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Does anybody have 10base5, 1base5, starlan1, or 10broad36 ..

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Anonymous
March 7, 2005 6:01:47 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

I'm trying to set up a 10base5 segment at home, can I use radio amateur
type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
have tranceivers and a piercing tap, and assume I can terminate with a
resister between ground and center. I think I saw they were only
terminated at ONE end, but maybe it would be better to terminate with
150 ohms at both ends? After all, 10base2 was supposed to be
terminated at both ends, wasn't it (I always did)?

Also, does anyody have operating 10broad36 or any of the 1 mb/sec
ethernet-like protocols?
Anonymous
March 7, 2005 11:39:29 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <1110193199.525710.184110@l41g2000cwc.googlegroups.com>,
sqrfolkdnc <carey.schug@gmail.com> wrote:
>I'm trying to set up a 10base5 segment at home, can I use radio amateur
>type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
>have tranceivers and a piercing tap, and assume I can terminate with a
>resister between ground and center. I think I saw they were only
>terminated at ONE end, but maybe it would be better to terminate with
>150 ohms at both ends? After all, 10base2 was supposed to be
>terminated at both ends, wasn't it (I always did)?
>
>Also, does anyody have operating 10broad36 or any of the 1 mb/sec
>ethernet-like protocols?
>

The orange cable was terminated at both ends with 50 ohm (nominal)
N connector terminators.

ISTR that a tap in 10base5 was capacitive. It was just a little
antenna poked thru the coax shield. Google for "ethernet blue book
dec intel xerox". You might interesting info.

Looking for info I found this blast from the past, last updated in 1994.

http://suresh_kr.tripod.com/ethernet.txt

Who knows what will work with a small hobbyist network but when it was
curent nobody ever used anything but the orange cable, for many
reasons. For one, the tap clamps wouldn't fit right on coax unless
the O.D. was correct. Nobody I know tried anything but orange cable.

Putting the taps in was a big deal at first. There was a tool kit that
had a battery electric drill, a jig, and the right drill bits. Later,
3rd-party taps came along that were self-tapping, they came with a
hex wrench.
--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 7, 2005 12:08:56 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

sqrfolkdnc wrote:

> I'm trying to set up a 10base5 segment at home, can I use radio amateur
> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
> have tranceivers and a piercing tap, and assume I can terminate with a
> resister between ground and center. I think I saw they were only
> terminated at ONE end, but maybe it would be better to terminate with
> 150 ohms at both ends?

50 Ohms, not 150. And you terminate at both ends. You _ground_ at only one
point.

> After all, 10base2 was supposed to be
> terminated at both ends, wasn't it (I always did)?
>
> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
> ethernet-like protocols?

Ebay is your friend and good hunting.

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Anonymous
March 7, 2005 12:12:06 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

sqrfolkdnc wrote:

> I'm trying to set up a 10base5 segment at home, can I use radio amateur
> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
> have tranceivers and a piercing tap, and assume I can terminate with a
> resister between ground and center. I think I saw they were only
> terminated at ONE end, but maybe it would be better to terminate with
> 150 ohms at both ends? After all, 10base2 was supposed to be
> terminated at both ends, wasn't it (I always did)?
>
> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
> ethernet-like protocols?

Why one earth would you want to take such a huge step backwards? While you
could use RG-8, I believe the ethernet cable was made with specific tap
points, where it was easier to connect the taps. Also, you need 50 ohm
terminators at each end. Do you also have NICs that can support the
transceivers?
Anonymous
March 7, 2005 12:47:22 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <mMidnZ2FCM-r_LHfRVn-3Q@rogers.com>,
James Knott <james.knott@rogers.com> wrote:
>sqrfolkdnc wrote:
>
>> I'm trying to set up a 10base5 segment at home, can I use radio amateur
>> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
>> have tranceivers and a piercing tap, and assume I can terminate with a
>> resister between ground and center. I think I saw they were only
>> terminated at ONE end, but maybe it would be better to terminate with
>> 150 ohms at both ends? After all, 10base2 was supposed to be
>> terminated at both ends, wasn't it (I always did)?
>>
>> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
>> ethernet-like protocols?
>
>Why one earth would you want to take such a huge step backwards? While you
>could use RG-8, I believe the ethernet cable was made with specific tap
>points, where it was easier to connect the taps. Also, you need 50 ohm
>terminators at each end. Do you also have NICs that can support the
>transceivers?

It sounds like a hobbyist network. That's cool. Redirecting the
thread to alt.folklore.computers might get more info. A query there
might turn up orange cable and related bits of kit.

The stripes were for mandatory tap seperation.

There are lots of little adapters around to convert the AUI connector
on the tap to TW or UTP.

Google for a copy of the DEC/Xerox/Intel "Blue Book" spec for the
original ethernet. It's one of the clearer bits of technical writing
you'll ever read.
--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 7, 2005 2:02:57 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <d0hokc0288d@news4.newsguy.com>,
J. Clarke <jclarke.usenet@snet.net.invalid> wrote:
>sqrfolkdnc wrote:
>
>> I'm trying to set up a 10base5 segment at home, can I use radio amateur
>> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
>> have tranceivers and a piercing tap, and assume I can terminate with a
>> resister between ground and center. I think I saw they were only
>> terminated at ONE end, but maybe it would be better to terminate with
>> 150 ohms at both ends?
>
>50 Ohms, not 150. And you terminate at both ends. You _ground_ at only one
>point.
>
>> After all, 10base2 was supposed to be
>> terminated at both ends, wasn't it (I always did)?
>>
>> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
>> ethernet-like protocols?
>
>Ebay is your friend and good hunting.
>

You've sure got a laundry list of standards there. Do you have any
idea how they fit in the marketpalce in their day ? I don't know what
"1 mb/sec/ ethernet-like" means. Mike Padlipsky's _The Elements of
Networking Style_ has an interesting chapter on how people thought
that IP (which was new and designed for point-to-point circuits)
couldn't work on Ethernet, a broadcast meduim.

