circa 1992 isa bus ethernet 
nic (or the enitre sun microsystems product line for that matter) is 
propably two orders of magnitude lower than say the minimum volume 
production of mini-pci-express wireless card that goes into a laptop, 
and laptops might have two or three mac addresses.

Re: what about 48 bits?

[Larry Sheldon]

On 4/5/2010 15:36, Jon Lewis wrote:
> On Sun, 4 Apr 2010, A.B. Jr. wrote:
> 
>> Hi,
>>
>> Lots of traffic recently about 64 bits being too short or too long.
>>
>> What about mac addresses? Aren't they close to exhaustion? Should be. Or it
>> is assumed that mac addresses are being widely reused throughout the world?
>> All those low cost switches and wifi adapters DO use unique mac addresses?
> 
> Since they only really need to be unique per broadcast domain, it doesn't 
> really matter.  You can I could use the same MAC addresses on all our home 
> gear, and never know it.  For manufacturers, it's probably reasonably safe 
> to reuse MAC addresses they put on 10mbit ISA ethernet cards...if they 
> were a manufacturer back then.

Seems like they have be unique within a DHCP "domain".  And you'd have
to pretty much outlaw mobiles.

Wouldn't you?  (Is there an accepted bit of nomenclature for all of the
networks that forward DHCP traffic to a given cluster of servers?)
-- 
Democracy: Three wolves and a sheep voting on the dinner menu.

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Re: what about 48 bits?

[Franck Martin]

- "Valdis Kletnieks"  wrote:

> On Mon, 05 Apr 2010 17:26:53 EDT, "Patrick W. Gilmore" said:
> > I'm 3COM, I made ISA 10Base2 / 10Base5 cards in the 90s.  I run out
> of
> > MAC addresses.  Instead of going to get more - if I even can! - I
> > recycle those MAC addresses
> 
> There were several cases of production run errors from multiple
> vendors,
> where the MAC address went 14, 15, 16, 17, 17, 17, 17, *thwack*, 18,
> 19

And to make the problem worse, they are likely to end up in the same shop, and 
you get them when you purchase several of them.

Re: what about 48 bits?

[Valdis . Kletnieks]

On Mon, 05 Apr 2010 17:26:53 EDT, "Patrick W. Gilmore" said:
> I'm 3COM, I made ISA 10Base2 / 10Base5 cards in the 90s.  I run out of
> MAC addresses.  Instead of going to get more - if I even can! - I
> recycle those MAC addresses

There were several cases of production run errors from multiple vendors,
where the MAC address went 14, 15, 16, 17, 17, 17, 17, *thwack*, 18, 19


pgpCbbW5s5guV.pgp
Description: PGP signature

Re: what about 48 bits?

[Patrick W. Gilmore]

On Apr 5, 2010, at 5:08 PM, valdis.kletni...@vt.edu wrote:
> On Mon, 05 Apr 2010 16:36:26 EDT, Jon Lewis said:
> 
>> Since they only really need to be unique per broadcast domain, it doesn't 
>> really matter.  You can I could use the same MAC addresses on all our home 
>> gear, and never know it.  For manufacturers, it's probably reasonably safe 
>> to reuse MAC addresses they put on 10mbit ISA ethernet cards...if they 
>> were a manufacturer back then.
> 
> Until you buy 25 cards with the same MAC address and deploy them all across
> your enterprise

I don't think that's possible given that Jon was suggesting.

I'm 3COM, I made ISA 10Base2 / 10Base5 cards in the 90s.  I run out of MAC 
addresses.  Instead of going to get more - if I even can! - I recycle those MAC 
addresses, figuring the 10GE PCI-X cards I'm making now have 0.000% chance of 
being on the same b-cast domain as one of those old ISA cards.

Even if I am wrong, the max collision possibility is 2, not 25.

Seems reasonable.  If I am wrong, I'll apologize profusely, refund the price of 
the 10G card I gave the customer, ship him a new one free, so he gets two he 
can use (assuming he has more than one b-cast domain), which would probably 
make the customer happy.  Wanna bet how many times 3COM would have to ship free 
10GE cards?

-- 
TTFN,
patrick


> - the problem can go un-noticed for *weeks* as long as two
> boxes aren't squawking on the same subnet at the same time(*).  Of course, you
> never stop to actually *check* that two cards in different machines have the
> same address, because That Never Happens, and you spin your wheels trying to
> figure out why your switching gear is confused about the MAC addresses it's
> seeing (and it always takes 3 or 4 tickets before one actually includes the
> message "Duplicate MAC address detected" in the problem report..)
> 
> (*) And as Murphy predicts, whenever it happens, one of the two offenders will
> give up in disgust, power off the machine, and go on coffee break so the arp
> cache has timed out by the time you start trying to work the trouble ticket. 
> ;)
> 
> (Yes, we're mostly older and wiser now, and more willing to include "the 
> damned
> hardware is posessed by an Imp of Perversity" in our troubleshooting analysis.
> Had an SL8500 tape library last week that reported 'Drive State: Unpowered' 
> and
> 'Drive Status: Not Communicating' and still reported 'Drive Health: Good'.
> 

Re: what about 48 bits?

[Bill Stewart]

On Mon, Apr 5, 2010 at 10:51 AM, Steven Bellovin  wrote:
> On Apr 5, 2010, at 1:43 52PM, valdis.kletni...@vt.edu wrote:
>> Steve is talking mid-80s pricing, not mid-90s.  By '93 or so, the fact
>> that Ethernet was becoming ubiquitous had already forced the price down.
>
> Yup.  10 years earlier, a 3Com Ethernet card for a Vax cost about $1500, if 
> memory serves.

$1500 is what I remember also (forget if that was the Interlan NI1010
or the DEUNA / DELUA),
plus of course the cost of whatever Unibus you're burning the bandwidth on.
Serial was cheaper, but most of the competition wasn't.
I assume Datakit boards had a regular list price for customers other
than intra-Bell?

-- 

 Thanks; Bill

Note that this isn't my regular email account - It's still experimental so far.
And Google probably logs and indexes everything you send it.

Re: what about 48 bits?

[Valdis . Kletnieks]

On Mon, 05 Apr 2010 16:36:26 EDT, Jon Lewis said:

> Since they only really need to be unique per broadcast domain, it doesn't 
> really matter.  You can I could use the same MAC addresses on all our home 
> gear, and never know it.  For manufacturers, it's probably reasonably safe 
> to reuse MAC addresses they put on 10mbit ISA ethernet cards...if they 
> were a manufacturer back then.

Until you buy 25 cards with the same MAC address and deploy them all across
your enterprise - the problem can go un-noticed for *weeks* as long as two
boxes aren't squawking on the same subnet at the same time(*).  Of course, you
never stop to actually *check* that two cards in different machines have the
same address, because That Never Happens, and you spin your wheels trying to
figure out why your switching gear is confused about the MAC addresses it's
seeing (and it always takes 3 or 4 tickets before one actually includes the
message "Duplicate MAC address detected" in the problem report..)

(*) And as Murphy predicts, whenever it happens, one of the two offenders will
give up in disgust, power off the machine, and go on coffee break so the arp
cache has timed out by the time you start trying to work the trouble ticket. ;)

(Yes, we're mostly older and wiser now, and more willing to include "the damned
hardware is posessed by an Imp of Perversity" in our troubleshooting analysis.
Had an SL8500 tape library last week that reported 'Drive State: Unpowered' and
'Drive Status: Not Communicating' and still reported 'Drive Health: Good'.



pgpXz7joTNrD8.pgp
Description: PGP signature

Re: what about 48 bits?

[Steven Bellovin]

On Apr 5, 2010, at 4:58 59PM, Barry Shein wrote:

> 
> On April 5, 2010 at 13:51 s...@cs.columbia.edu (Steven Bellovin) wrote:
>> 
>> Yup.  10 years earlier, a 3Com Ethernet card for a Vax cost about $1500, if 
>> memory serves.
> 
> Early-mid 80s? I'd say at least twice that, I don't think there were
> too many cards for Vaxes and similar for less than $5K.

It could have been $3K, but I don't think it was higher.
> 
> An NIU20 for DECSYSTEM-20 was a 3U box, it was just a single ethernet
> interface, and cost around $15-20K.
> 
> About the same price for an IBM370 (specifically, 3090) ethernet box
> which included a PC/AT and sat on a box about the size of a dorm cube
> refrigerator which, if you opened it up, contained a chunk of Unibus
> backplane in which was a (I think 3COM?) ethernet board (and power
> supply etc.), some common Vax ethernet card. Weird, the whole thing
> was basically a kludged together Unibus to bus/tag channel adapter or
> maybe even 3274 using something like an IRMA board? I knew it well
> because it crashed a lot and operations decided I was the only one who
> had the magic voodoo to bring it back to life which as I remember was
> to POWER-CYCLE IT! Well, sometimes you had to power-cycle it more than
> once to get it all to synch.

I remember the design, but never used it.
> 
> And we had to put coins in those boxes to get our packets through! If
> you wanted an email it cost a dime, FTP was 75cents for the first
> 100KB and 10c for each KB thereafter...ok, that may not be entirely
> accurate.
> 

Of course not -- you forgot about the credit card reader option.


--Steve Bellovin, http://www.cs.columbia.edu/~smb

Re: what about 48 bits?

[Barry Shein]

On April 5, 2010 at 13:51 s...@cs.columbia.edu (Steven Bellovin) wrote:
 > 
 > Yup.  10 years earlier, a 3Com Ethernet card for a Vax cost about $1500, if 
 > memory serves.

Early-mid 80s? I'd say at least twice that, I don't think there were
too many cards for Vaxes and similar for less than $5K.

An NIU20 for DECSYSTEM-20 was a 3U box, it was just a single ethernet
interface, and cost around $15-20K.

About the same price for an IBM370 (specifically, 3090) ethernet box
which included a PC/AT and sat on a box about the size of a dorm cube
refrigerator which, if you opened it up, contained a chunk of Unibus
backplane in which was a (I think 3COM?) ethernet board (and power
supply etc.), some common Vax ethernet card. Weird, the whole thing
was basically a kludged together Unibus to bus/tag channel adapter or
maybe even 3274 using something like an IRMA board? I knew it well
because it crashed a lot and operations decided I was the only one who
had the magic voodoo to bring it back to life which as I remember was
to POWER-CYCLE IT! Well, sometimes you had to power-cycle it more than
once to get it all to synch.

And we had to put coins in those boxes to get our packets through! If
you wanted an email it cost a dime, FTP was 75cents for the first
100KB and 10c for each KB thereafter...ok, that may not be entirely
accurate.

   -b

Re: what about 48 bits?

[Jon Lewis]

On Sun, 4 Apr 2010, A.B. Jr. wrote:


Hi,

Lots of traffic recently about 64 bits being too short or too long.

What about mac addresses? Aren't they close to exhaustion? Should be. Or it
is assumed that mac addresses are being widely reused throughout the world?
All those low cost switches and wifi adapters DO use unique mac addresses?


Since they only really need to be unique per broadcast domain, it doesn't 
really matter.  You can I could use the same MAC addresses on all our home 
gear, and never know it.  For manufacturers, it's probably reasonably safe 
to reuse MAC addresses they put on 10mbit ISA ethernet cards...if they 
were a manufacturer back then.


--
 Jon Lewis   |  I route
 Senior Network Engineer |  therefore you are
 Atlantic Net|
_ http://www.lewis.org/~jlewis/pgp for PGP public key_

Re: what about 48 bits?

[Nick Hilliard]

On 05/04/2010 18:51, Steven Bellovin wrote:

Yup.  10 years earlier, a 3Com Ethernet card for a Vax cost about $1500, if 
memory serves.


To be fair, everything for a vax was somewhat pricey.  And slow.

On an even more unrelated note, does anyone remember the day that 
CMU-TEK tcp/ip stopped working some time in the early 1990s?  That was a 
load of fun.


Nick

Re: what about 48 bits?