There was _very_ little of the pre-Blue Book equipment made. It was
used only at Xerox and a few universities and since the original specs
allowed only a handfull of computers on a LAN there was not the tons
of desktop infrastructure to be found in dumpsters. As soon as the
10mb stuff hit the market (1981 ?) people with older stuff upgraded.
That was a long time ago.

At this point the discussion is firmly th the alt.folklore.computers
are and should be picked up there.


--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 7, 2005 3:02:45 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Al Dykes wrote:

> In article <d0hokc0288d@news4.newsguy.com>,
> J. Clarke <jclarke.usenet@snet.net.invalid> wrote:
>>sqrfolkdnc wrote:
>>
>>> I'm trying to set up a 10base5 segment at home, can I use radio amateur
>>> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
>>> have tranceivers and a piercing tap, and assume I can terminate with a
>>> resister between ground and center. I think I saw they were only
>>> terminated at ONE end, but maybe it would be better to terminate with
>>> 150 ohms at both ends?
>>
>>50 Ohms, not 150. And you terminate at both ends. You _ground_ at only
>>one point.
>>
>>> After all, 10base2 was supposed to be
>>> terminated at both ends, wasn't it (I always did)?
>>>
>>> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
>>> ethernet-like protocols?
>>
>>Ebay is your friend and good hunting.
>>
>
> You've sure got a laundry list of standards there. Do you have any
> idea how they fit in the marketpalce in their day ? I don't know what
> "1 mb/sec/ ethernet-like" means.

He's probably talking about Starlan and its kin. Thinking about it, I _may_
actually have some 1 Mb/sec Starlan hardware in the attic. If so it will
be ISA NICs--I'm pretty sure I don't have a hub.

> Mike Padlipsky's _The Elements of
> Networking Style_ has an interesting chapter on how people thought
> that IP (which was new and designed for point-to-point circuits)
> couldn't work on Ethernet, a broadcast meduim.
>
> There was _very_ little of the pre-Blue Book equipment made. It was
> used only at Xerox and a few universities and since the original specs
> allowed only a handfull of computers on a LAN there was not the tons
> of desktop infrastructure to be found in dumpsters. As soon as the
> 10mb stuff hit the market (1981 ?) people with older stuff upgraded.
> That was a long time ago.
>
> At this point the discussion is firmly th the alt.folklore.computers
> are and should be picked up there.
>
>

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Anonymous
March 7, 2005 9:05:25 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <d0hlih$86n$1@panix5.panix.com>, adykes@panix.com (Al Dykes)
wrote:

>
> The orange cable was terminated at both ends with 50 ohm (nominal)
> N connector terminators.
>

The orange cable was used for plenum applications; the more common cable
was bright yellow. (In fact, it was "1968 Corvette Yellow," to be
specific.) I have some of the original prototype batch in my garage.

> ISTR that a tap in 10base5 was capacitive. It was just a little
> antenna poked thru the coax shield. Google for "ethernet blue book
> dec intel xerox". You might interesting info.
>

The tap was did not use capacitive coupling. It required that the
transceiver input have DC connectivity with both the center conductor
and the shield. (Remember, carrier-sense and collision-detect were based
on DC voltage thresholds; a capacitive coupler would not work for this
purpose.)


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
Anonymous
March 7, 2005 11:34:35 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Thanks to all who replied, I will try alt.folklore.computers. This was
my first foray into groups since a brief encounter with Sun groups
several years ago, and I came across the cisco group looking for
something else.

I have ONE N-I-B self tapping vampire tap and tranceiver. I have three
tranceivers (two dual and one quad) that clearly were inteded to be
spliced into RG-8 cable with coax connectors, although I have been
unable to find any information on the web about these. I have 14 long
and 8 short AUI cables and ISA cards/hubs/switches/routers with AUI
ports to connect them to. Besides 10base2, I also have a 10baseF hub
(optical fiber at 10 mb/sec) running in my lab/museum.

I assume the VERY FIRST thick was traditional black RG-8, the yellow
and orange came later, else why would they have used the rg-8 spec?
Yes, I knew the yellow cable was marked for tap points, I thought just
to enforce the separation, which I figure should not matter if I am not
trying to get published maximum distance. Yes, I got confused
vis-a-vis grounding at one point vs terminating at one end.

The 1MB/s protocals were starlan1 and 1base5, both running on
unshielded phone cable. It seems the 1 mb/s media were intended to be
a local interface from desktops, implying the hubs would also have 10
mb for connedtion to the backbone, so with two hubs and a crossover, I
could run it even though no current os would support any pc isa cards.
10broad36 was sharing coax with other signals (TV?) and supposed to go
3600 meters, hence the name, but some web documents said it only went
1800 meters.