[Steven Bellovin]

On Apr 5, 2010, at 1:43 52PM, valdis.kletni...@vt.edu wrote:

> On Mon, 05 Apr 2010 13:29:20 EDT, Jay Nakamura said:
 I would have attributed the success of Ethernet to price!
 
 
>>> You've got the causality wrong -- it wasn't cheap, way back when.
>> 
>> I remember back in '93~94ish (I think) you could get a off brand 10BT
>> card for less than $100, as oppose to Token Ring which was $300~400.
>> I can't remember anything else that was cheaper back then.  If you go
>> back before that, I don't know.
> 
> Steve is talking mid-80s pricing, not mid-90s.  By '93 or so, the fact
> that Ethernet was becoming ubiquitous had already forced the price down.

Yup.  10 years earlier, a 3Com Ethernet card for a Vax cost about $1500, if 
memory serves.

--Steve Bellovin, http://www.cs.columbia.edu/~smb

Re: what about 48 bits?

[Valdis . Kletnieks]

On Mon, 05 Apr 2010 13:29:20 EDT, Jay Nakamura said:
> >> I would have attributed the success of Ethernet to price!
> >>
> >>
> > You've got the causality wrong -- it wasn't cheap, way back when.
> 
> I remember back in '93~94ish (I think) you could get a off brand 10BT
> card for less than $100, as oppose to Token Ring which was $300~400.
> I can't remember anything else that was cheaper back then.  If you go
> back before that, I don't know.

Steve is talking mid-80s pricing, not mid-90s.  By '93 or so, the fact
that Ethernet was becoming ubiquitous had already forced the price down.


pgp4RHlf8PxU7.pgp
Description: PGP signature

Re: what about 48 bits?

[Jay Nakamura]

>> I would have attributed the success of Ethernet to price!
>>
>>
> You've got the causality wrong -- it wasn't cheap, way back when.

I remember back in '93~94ish (I think) you could get a off brand 10BT
card for less than $100, as oppose to Token Ring which was $300~400.
I can't remember anything else that was cheaper back then.  If you go
back before that, I don't know.

-Jay

Re: what about 48 bits?

[Steven Bellovin]

On Apr 5, 2010, at 12:09 02PM, Jay Nakamura wrote:

>> negotiation and backward compatibility.  I think that one of the
>> reasons for the continuing success of "Ethernet" technologies has been
>> implementation simplicity and 100% compatibility above the level of
>> the NIC.
> 
> I would have attributed the success of Ethernet to price!
> 
> 
You've got the causality wrong -- it wasn't cheap, way back when.  

--Steve Bellovin, http://www.cs.columbia.edu/~smb

Re: what about 48 bits?

[Jay Nakamura]

> negotiation and backward compatibility.  I think that one of the
> reasons for the continuing success of "Ethernet" technologies has been
> implementation simplicity and 100% compatibility above the level of
> the NIC.

I would have attributed the success of Ethernet to price!

Re: what about 48 bits?

[Bill Bogstad]

On Mon, Apr 5, 2010 at 12:05 AM, joel jaeggli  wrote:
> On 4/4/2010 7:57 PM, Richard A Steenbergen wrote:
>>
>> On Mon, Apr 05, 2010 at 10:57:46AM +0930, Mark Smith wrote:
>>>
>>> Has anybody considered lobbying the IEEE to do a point to point version
>>> of Ethernet to gets rid of addressing fields? Assuming an average 1024
>>> byte packet size, on a 10Gbps link they're wasting 100+ Mbps. 100GE /
>>> 1TE starts to make it even more worth doing.
>>
>> If you're lobbying to have the IEEE do something intelligent to Ethernet
>> why don't you start with a freaking standardization of jumbo frames. The
>> lack of a real standard and any type of negotiation protocol for two
>> devices under different administrative control are all but guaranteeing
>> end to end jumbo frame support will never be practical.
>
> Not that I disagree, given that we use them rather a lot but 7.2usec (at
> 10Gbe) is sort of a long time to wait before a store and forward arch switch
> gets down to the task of figuring out what to do with the packet. The
> problem gets worse if mtu sizes bigger than 9k ever become popular,  kind of
> like being stuck behind an elephant while boarding an elevator.

I didn't run the numbers,  but my guesstimate is that would be roughly
half the latency that a max sized standard packet would have taken on
a 1Gbe switch.   It sound reasonable to me that at some point during
the march from 10->100->1000->1 mbit/sec a decision could have
been made that one of those upgrades would only decrease max. per hop
packet latency by a factor of 2 rather then 10.  Particularly since
when first introduced, each speed increment was typically used for
aggregating a bunch of slower speed links which meant that the actual
minimum total latency was already being  constrained by the latency on
those slower links anyway.

OTOH, I totally buy the argument on the difficulty of frame size
negotiation and backward compatibility.  I think that one of the
reasons for the continuing success of "Ethernet" technologies has been
implementation simplicity and 100% compatibility above the level of
the NIC.

Bill Bogstad

Re: what about 48 bits?

[Kevin Oberman]

> Date: Sun, 04 Apr 2010 23:30:42 -0500
> From: Larry Sheldon 
> 
> I keep seeing mention here of the "permanent" MAC address.
> 
> Really?  Permanent?
> 
> Been a long time, but it seems like one of the fun things about having
> DECNet-phase IV on the network was its propensity for changing the MAC
> address to be the DECNet address.
> 
> And it seems like the HP-UX machines (among others) could write what
> every they wanted to as addresses.

Almost every system can re-write the MAC address. It's in the original
802.3 and DIX (Blue Book) Ethernet standards. I have not run into a
system in some time that lacked this capability. Works on Windows,
MacOS, Linux, and BSD.

That said, all 802.3 devices are expected to have a permanent MAC
address in ROM. At initialization time, that address is always used
until software can program in the new address. Made MOP-DL booting
(DECnet equivalent of bootp) interesting.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: ober...@es.net  Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751

Re: what about 48 bits?

[Larry Sheldon]

I keep seeing mention here of the "permanent" MAC address.

Really?  Permanent?

Been a long time, but it seems like one of the fun things about having
DECNet-phase IV on the network was its propensity for changing the MAC
address to be the DECNet address.

And it seems like the HP-UX machines (among others) could write what
every they wanted to as addresses.
-- 
Democracy: Three wolves and a sheep voting on the dinner menu.

Requiescas in pace o email
Ex turpi causa non oritur actio
Eppure si rinfresca

ICBM Targeting Information:  http://tinyurl.com/4sqczs
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Re: what about 48 bits?

[Scott Howard]

On Sun, Apr 4, 2010 at 9:17 PM, A.B. Jr.  wrote:

> While most of end user devices work with temporarily assigned IP addresses,
> or even with RFC1918 behind a NAT, very humble ethernet devices come from
> factory with a PERMANENTE unique mac address.


Just don't tell Greenpeace - I don't think we're quite at the state yet
where we need to start recycling the MAC addresses from thrown out CPE
routers.  Plus I'm sure the CA government will be more than happy to add a
$4/device recycling fee for anything sold with a MAC address if they find
out about it.

  Scott

(PS, I've run out of Popcorn - anyone got to share?)

Re: what about 48 bits?

[A.B. Jr.]

2010/4/4 Scott Howard 

> On Sun, Apr 4, 2010 at 1:51 PM, Matthew Kaufman 
> wrote:
>
> > http://en.wikipedia.org/wiki/MAC_address
> >>
> >> The IEEE expects the MAC-48 space to be exhausted no sooner than the
> year
> >> 2100[3]; EUI-64s are not expected to run out in the foreseeable future.
> >>
> >>
> >
> > And this is what happens when you can use 100% of the bits on "endpoint
> > identity" and not waste huge sections of them on the decision bits for
> > "routing topology".
> >
>
> Having around 4 orders of magnitude more addresses probably doesn't hurt
> either...
>
> Although even MAC-48 addresses are "wasteful" in that only 1/4 of them are
> assignable to/by vendors, with the other 3/4 being assigned to multicast
> and
> local addresses (the MAC equivalent of RFC1918)
>
>  Scott.
>



Wasteful in many ways.



While most of end user devices work with temporarily assigned IP addresses,
or even with RFC1918 behind a NAT, very humble ethernet devices come from
factory with a PERMANENTE unique mac address.



And one of those devices are thrown away – let’s say a cell  phone with
wifi, or a cheap NIC PC card - the mac address is lost forever. Doesn’t this
sound not reasonable?

A.b. --

Re: what about 48 bits?

[joel jaeggli]

On 4/4/2010 7:57 PM, Richard A Steenbergen wrote:

On Mon, Apr 05, 2010 at 10:57:46AM +0930, Mark Smith wrote:


Has anybody considered lobbying the IEEE to do a point to point version
of Ethernet to gets rid of addressing fields? Assuming an average 1024
byte packet size, on a 10Gbps link they're wasting 100+ Mbps. 100GE /
1TE starts to make it even more worth doing.


If you're lobbying to have the IEEE do something intelligent to Ethernet
why don't you start with a freaking standardization of jumbo frames. The
lack of a real standard and any type of negotiation protocol for two
devices under different administrative control are all but guaranteeing
end to end jumbo frame support will never be practical.


Not that I disagree, given that we use them rather a lot but 7.2usec (at 
10Gbe) is sort of a long time to wait before a store and forward arch 
switch gets down to the task of figuring out what to do with the packet. 
The problem gets worse if mtu sizes bigger than 9k ever become popular, 
 kind of like being stuck behind an elephant while boarding an elevator.

Re: what about 48 bits?

[Jorge Amodio]

> And then there was the time an electrician accidentally cut the coax and 
> decided to splice it with black electrical tape...

He, he, we had all sorts of issues, ethernet was not a very well known
technology yet. We had a radio antenna on the roof and when the guys
doing the install saw a coax they assumed it was their 75 ohm drop to
the radio equipment, never took the time to look at the labels on the
cable, what a mess.

At the Argentinean Embassy in WDC they had a pet dog that had the bad
habit to chew on the thin ethernet cables, we didn't have any TDR
tools so we had to befriend the damn dog to be able to follow him to
find where the heck the cable was exposed and chewed.

No doubt technology has evolved, for some people sshing from an iPod
touch may feel like "yaaa another app" for me it feels amazing !!

Cheers
Jorge

Re: what about 48 bits?

[Steven Bellovin]

On Apr 4, 2010, at 11:29 47PM, Jorge Amodio wrote:

>> The N connectors were easier to deal with than the vampire taps.  To add
>> a node, you just "spliced" a new xceiver box onto the line where you
>> needed it by screwing a new length of cable into the new + existng
>> xceivers, then connecting the AUI drop cable from the box to the node.
> 
> I've to say it, the AUI cables were an absolute pain in the ass to deal with.
> 
> We had also a thick coax with the vampire taps and AUI fan outs from
> Excellan. Dealing with the coax was not that bad since we made an
> inverted U and had a coax run on each of the two vertical raisers this
> particular building had.
> 
> The biggest challenge was to go from the raiser using the existing
> horizontal conduits that were not that big, and run the AUI from the
> XCVR to the fanout unit and then from that unit to each desk.
> 
> Before going to 10BaseT we used pre-standard LattisNet from SynOptics,
> getting rid of the AUI was a relief.
> 
Oh, the thick coax and the AUIs were lots of fun.  The 15-ping cables from the 
hosts to the AUIs were always coming loose, and the slide locks didn't help 
much.  The vampire taps tended to either not make good enough contact or to 
break the center conductor.  The N-connectors were easier to handle -- but 
cutting the cable and crimping on a pair took down the whole network.  

And then there was the time an electrician accidentally cut the coax and 
decided to splice it with black electrical tape...


--Steve Bellovin, http://www.cs.columbia.edu/~smb

Re: what about 48 bits?

[Jorge Amodio]

> The N connectors were easier to deal with than the vampire taps.  To add
> a node, you just "spliced" a new xceiver box onto the line where you
> needed it by screwing a new length of cable into the new + existng
> xceivers, then connecting the AUI drop cable from the box to the node.