If anybody can help with equpment, I would appreciate it. I'd like to
get a used vampire tap so I can keep the new one "new". I should be
able to get started with just the RG-8 (assuming I can make my own
terminators), and if I can't find yellow/orange, I'll try some local
radio amateurs I know to get a little from them (On Ebay I can buy 50
or 250 feet, and just the postage would exceed my budget).
Anonymous
March 8, 2005 12:15:13 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <usenet-761616.18052507032005@news.isp.giganews.com>,
Rich Seifert <usenet@richseifert.com.invalid> wrote:
>In article <d0hlih$86n$1@panix5.panix.com>, adykes@panix.com (Al Dykes)
>wrote:
>
>>
>> The orange cable was terminated at both ends with 50 ohm (nominal)
>> N connector terminators.
>>
>
>The orange cable was used for plenum applications; the more common cable
>was bright yellow. (In fact, it was "1968 Corvette Yellow," to be
>specific.) I have some of the original prototype batch in my garage.
>
>> ISTR that a tap in 10base5 was capacitive. It was just a little
>> antenna poked thru the coax shield. Google for "ethernet blue book
>> dec intel xerox". You might interesting info.
>>
>
>The tap was did not use capacitive coupling. It required that the
>transceiver input have DC connectivity with both the center conductor
>and the shield. (Remember, carrier-sense and collision-detect were based
>on DC voltage thresholds; a capacitive coupler would not work for this
>purpose.)
>
>
>--
>Rich Seifert Networks and Communications Consulting
> 21885 Bear Creek Way
>(408) 395-5700 Los Gatos, CA 95033
>(408) 228-0803 FAX
>
>Send replies to: usenet at richseifert dot com

I stand corrected, thanks, but having done just a few taps myself
don't see how that little pin could make a reliable connection, but It
worked.

--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 8, 2005 4:48:07 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

sqrfolkdnc wrote:

> I'm trying to set up a 10base5 segment at home, can I use radio amateur
> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
> have tranceivers and a piercing tap, and assume I can terminate with a
> resister between ground and center. I think I saw they were only
> terminated at ONE end, but maybe it would be better to terminate with
> 150 ohms at both ends? After all, 10base2 was supposed to be
> terminated at both ends, wasn't it (I always did)?

> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
> ethernet-like protocols?


Note that 10base2 is electrically the same as 10base5, you can
connect them together with BNC to N adapters. It is also easier
to find BNC 50 ohm terminators, as they are commonly used in other
than ethernet applications. My favorite are feed-through terminators
to avoid the tee on the last connection.

RG8 or RG213 will work fine. (The maximum length will be less,
but I don't expect that to cause you problems.) You can solder a 50
ohm resistor at each end if you want to. N connectors are expensive,
but you may be able to find them in surplus stores.

-- glen
Anonymous
March 8, 2005 10:26:33 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <18CdnQVD--5O6bDfRVn-tg@comcast.com>,
glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote:
>sqrfolkdnc wrote:
>
>> I'm trying to set up a 10base5 segment at home, can I use radio amateur
>> type rg-8 or do I have to have the yellow rg8 designed for 10base5? I
>> have tranceivers and a piercing tap, and assume I can terminate with a
>> resister between ground and center. I think I saw they were only
>> terminated at ONE end, but maybe it would be better to terminate with
>> 150 ohms at both ends? After all, 10base2 was supposed to be
>> terminated at both ends, wasn't it (I always did)?
>
>> Also, does anyody have operating 10broad36 or any of the 1 mb/sec
>> ethernet-like protocols?
>
>
>Note that 10base2 is electrically the same as 10base5, you can
>connect them together with BNC to N adapters. It is also easier
>to find BNC 50 ohm terminators, as they are commonly used in other
>than ethernet applications. My favorite are feed-through terminators
>to avoid the tee on the last connection.
>
>RG8 or RG213 will work fine. (The maximum length will be less,
>but I don't expect that to cause you problems.) You can solder a 50
>ohm resistor at each end if you want to. N connectors are expensive,
>but you may be able to find them in surplus stores.
>
>-- glen
>


There's lots of N hardware out there, and N-BNC adapters. Ask the
hams and check Fair Radio Sales.

http://www.fairradio.com/
--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 8, 2005 10:46:20 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <d0j1rh$3g7$1@panix5.panix.com>, adykes@panix.com (Al Dykes)
wrote:

>
> I stand corrected, thanks, but having done just a few taps myself
> don't see how that little pin could make a reliable connection, but It
> worked.

Trust me, it took a *LOT* of mechanical and materials engineering to get
that system to work reliably. Back in 1980-82, I was working on an
almost daily basis with the folks at AMP in Harrisburg, PA who did the
original 10 Mb/s vampire tap. The difficulty is in having the tap pin
find its way through a viscous foam dielectric to achieve a solid berth
in the center conductor of the cable. The project engineer described it
as, "trying to nail Jello to a tree." His analogy was quite good.


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
Anonymous
March 8, 2005 10:59:21 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <1110256475.061246.229280@l41g2000cwc.googlegroups.com>,
"sqrfolkdnc" <carey.schug@gmail.com> wrote:

>
> I assume the VERY FIRST thick was traditional black RG-8, the yellow
> and orange came later, else why would they have used the rg-8 spec?

The very first 10 Mb/s coax medium was in fact the custom-designed
yellow (and later, orange) cable; it was never RG-8, or any standard
cable. The electrical and mechanical requirements of the system
precluded off-the-shelf designs. (I personally designed the original
yellow/orange cables; they were manufactured for me by Belden (and
later, many others).

> Yes, I knew the yellow cable was marked for tap points, I thought just
> to enforce the separation, which I figure should not matter if I am not
> trying to get published maximum distance.