I've to say it, the AUI cables were an absolute pain in the ass to deal with.

We had also a thick coax with the vampire taps and AUI fan outs from
Excellan. Dealing with the coax was not that bad since we made an
inverted U and had a coax run on each of the two vertical raisers this
particular building had.

The biggest challenge was to go from the raiser using the existing
horizontal conduits that were not that big, and run the AUI from the
XCVR to the fanout unit and then from that unit to each desk.

Before going to 10BaseT we used pre-standard LattisNet from SynOptics,
getting rid of the AUI was a relief.

Cheers
Jorge

Re: what about 48 bits?

[Jim Burwell]

On 4/4/2010 19:16, Mark Smith wrote:
<-snip->
> Actually the IEEE have never called it "Ethernet", it's all been IEEE
> 802.3 / XXX{BASE|BROAD}-BLAH.
>
> "Ethernet", assuming version 1 and 2, strictly means thick coax, vampire
> taps and AUI connectors running at (half-duplex) 10Mbps. I saw some of
> it once.
>   
I worked with it at my first job at a large government institution. 
Talk about painful and unweildy.  We had parts of our network wired with
10base5 (thick ethernet) with vampire taps, and had some segments wired
with transceivers which had a pair of threaded "type N connectors" (not
sure if this is the proper name ... it's what my boss called them ...
looked like oversized CATV F connectors).   The xceiver boxes were
pretty big (4-5 inches wide) and connected to the node via an AUI  drop
cable.

The N connectors were easier to deal with than the vampire taps.  To add
a node, you just "spliced" a new xceiver box onto the line where you
needed it by screwing a new length of cable into the new + existng
xceivers, then connecting the AUI drop cable from the box to the node.

Eventually we went to 10base2 (thin ethernet) and then like everyone
else, 10baseT hubs. 

Re: what about 48 bits?

[Richard A Steenbergen]

On Mon, Apr 05, 2010 at 10:57:46AM +0930, Mark Smith wrote:
> 
> Has anybody considered lobbying the IEEE to do a point to point version
> of Ethernet to gets rid of addressing fields? Assuming an average 1024
> byte packet size, on a 10Gbps link they're wasting 100+ Mbps. 100GE /
> 1TE starts to make it even more worth doing.

If you're lobbying to have the IEEE do something intelligent to Ethernet
why don't you start with a freaking standardization of jumbo frames. The
lack of a real standard and any type of negotiation protocol for two
devices under different administrative control are all but guaranteeing
end to end jumbo frame support will never be practical.

-- 
Richard A Steenbergenhttp://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)

Re: what about 48 bits?

[Mark Smith]

On Mon, 5 Apr 2010 01:57:41 GMT
msoko...@ivan.harhan.org (Michael Sokolov) wrote:

> Mark Smith  wrote:
> 
> > Has anybody considered lobbying the IEEE to do a point to point version
> > of Ethernet to gets rid of addressing fields? [...]
> > Actually the minimum 64 byte packet size could probably go too, as that
> > was only there for collision detection.
> 
> And maybe rename it to something else while you are at it?  All those
> people who have hijacked the name "Ethernet" for PtP links (all those
> "Ethernet" UTP media are really PtP at the physical level, unlike real
> coaxial Ethernet) are despicable thieves - now those of us who are still
> using the original coaxial Ethernet in the shared bus mode are left
> without a clear, unique and distinctive name we once had to refer to
> what we use.
> 

Actually the IEEE have never called it "Ethernet", it's all been IEEE
802.3 / XXX{BASE|BROAD}-BLAH.

"Ethernet", assuming version 1 and 2, strictly means thick coax, vampire
taps and AUI connectors running at (half-duplex) 10Mbps. I saw some of
it once.

Regards,
Mark.

Re: what about 48 bits?

[Michael Sokolov]

Mark Smith  wrote:

> Has anybody considered lobbying the IEEE to do a point to point version
> of Ethernet to gets rid of addressing fields? [...]
> Actually the minimum 64 byte packet size could probably go too, as that
> was only there for collision detection.

And maybe rename it to something else while you are at it?  All those
people who have hijacked the name "Ethernet" for PtP links (all those
"Ethernet" UTP media are really PtP at the physical level, unlike real
coaxial Ethernet) are despicable thieves - now those of us who are still
using the original coaxial Ethernet in the shared bus mode are left
without a clear, unique and distinctive name we once had to refer to
what we use.

MS

Re: what about 48 bits?

[Mark Smith]

On Sun, 4 Apr 2010 14:05:50 -0700
Scott Howard  wrote:

> On Sun, Apr 4, 2010 at 1:51 PM, Matthew Kaufman  wrote:
> 
> > http://en.wikipedia.org/wiki/MAC_address
> >>
> >> The IEEE expects the MAC-48 space to be exhausted no sooner than the year
> >> 2100[3]; EUI-64s are not expected to run out in the foreseeable future.
> >>
> >>
> >
> > And this is what happens when you can use 100% of the bits on "endpoint
> > identity" and not waste huge sections of them on the decision bits for
> > "routing topology".
> >
> 
> Having around 4 orders of magnitude more addresses probably doesn't hurt
> either...
> 
> Although even MAC-48 addresses are "wasteful" in that only 1/4 of them are
> assignable to/by vendors, with the other 3/4 being assigned to multicast and
> local addresses (the MAC equivalent of RFC1918)
> 

Has anybody considered lobbying the IEEE to do a point to point version
of Ethernet to gets rid of addressing fields? Assuming an average 1024
byte packet size, on a 10Gbps link they're wasting 100+ Mbps. 100GE /
1TE starts to make it even more worth doing.

Actually the minimum 64 byte packet size could probably go too, as that
was only there for collision detection.

>   Scott.

Re: what about 48 bits?