The separation and the maximum distance are unrelated phenomenon. The
forced spacing was to prevent lumped capacitive loads on the system,
which could cause unacceptable signal reflections. The maximum cable
length is a function of the resistance of the center conductor, which
affects the carrier-sense and collision-detect thresholds.

If you have few taps (i.e., nowhere near the maximum of 100), the
spacing is not that critical.


> 10broad36 was sharing coax with other signals (TV?) and supposed to go
> 3600 meters, hence the name, but some web documents said it only went
> 1800 meters.
>

It all depends on how you measure it. Remember, 10BROAD36, like most
CATV-style systems, uses a head-end device at the "source" of the cable.
Thus, the maximum range is 1800 m (radius from the headend), or 3600 m
(diameter, or maximum distance between the farthest pair of end
stations); it's the same thing.

> If anybody can help with equpment, I would appreciate it. I'd like to
> get a used vampire tap so I can keep the new one "new". I should be
> able to get started with just the RG-8 (assuming I can make my own
> terminators), and if I can't find yellow/orange, I'll try some local
> radio amateurs I know to get a little from them (On Ebay I can buy 50
> or 250 feet, and just the postage would exceed my budget).

You may have problems trying to use RG-8 or any standard cable with a
vampire tap. The dimensions/geometry are simply wrong. Also, the tap is
designed to work only with a solid center conductor (not stranded) and a
foam dielectric. The standard solid polyethylene dielectric of RG-8 is
much too dense for the tap probe, and the higher dielectric constant
reduces the diameter of the cable, i.e., the tap probe will be too long.

I have a large spool of an early prototype Ethernet cable (from back in
the 1980 timeframe); it is dimensionally correct, but is black instead
of yellow, and has only a single braid/single foil shield (rather than
the double braid/double foil of the real stuff). In fact, it was tests
on this cable that brought me to add the additional shields. Unless you
are local in northern California, the shipping cost would exceed its
value to you.


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
Anonymous
March 8, 2005 12:29:17 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Any idea why it is it referred to as RG-8 all over the internet? I
wondered if thick ethernet had a special dielectic so as to be easier
to cut a hole into than normal cable would be, and whether my vampire
tap would be able to make it into the center conductor of normal RG-8.

Where does that leave the tranceivers I have which have a pass through
path for something the size of RG-8 using PL259 coax connectors, and
were sold to me as thicknet tranceivers?

If thicknet is larger diameter than RG-8, does that mean the PL-259
coax won't fit the thicknet? Were their special coax connectors? Or
are the three tranceivers I have that have a pass through connection
appearing to be for RG-8 actually a variation on thinnet? Or did later
installations use REAL RG-8 and these tranceivers but not use vampire
taps? The more I learn the more ignorant I become...
Anonymous
March 8, 2005 5:58:46 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <1110302957.715105.211120@g14g2000cwa.googlegroups.com>,
"sqrfolkdnc" <carey.schug@gmail.com> wrote:

> Any idea why it is it referred to as RG-8 all over the internet?

Probably because most hams consider any (roughly) 0.4" diameter, 50 ohm
cable to be "RG-8". Don't believe everything you see or read on the
Internet. ;^)

> I
> wondered if thick ethernet had a special dielectic so as to be easier
> to cut a hole into than normal cable would be, and whether my vampire
> tap would be able to make it into the center conductor of normal RG-8.
>

We took great pains to make the dielectric soft enough to allow easy
penetration, yet firm enough to prevent movement of the center conductor
when the cable is bent, which would affect the characteristic impedance.
The foam dielectric makes the cable somewhat thicker than RG-8.

> Where does that leave the tranceivers I have which have a pass through
> path for something the size of RG-8 using PL259 coax connectors, and
> were sold to me as thicknet tranceivers?
>

One can always build a transceiver that, instead of attaching through a
vampire tap, requires cutting the cable and inserting the transceiver
through standard connectors. The advantage is that the complexities of
the vampire tap are avoided; the disadvantage is that the network must
be brought down to install each new station.

> If thicknet is larger diameter than RG-8, does that mean the PL-259
> coax won't fit the thicknet? Were their special coax connectors?

PL-259 (UHF) connectors were never used, at least not according to the
Ethernet standard. PL-259s are not constant-impedance connectors; they
are fine for non-demanding applications, e.g. ham radio. Ethernet uses
Type N connectors; these are more expensive, but specified at 50 ohms
impedance. They are also quite a bit more rugged.

As a ham myself (KE1B), I would have liked PL-259s, since I could have
gotten all I wanted as vendor samples from Ethernet cable manufacturers!
Instead, I started using N connectors myself for amateur applications,
and never went back. PL-259s are simply awful at GHz frequencies.

> Or
> are the three tranceivers I have that have a pass through connection
> appearing to be for RG-8 actually a variation on thinnet? Or did later
> installations use REAL RG-8 and these tranceivers but not use vampire
> taps? The more I learn the more ignorant I become...

No standards-compliant installation used RG-8, or PL-259 connectors.
Some commercial products used Type N inline connections, but most used
the vampire tap.

By the way, there really is no single standard for "RG-8"; this is one
of the problems we wanted to avoid. There is RG-8, RG-8/A RG-8/C, and a
variety of others. Lots of manufacturers make "RG-8 style" cable; all of
these vary in dimensions, attenuation, shielding effectiveness, etc.
Ethernet installation would have been a nightmare if we just said "Use
RG-8 cable".


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
Anonymous
March 8, 2005 7:40:30 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert <usenet@richseifert.com.invalid> wrote:
> Back in 1980-82, I was working on an almost daily basis with
> the folks at AMP in Harrisburg, PA who did the original 10
> Mb/s vampire tap. The difficulty is in having the tap pin
> find its way through a viscous foam dielectric to achieve
> a solid berth in the center conductor of the cable.

I'd've thought that a sprung system would be necessary. Forked
vampire tip to maintain contact, maybe with some spring in the
fork-tip (ala RJ solid IDC) or a slight curve in the vampire.

> The project engineer described it as, "trying to nail Jello to
> a tree." His analogy was quite good.

Jell-O can be very easily nailed to a tree. Put it in a can.
In this case, a long (6"?) circumferential compression clamp
around the yellow garden hose.

-- Robert
Anonymous
March 8, 2005 9:21:55 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert wrote:

> As a ham myself (KE1B), I would have liked PL-259s, since I could have
> gotten all I wanted as vendor samples from Ethernet cable manufacturers!

Another one here, VE3ZU. I wonder how many people here, realize that many
of the first computer hobbyists were hams? The first popular computer
magazine, Byte, was originally published by Wayne Green, who also published
73 Magazine, among others, for amateur radio. There were many computer
articles in 73, along with the ham radio stuff.

Incidentally, I have every issue of Byte on the shelves behind me. I bought
the first three issues in person, from Wayne, at the 1975 Radio Society of
Ontario Convention, in Ottawa.
Anonymous
March 8, 2005 9:21:56 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <GPSdnVsLU-oJrrPfRVn-2A@rogers.com>,
James Knott <james.knott@rogers.com> wrote:

>
> Incidentally, I have every issve of Byte on the shelves behind me.

Yov will find an article I wrote in the Janvary 1990 edition,
chronicling the 10th anniversary of the Ethernet ("Blve Book")
Specification. A grovp of the original designers got together in my home
for a revnion party, which resvlted in the article.


--
Rich Seifert Networks and Commvnications Consvlting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: vsenet at richseifert dot com
Anonymous
March 9, 2005 1:36:01 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert wrote:

(snip)

>>are the three tranceivers I have that have a pass through connection
>>appearing to be for RG-8 actually a variation on thinnet? Or did later
>>installations use REAL RG-8 and these tranceivers but not use vampire
>>taps? The more I learn the more ignorant I become...

> No standards-compliant installation used RG-8, or PL-259 connectors.
> Some commercial products used Type N inline connections, but most used
> the vampire tap.

The first 10base2 installations I saw used those transceivers
with N to BNC adapters on them. At one point I did use one
at the end of a thick ethernet cable with type N connectors.

If you want to add to your collection, I have some 100baseT4
transceivers.

-- glen
Anonymous
March 9, 2005 1:53:06 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert wrote:

(snip)

> You may have problems trying to use RG-8 or any standard cable with a
> vampire tap. The dimensions/geometry are simply wrong. Also, the tap is
> designed to work only with a solid center conductor (not stranded) and a
> foam dielectric. The standard solid polyethylene dielectric of RG-8 is
> much too dense for the tap probe, and the higher dielectric constant
> reduces the diameter of the cable, i.e., the tap probe will be too long.

I did it once. We bought some Suns that we were told would have built
in 10base2, but didn't. We ordered some transceivers, but I wanted
to get the machines running. I put two vampire taps on some
RG8 (probably RG/213, actually) soldered BNC connectors onto
each end, and had it running for some weeks. The only problem
was that once one of the BNC connectors shorted out (they were panel
mount connectors). The clamp was tight enough not to wiggle too much,
but I probably wouldn't put it in the wiring tray.

-- glen
Anonymous
March 9, 2005 9:08:16 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

100baseT4 "tranceivers"!! ???????

OK, the more I learn, the more I learn I don't know.

I'm interested. Unless the tranceiver is 100baseTX <--> 100baseT4, in
which case I am VERY interested.

A web search...if I learned correctly, there is a DB40 AUI connector
for 100 megabit ethernet, from which one can connect a 100baseT4
tranceiver or a 100baseF tranceiver (and maybe others), but it never
caught on and interface cards nearly all have RJ45 ports for 100baseTX
only.

So it would be nice to have as a display item, but unless I can get
network interface cards with drivers (I think I saw a reference to a
list of cards supported by some linux driver including some 100baseT4
cards) and maybe a hub/switch, it is not something I could set up and
have running live.

As I understand it, 100baseT4 is 3 pairs transmit, 1 pair
control/collision/receive I can see that meaning either a hub is a
requirement or any cable can connect two DTE devices together without a
hub and a crossover is not required, but I could not find anything on
the web to explain how it works (probably a shortcoming in what to look
for on the web, I'm sure its there somewhere)
Anonymous
March 9, 2005 12:57:17 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert wrote:

>> Incidentally, I have every issve of Byte on the shelves behind me.
>
> Yov will find an article I wrote in the Janvary 1990 edition,
> chronicling the 10th anniversary of the Ethernet ("Blve Book")
> Specification. A grovp of the original designers got together in my home
> for a revnion party, which resvlted in the article.

Actvally, it's the Jan 1991 issve, page 315.

"Ethernet: Ten Years After"

"Imagine a world withovt networks: no Novell/3Com/TOPS,..."