[Mark Smith]

On Sun, 04 Apr 2010 11:17:28 -0400
John Peach  wrote:

> On Sun, 4 Apr 2010 11:10:56 -0400
> David Andersen  wrote:
> 
> > There are some classical cases of assigning the same MAC address to every 
> > machine in a batch, resetting the counter used to number them, etc.;  
> > unless shown otherwise, these are likely to be errors, not accidental 
> > collisions.
> > 
> >   -Dave
> > 
> > On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
> > 
> > > I've seen duplicate addresses in the wild in the past, I assume there
> > > is some amount of reuse, even though they are suppose to be unique.
> > > 
> > > -jim
> > > 
> > > On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
> > >> Hi,
> > >> 
> > >> Lots of traffic recently about 64 bits being too short or too long.
> > >> 
> > >> What about mac addresses? Aren't they close to exhaustion? Should be. Or 
> > >> it
> > >> is assumed that mac addresses are being widely reused throughout the 
> > >> world?
> > >> All those low cost switches and wifi adapters DO use unique mac 
> > >> addresses?
> > >> 
> Sun, for one, used to assign the same MAC address to every NIC in the
> same box.
> 

That actually follows the original MAC addressing model -

"48-bit Absolute Internet and Ethernet Host Numbers"
http://ethernethistory.typepad.com/papers/HostNumbers.pdf

As add-in cards needed their own address, because they couldn't be sure
the host had one, and most likely didn't, I think that has evolved into
unique MAC addresses per-interface rather than per-host.

Regards,
Mark.

Re: what about 48 bits?

[James Hess]

On Sun, Apr 4, 2010 at 9:53 AM, A.B. Jr.  wrote:
> Lots of traffic recently about 64 bits being too short or too long.
> What about mac addresses? Aren't they close to exhaustion? Should be. Or it
> is assumed that mac addresses are being widely reused throughout the world?
> All those low cost switches and wifi adapters DO use unique mac addresses?

Hardware MAC-48 addresses are not assigned based on a network
topology.  The first 24 bits are used for  OUI   which is an ID number
applied for [and paid for] by a manufacturer of network devices,   the
2nd LSB of the most significant byte is reserved for  'local vs
universal  administration flag',  and the LSB of the most significant
byte is reserved for unicast/multicast flag.  The bottom 24 bits
are assigned by manufacturer.

So there are  22 bits of usable global unicast OUIs,  that is
4,194,304 possible.
and each OUI has   16,777,216   MAC address numbers.

Of the possible OUIs,  only 13,557   are currently listed as allocated
 in  the IEEE   OUI  listing.
http://standards.ieee.org/regauth/oui/index.shtml

So a theoretical maximum of   227,448,717,312 unicast  MAC addresses
could be globally assigned today (which is a vast overestimate,
assuming all presently assigned OUIs  are already completely
exhausted).   Out of  70,368,744,177,664,   that is   what, 0.3%  ?


--
-J

Re: what about 48 bits?

[John Peach]

On Sun, 04 Apr 2010 14:48:38 -0700
Jim Burwell  wrote:

> On 4/4/2010 08:46, Jonathan Lassoff wrote:
> > Excerpts from John Peach's message of Sun Apr 04 08:17:28 -0700 2010:
> >   
> >> On Sun, 4 Apr 2010 11:10:56 -0400
> >> David Andersen  wrote:
> >>
> >> 
> >>> There are some classical cases of assigning the same MAC address to every 
> >>> machine in a batch, resetting the counter used to number them, etc.;  
> >>> unless shown otherwise, these are likely to be errors, not accidental 
> >>> collisions.
> >>>
> >>>   -Dave
> >>>
> >>> On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
> >>>
> >>>   
>  I've seen duplicate addresses in the wild in the past, I assume there
>  is some amount of reuse, even though they are suppose to be unique.
> 
>  -jim
> 
>  On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
>  
> > Hi,
> >
> > Lots of traffic recently about 64 bits being too short or too long.
> >
> > What about mac addresses? Aren't they close to exhaustion? Should be. 
> > Or it
> > is assumed that mac addresses are being widely reused throughout the 
> > world?
> > All those low cost switches and wifi adapters DO use unique mac 
> > addresses?
> >
> >   
> >> Sun, for one, used to assign the same MAC address to every NIC in the
> >> same box.
> >> 
> > I could see how that *could* work as long as each interface connected to
> > a different LAN.
> >   
> That was a logic Sun used.  Every NIC would be connected to a different
> subnet, so duplicate MACs shouldn't be a problem.  For the most part
> this worked, but some situations required a unique MAC per NIC, and Sun
> had a bit you could flip to turn this on.  I believe it was an OpenBoot
> prom variable called "local-mac-address?" which you'd set to true if you
> wanted it to use each NICs MAC instead of the "system MAC".

You can set the MAC address to whatever you want in Solaris, using
ifconfig and local-mac-address was (is) the PROM variable.


-- 
John

Re: what about 48 bits?

[Jim Burwell]

On 4/4/2010 08:46, Jonathan Lassoff wrote:
> Excerpts from John Peach's message of Sun Apr 04 08:17:28 -0700 2010:
>   
>> On Sun, 4 Apr 2010 11:10:56 -0400
>> David Andersen  wrote:
>>
>> 
>>> There are some classical cases of assigning the same MAC address to every 
>>> machine in a batch, resetting the counter used to number them, etc.;  
>>> unless shown otherwise, these are likely to be errors, not accidental 
>>> collisions.
>>>
>>>   -Dave
>>>
>>> On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
>>>
>>>   
 I've seen duplicate addresses in the wild in the past, I assume there
 is some amount of reuse, even though they are suppose to be unique.

 -jim

 On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
 
> Hi,
>
> Lots of traffic recently about 64 bits being too short or too long.
>
> What about mac addresses? Aren't they close to exhaustion? Should be. Or 
> it
> is assumed that mac addresses are being widely reused throughout the 
> world?
> All those low cost switches and wifi adapters DO use unique mac addresses?
>
>   
>> Sun, for one, used to assign the same MAC address to every NIC in the
>> same box.
>> 
> I could see how that *could* work as long as each interface connected to
> a different LAN.
>   
That was a logic Sun used.  Every NIC would be connected to a different
subnet, so duplicate MACs shouldn't be a problem.  For the most part
this worked, but some situations required a unique MAC per NIC, and Sun
had a bit you could flip to turn this on.  I believe it was an OpenBoot
prom variable called "local-mac-address?" which you'd set to true if you
wanted it to use each NICs MAC instead of the "system MAC".