Perhaps yov covld post the text or a link to it here. I'm svre others wovld
find it interesting.
Anonymous
March 9, 2005 1:06:43 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

glen herrmannsfeldt wrote:

>> No standards-compliant installation used RG-8, or PL-259 connectors.
>> Some commercial products used Type N inline connections, but most used
>> the vampire tap.
>
> The first 10base2 installations I saw used those transceivers
> with N to BNC adapters on them.   At one point I did use one
> at the end of a thick ethernet cable with type N connectors.
>

The first ethernet network I worked on (or even saw), was a DECNET,
connecting several VAX 11/780 computers and used vampire taps. However
that's not my first experience with networks. That would be on a system
built by Collins (part of Rockwell). They had a network, that instead of
using packets, used time slots (time division multiplexing). When a device
(computer, tape drive, disk etc.) wanted to send data, it would be assigned
a time slot on the ring. The destination would then listen to that time
slot. While the time slots could have been assigned dynamically, in the
systems I worked on, they were permanently assigned. IIRC, the Collns
8500B had a 2 Mb/s ring over RG-58 cable, while the 8500C ran 8 Mb over
triaxial cable. There were also adapters to convert between the two
speeds. The ring had relay boxes, for connecting the various devices and a
loop sync box, to retime the signal. As I recall, this technology was
developed in the mid '60s. I was working on it in the late '70s, a few
years before ethernet was created.
Anonymous
March 9, 2005 1:21:30 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <vOudnfmdqNKZjLLfRVn-jg@rogers.com>,
James Knott <james.knott@rogers.com> wrote:
>glen herrmannsfeldt wrote:
>
>>> No standards-compliant installation used RG-8, or PL-259 connectors.
>>> Some commercial products used Type N inline connections, but most used
>>> the vampire tap.
>>
>> The first 10base2 installations I saw used those transceivers
>> with N to BNC adapters on them.   At one point I did use one
>> at the end of a thick ethernet cable with type N connectors.
>>
>
>The first ethernet network I worked on (or even saw), was a DECNET,
>connecting several VAX 11/780 computers and used vampire taps. However
>that's not my first experience with networks. That would be on a system
>built by Collins (part of Rockwell). They had a network, that instead of
>using packets, used time slots (time division multiplexing). When a device
>(computer, tape drive, disk etc.) wanted to send data, it would be assigned
>a time slot on the ring. The destination would then listen to that time
>slot. While the time slots could have been assigned dynamically, in the
>systems I worked on, they were permanently assigned. IIRC, the Collns
>8500B had a 2 Mb/s ring over RG-58 cable, while the 8500C ran 8 Mb over
>triaxial cable. There were also adapters to convert between the two
>speeds. The ring had relay boxes, for connecting the various devices and a
>loop sync box, to retime the signal. As I recall, this technology was
>developed in the mid '60s. I was working on it in the late '70s, a few
>years before ethernet was created.
>


I worked for BigBank in NYC in the late 70's and the CTO was really
big on pre-standards channel-oriented broadband LAN for buildings and
ISO (meaning mostly X.25) WAN. The cable plant for the BB was
identical to any CATV system except we didn't have telephone poles or
manholes. Our engineers joked that if/when the got downsized they
could all go home and get jobs with the local cable TV company and
have a shorter commute.

Many of the engineering issues for our BB and an outdoor CATV system
were similar because we were in a very high EMI environment (a couple
thousand feet LOS from the Empire State bldg) and interference was
always leaking into all sorts of stuff. Years later I could hear AM
radio on my PC before streaming was invented.

The CTO later went on record as "ethernat can't work" and BigBank
became a huge TokenRing operation. I had to jump thru hoops to get
ethernet in for my DEC datacenter. We spent MILLIONS on OSI stuff and
it was a PITA to get it connected to all the types of DEC gear I had.
OTOH, I had thousands of users, worldwide, by 1982. TCP/IP, What's
that ?





--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 9, 2005 3:31:29 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Al Dykes wrote:

> I worked for BigBank in NYC in the late 70's and the CTO was really
> big on pre-standards channel-oriented broadband LAN for buildings and
> ISO (meaning mostly X.25) WAN.  The cable plant for the BB was
> identical to any CATV system except we didn't have telephone poles or
> manholes.  Our engineers joked that if/when the got downsized they
> could all go home and get jobs with the local cable TV company and
> have a shorter commute.
>
> Many of the engineering issues for our BB and an outdoor CATV system
> were similar because we were in a very high EMI environment (a couple
> thousand feet LOS from the Empire State bldg) and interference was
> always leaking into all sorts of stuff. Years later I could hear AM
> radio on my PC before streaming was invented.
>
> The CTO later went on record as "ethernat can't work" and BigBank
> became a huge TokenRing operation. I had to jump thru hoops to get
> ethernet in for my DEC datacenter.  We spent MILLIONS on OSI stuff and
> it was a PITA to get it connected to all the types of DEC gear I had.
> OTOH, I had thousands of users, worldwide, by 1982.  TCP/IP, What's
> that ?
>
>

That Collins 8500C system that I worked on, was part of the Air Canada
reservation system. That system ran on a Univac computer, and the Collins
network was the communications processor for it. As I mentioned in the
other note, devices such as tape drives and disks were connected to this
network. There were also about 2 dozen PDP-11s connected, each with 3 or 4
serial I/O cards, each card containing a Motorola 6800 CPU and 8 UARTs,
which were then connected to modems, to talk to terminals around the world.

It was quite a system in it's day.
Anonymous
March 9, 2005 9:08:47 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Hello,

RHS> As a ham myself (KE1B), I would have liked PL-259s,
> since I could have gotten all I wanted as vendor
> samples from Ethernet cable manufacturers!