-Jim

Re: what about 48 bits?

[Scott Howard]

On Sun, Apr 4, 2010 at 1:51 PM, Matthew Kaufman  wrote:

> http://en.wikipedia.org/wiki/MAC_address
>>
>> The IEEE expects the MAC-48 space to be exhausted no sooner than the year
>> 2100[3]; EUI-64s are not expected to run out in the foreseeable future.
>>
>>
>
> And this is what happens when you can use 100% of the bits on "endpoint
> identity" and not waste huge sections of them on the decision bits for
> "routing topology".
>

Having around 4 orders of magnitude more addresses probably doesn't hurt
either...

Although even MAC-48 addresses are "wasteful" in that only 1/4 of them are
assignable to/by vendors, with the other 3/4 being assigned to multicast and
local addresses (the MAC equivalent of RFC1918)

  Scott.

Re: what about 48 bits?

[Matthew Kaufman]

Richard A Steenbergen wrote:

On Sun, Apr 04, 2010 at 11:53:54AM -0300, A.B. Jr. wrote:
  

Hi,

Lots of traffic recently about 64 bits being too short or too long.

What about mac addresses? Aren't they close to exhaustion? Should be.
Or it is assumed that mac addresses are being widely reused throughout
the world? All those low cost switches and wifi adapters DO use unique
mac addresses?



http://en.wikipedia.org/wiki/MAC_address

The IEEE expects the MAC-48 space to be exhausted no sooner than the 
year 2100[3]; EUI-64s are not expected to run out in the foreseeable 
future.


  
And this is what happens when you can use 100% of the bits on "endpoint 
identity" and not waste huge sections of them on the decision bits for 
"routing topology".


Of course it comes with a privacy problem if you want to use that 
endpoint identifier globally and not change it for every session (as 
some protocols that separate routable-address from endpoint-identity do)


Matthew Kaufman

Re: what about 48 bits?

[Richard A Steenbergen]

On Sun, Apr 04, 2010 at 11:53:54AM -0300, A.B. Jr. wrote:
> Hi,
> 
> Lots of traffic recently about 64 bits being too short or too long.
> 
> What about mac addresses? Aren't they close to exhaustion? Should be.
> Or it is assumed that mac addresses are being widely reused throughout
> the world? All those low cost switches and wifi adapters DO use unique
> mac addresses?

http://en.wikipedia.org/wiki/MAC_address

The IEEE expects the MAC-48 space to be exhausted no sooner than the 
year 2100[3]; EUI-64s are not expected to run out in the foreseeable 
future.

-- 
Richard A Steenbergenhttp://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)

Re: what about 48 bits?

[Steven Bellovin]

On Apr 4, 2010, at 11:46 17AM, Jonathan Lassoff wrote:

> Excerpts from John Peach's message of Sun Apr 04 08:17:28 -0700 2010:
>> On Sun, 4 Apr 2010 11:10:56 -0400
>> David Andersen  wrote:
>> 
>>> There are some classical cases of assigning the same MAC address to every 
>>> machine in a batch, resetting the counter used to number them, etc.;  
>>> unless shown otherwise, these are likely to be errors, not accidental 
>>> collisions.
>>> 
>>>  -Dave
>>> 
>>> On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
>>> 
 I've seen duplicate addresses in the wild in the past, I assume there
 is some amount of reuse, even though they are suppose to be unique.
 
 -jim
 
 On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
> Hi,
> 
> Lots of traffic recently about 64 bits being too short or too long.
> 
> What about mac addresses? Aren't they close to exhaustion? Should be. Or 
> it
> is assumed that mac addresses are being widely reused throughout the 
> world?
> All those low cost switches and wifi adapters DO use unique mac addresses?
> 
>> Sun, for one, used to assign the same MAC address to every NIC in the
>> same box.
> 
> I could see how that *could* work as long as each interface connected to
> a different LAN.
> 
> Maybe the NICs shared a single MII/MAC sublayer somehow? I've never
> borne witness to this though.

There was a socketed ROM IC with the *machine's* MAC address on the 
motherboard, way back when.  If your motherboard needed replacing, the tech 
would move that IC to the replacement.  

Why was this done?  The reason was simple: compatibility with other stacks.  
Remember that circa 1988-1990, it was not obvious that TCP/IP was going to be 
the winner.

--Steve Bellovin, http://www.cs.columbia.edu/~smb

Re: what about 48 bits?

[Mark Andrews]

In message <20100404111728.2b5c9...@milhouse.peachfamily.net>, John Peach 
writes:
> On Sun, 4 Apr 2010 11:10:56 -0400
> David Andersen  wrote:
> 
> > There are some classical cases of assigning the same MAC address to every 
> > machine in a batch, resetting the counter used to number them, etc.;  
> > unless shown otherwise, these are 
> likely to be errors, not accidental collisions.
> > 
> >   -Dave
> > 
> > On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
> > 
> > > I've seen duplicate addresses in the wild in the past, I assume there
> > > is some amount of reuse, even though they are suppose to be unique.
> > > 
> > > -jim
> > > 
> > > On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
> > >> Hi,
> > >> 
> > >> Lots of traffic recently about 64 bits being too short or too long.
> > >> 
> > >> What about mac addresses? Aren't they close to exhaustion? Should be. Or 
> > >> it
> > >> is assumed that mac addresses are being widely reused throughout the 
> > >> world?
> > >> All those low cost switches and wifi adapters DO use unique mac 
> > >> addresses?
> > >> 
> Sun, for one, used to assign the same MAC address to every NIC in the
> same box.

Which is perfectly legal.
> 
> -- 
> John
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org

Re: what about 48 bits?