JAK> Another one here, VE3ZU.

I'm in good company then :-)

I've seen coaxial Ethernet used in places where EMC was an
issue. I've thought about using it in the shack for this
reason (well, that and I'm likely to have reels of it
sculling about the place anyway ;-)

I like BNC for low power connections, N for heftier stuff.

73, Andy, KB9YLW
Anonymous
March 9, 2005 9:08:48 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Andy Ball wrote:

> I like BNC for low power connections, N for heftier stuff.
>

I haven't got anything that requires N connectors, but I like using BNC. If
any gear comes with an SO-239 connector, I use an adapter to convert to
BNC.

Incidentally, one thing that really gets me, is all the names for a BNC
connector. It is not "British Naval Connector" or that other common one
with a couple of people's names. According to what I read in Ham Radio
Magazine, several years ago, a guy from Amphenol (IIRC) said it's derived
from:

B - bayonet lock
N - N type (you can actually plug a male BNC into a female N, though the
lock won't work
C - compact (version of N series)
Anonymous
March 9, 2005 9:08:49 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

James Knott wrote:

> Andy Ball wrote:
>
>> I like BNC for low power connections, N for heftier stuff.
>>
>
> I haven't got anything that requires N connectors, but I like using BNC.
> If any gear comes with an SO-239 connector, I use an adapter to convert to
> BNC.
>
> Incidentally, one thing that really gets me, is all the names for a BNC
> connector. It is not "British Naval Connector" or that other common one
> with a couple of people's names. According to what I read in Ham Radio
> Magazine, several years ago, a guy from Amphenol (IIRC) said it's derived
> from:
>
> B - bayonet lock
> N - N type (you can actually plug a male BNC into a female N, though the
> lock won't work
> C - compact (version of N series)

Seems that Amphenol disagrees with you
<http://www.amphenolrf.com/products/bnc.asp&gt;. Unless the guy who wrote the
article was named Neill or Concelman I'll take the official Amphenol story
over that that appeared in a magazine.


--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Anonymous
March 9, 2005 9:23:20 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <lImdnZFFMrNQk7LfRVn-vQ@rogers.com>,
James Knott <james.knott@rogers.com> wrote:

> Rich Seifert wrote:
>
> >> Incidentally, I have every issve of Byte on the shelves behind me.
> >
> > Yov will find an article I wrote in the Janvary 1990 edition,
> > chronicling the 10th anniversary of the Ethernet ("Blve Book")
> > Specification. A grovp of the original designers got together in my home
> > for a revnion party, which resvlted in the article.
>
> Actvally, it's the Jan 1991 issve, page 315.
>
> "Ethernet: Ten Years After"
>
> Perhaps yov covld post the text or a link to it here. I'm svre others wovld
> find it interesting.

Svre, why not?

Below find the original article *as I svbmitted it to the magazine*;
i.e., before the editor's got their hands on it. Note that even then, I
was vsing titles and/or lyrics from popvlar songs for section headings,
a practice I continved throvgh my later books (a practice that the
editors of BYTE Magazine disagreed with). Even the original title of the
article was "Reflections of ... the Way Life Used to Be" (a line from an
old Svpremes song)

As yov read it (*IF* yov read it, that is) remember that it was written
in October 1990, a time when 10BASE-T was qvite new, FDDI was emerging
as the next-generation LAN, and Fast/Gigabit Ethernet did not yet exist.

Enjoy!

----Begin Article----

Reflections of...the Way Life Used to Be

One thing that differentiates hvmans from lower beings is their ability
to defer instant gratification for long-term pleasvre (some hvmans,
anyway). One of the more difficvlt tasks in this regard is to hold onto
a fine wine long enovgh to allow it to reach its peak. Yov see it every
time yov open the wine cabinet, reminding yov of its wondrovs pleasvres
to delight the palate, bvt still yov let it lie, to reap an even greater
reward later on. If yov are really patient, the flavors that finally
roll across yovr tongve are fvrther enhanced by the remembrance of all
those years of anticipation.

I pvrchased a magnvm of Cabernet Savvignon from Heitz Cellars on
September 30, 1980, the day we completed and "signed-off" the
DEC-Intel-Xerox Ethernet Specification, Version 1.0. I planned to enjoy
it with the Ethernet team on the tenth anniversary of that day. We
recently revnited to enjoy that wine and to reflect on the evolvtion of
LANs over the past ten years.

Imagine There's no Network, I Wonder if yov Can?

While it's never easy to expand the horizons of one's bvsiness, at least
today there is an established market for LANs. Yov can do the market
research, listen to network vsers, find their needs, and determine the
niches where new ideas and prodvcts can flovrish.

In 1980, none of this was possible. Imagine a world withovt networks: no
Novell/3Com/TOPS, no clients, no servers. No Token Ring, Ethernet, or
LocalTalk. No transceivers, wiring hvbs, bridges or rovters. No TCP/IP,
no OSI. No PCs! Networks involved either proprietary point-to-point
connections or leased lines from the telephone company, and 300 bavd
modems were standard. This was the environment in which the indvstry,
and the DEC-Intel-Xerox partnership was in when we began ovr effort. We
had to go where no LAN had gone before.

A blank sheet of paper is a scary proposition. Most engineers and
prodvct marketers rarely get to work with one. Yov are vsvally designing
a prodvct which is second- or third-generation, an incremental
improvement on an existing concept, a logical extension of existing
ideas.