[Jonathan Lassoff]

Excerpts from John Peach's message of Sun Apr 04 08:17:28 -0700 2010:
> On Sun, 4 Apr 2010 11:10:56 -0400
> David Andersen  wrote:
> 
> > There are some classical cases of assigning the same MAC address to every 
> > machine in a batch, resetting the counter used to number them, etc.;  
> > unless shown otherwise, these are likely to be errors, not accidental 
> > collisions.
> > 
> >   -Dave
> > 
> > On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
> > 
> > > I've seen duplicate addresses in the wild in the past, I assume there
> > > is some amount of reuse, even though they are suppose to be unique.
> > > 
> > > -jim
> > > 
> > > On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
> > >> Hi,
> > >> 
> > >> Lots of traffic recently about 64 bits being too short or too long.
> > >> 
> > >> What about mac addresses? Aren't they close to exhaustion? Should be. Or 
> > >> it
> > >> is assumed that mac addresses are being widely reused throughout the 
> > >> world?
> > >> All those low cost switches and wifi adapters DO use unique mac 
> > >> addresses?
> > >> 
> Sun, for one, used to assign the same MAC address to every NIC in the
> same box.

I could see how that *could* work as long as each interface connected to
a different LAN.

Maybe the NICs shared a single MII/MAC sublayer somehow? I've never
borne witness to this though.


Re: MAC address exhaustion, if the the second-to-least significant bit
in the first byte is 0 (Globally Unique / Individually Assigned bit),
then the first three bytes of the MAC should correspond to the
manufacturer's "Organizationally Unique Identifier". These are
maintained by the IEEE, and they have a list of who's who here:
http://standards.ieee.org/regauth/oui/index.shtml


I haven't ever programmatically gone through the list, but it looks like
a lot of the space is assigned.

Cheers,
jof

UETS/EFR (was Re: what about 48 bits?)

[William Duck]

http://www.lmdata.es/uets.htm


 Original Message 
Subject:what about 48 bits?
Date:   Sun, 4 Apr 2010 11:53:54 -0300
From:   A.B. Jr. 
To: nanog@nanog.org



Hi,

Lots of traffic recently about 64 bits being too short or too long.

What about mac addresses? Aren't they close to exhaustion? Should be. Or it
is assumed that mac addresses are being widely reused throughout the world?
All those low cost switches and wifi adapters DO use unique mac addresses?







_
Get your own *free* email address like this one from www.OwnEmail.com

Re: what about 48 bits?

[Mikael Abrahamsson]

On Sun, 4 Apr 2010, jim deleskie wrote:


I've seen duplicate addresses in the wild in the past, I assume there
is some amount of reuse, even though they are suppose to be unique.


5 percent of the mac addresses in a ADSL population used the same MAC 
address. Turned out to be some D-link device that didn't have unique 
address but they all had the same, and had a feature where you could 
"clone" the internal PC MAC address if you wanted to, otherwise it used 
some default address.


D-link support responded to customer inquiries with "yes, we know that 
they're not unique enough". Nuff said, avoid.


--
Mikael Abrahamssonemail: swm...@swm.pp.se

Re: what about 48 bits?

[William Herrin]

On Sun, Apr 4, 2010 at 11:17 AM, John Peach  wrote:
> Sun, for one, used to assign the same MAC address to every NIC in the
> same box.

Technically, they assigned a MAC to the NIC and a MAC to the box.
Unless you configured it otherwise, all NICs in the box defaulted to
using the box's MAC instead of their own.

Made for some interesting problems with early VLAN switches...

Regards,
Bill Herrin


-- 
William D. Herrin  her...@dirtside.com  b...@herrin.us
3005 Crane Dr. .. Web: 
Falls Church, VA 22042-3004

Re: what about 48 bits?

[John Peach]

On Sun, 4 Apr 2010 11:10:56 -0400
David Andersen  wrote:

> There are some classical cases of assigning the same MAC address to every 
> machine in a batch, resetting the counter used to number them, etc.;  unless 
> shown otherwise, these are likely to be errors, not accidental collisions.
> 
>   -Dave
> 
> On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
> 
> > I've seen duplicate addresses in the wild in the past, I assume there
> > is some amount of reuse, even though they are suppose to be unique.
> > 
> > -jim
> > 
> > On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
> >> Hi,
> >> 
> >> Lots of traffic recently about 64 bits being too short or too long.
> >> 
> >> What about mac addresses? Aren't they close to exhaustion? Should be. Or it
> >> is assumed that mac addresses are being widely reused throughout the world?
> >> All those low cost switches and wifi adapters DO use unique mac addresses?
> >> 
Sun, for one, used to assign the same MAC address to every NIC in the
same box.

-- 
John

Re: what about 48 bits?

[David Andersen]

There are some classical cases of assigning the same MAC address to every 
machine in a batch, resetting the counter used to number them, etc.;  unless 
shown otherwise, these are likely to be errors, not accidental collisions.

  -Dave

On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:

> I've seen duplicate addresses in the wild in the past, I assume there
> is some amount of reuse, even though they are suppose to be unique.
> 
> -jim
> 
> On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
>> Hi,
>> 
>> Lots of traffic recently about 64 bits being too short or too long.
>> 
>> What about mac addresses? Aren't they close to exhaustion? Should be. Or it
>> is assumed that mac addresses are being widely reused throughout the world?
>> All those low cost switches and wifi adapters DO use unique mac addresses?
>> 
> 
> 

Re: what about 48 bits?

[jim deleskie]

I've seen duplicate addresses in the wild in the past, I assume there
is some amount of reuse, even though they are suppose to be unique.

-jim

On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr.  wrote:
> Hi,
>
> Lots of traffic recently about 64 bits being too short or too long.
>
> What about mac addresses? Aren't they close to exhaustion? Should be. Or it
> is assumed that mac addresses are being widely reused throughout the world?
> All those low cost switches and wifi adapters DO use unique mac addresses?
>

what about 48 bits?

[A.B. Jr.]

Hi,

Lots of traffic recently about 64 bits being too short or too long.

What about mac addresses? Aren't they close to exhaustion? Should be. Or it
is assumed that mac addresses are being widely reused throughout the world?
All those low cost switches and wifi adapters DO use unique mac addresses?