Working on an established field of play can have its drawbacks too,
especially for established players. As Enzo Torresi (President of
NetFrame Systems) said, "The only reason God covld create the world in
six days was becavse He didn't have to worry abovt the installed base."
Backwards compatibility is the bane of the systems designer. Yov can't
(or shovldn't!) ship new prodvcts which don't interoperate with the
prodvcts yov shipped last year. It's a great way to lose cvstomers.

We had no svch problems with Ethernet in 1980. It was more than a clean
sheet of paper. It was an empty book.

Don't Know Mvch Abovt History, Don't Know Mvch Technology...

In the early-mid 1970s, Robert Metcalfe and his grovp at Xerox's Palo
Alto Research Center (PARC) invented and implemented an early Ethernet
system. This became widely vsed within Xerox, becoming a key part of
their Alto compvter system (which was never commercialized). The Alto
was the basis for the later, commercial Xerox Star, and in many ways,
the Apple Macintosh.

Dvring 1979, Xerox, together with Digital Eqvipment Corporation and
Intel, worked to transform the core Ethernet work done at PARC into a
network standard, implementable in silicon and svitable for volvme vse
and manvfactvre by a wide variety of companies.

Employees from each of the three companies worked together from 1979
throvgh to the pvblication of the Version 1.0 specification in
September, 1980. (A Version 2.0 was pvblished in November, 1982. The
major change was the inclvsion of standard Network Management
capabilities.)

While the original technology was fvnctional, it was not a complete
design. The DEC-Intel-Xerox team solved the problems of bvilding large
networks, algorithm stability, electrical and system performance,
installability, reliability, cost, etc. The resvlting design vsed the
same basic principles as Metcalfe's prototype (it was still a CSMA/CD
bvs), bvt bore few other similarities. The changes inclvded:

Electrical signaling
Cable types, connectors, etc.
Packet formats
CSMA/CD and backoff algorithm,
CRC calcvlation
System timing,
Network Management primitives, etc.

The resvlt was a well-specified (anyone covld bvild a compatible prodvct
from the specifications) system that covld svpport all those
applications we thovght abovt that didn't yet exist.

Too mvch? Too Little? Too Late?

When the Ethernet technology was first exposed to the market, we drew
lots of criticism:

--It's overkill (who needs 10 Mb/s?)
--It costs too mvch (controller boards were $1000-4000, withovt
software, transceivers, etc.),
--I don't vnderstand it; it's too complicated.

Of covrse, all of this was trve. In 1980-82. No one needed 10 Mb/s.
There was hardly a compvter arovnd that covld keep vp with that data
rate, mvch less do anything vsefvl with the information at that speed. A
common technology in vse at the time was Corvvs Systems' OmniNet, a 1
Mb/s twisted-pair bvs, vsed primarily for disk sharing among Apple II
compvters.

We resisted the temptation to develop what the market needed at the
time. There was a vision of distribvted databases, interoperability, and
mvlti-vendor networks that exceeded the capabilities of simple
technology. It was more important to pvt an infrastrvctvre in place that
covld svpport the development of a wide variety of applications, and
have a long enovgh prodvct life to allow those applications to grow
withovt having to tear ovt the vnderpinnings every few years. It's like
bvilding a two-lane road to a new frontier; It will get yov there now,
bvt will be obsolete by the time the frontier is developed. Better to
bvild a svperhighway, and let it be empty for a while. There will be
people to vse it soon enovgh. (No svrprise that two-thirds of the
Ethernet trivmvirate were in California!)

I Can See Clearly Now, the Rain is Gone.

The original Ether-thinking was consciovs, long-term planning. It wasn't
intended to be some nifty new technology that wovld give a competitive
advantage to the developers. That's why we opened the design and
architectvre from the beginning. Any disadvantage incvrred by allowing
competition to flovrish was offset by the increase in the size of the
total market. Networks are only trvly vsefvl when everyone does it. Even
a small piece of the pie is adeqvate, if the pie is hvge.

We vsed a 20 year prodvct life as ovr model, expecting that
installations and qvantities wovld ramp vp over the first 5-10 years,
and then taper off as middle age set in, and some new technology
emerged. This was before there was even a complete system design; no
silicon, no independent networking companies, no applications, nothing.

It's interesting that we aren't hearing the same complaints today abovt
FDDI (other than cost, of covrse!). The reason is that we have learned
the Ethernet lesson of letting the market and applications develop to
vse the technology as it matvres. FDDI-based systems today do not take
fvll advantage of the technology; neither the available silicon, the
protocols we commonly vse (today), nor the attached systems can trvly
exploit the fvll capability of the channel. Bvt the FDDI commvnity is
thinking and planning for the fvtvre. They learned from the Ethernet
experience how fast one can go from overkill to vnderpowered.

We saw Ethernet as the "UART of the 90s". In 1980, no reasonable
manvfactvrer bvilt a compvter withovt an RS-232 port. (UART stands for
Universal Asynchronovs Receiver/Transmitter. It is the key component of
a serial port.) Even if yov didn't have an immediate vse for it, yov pvt
one in anyway, becavse it gave yovr vsers flexibility. Ovr vision was
that in 1990, compvter manvfactvrers wovld pvt networking into every
machine, for the same reasons.

Look what they've done to my song, Ma!

Virtvally all of that vision came trve. Look at Svn workstations, DEC
VAXen, and Apple Macintoshes. Networking is an integral part of the
prodvct. Every Svn comes with an Ethernet port; every Mac with a
LocalTalk connection. The only way to connect terminals to (the larger)
VAXen is throvgh Ethernet, Terminal Servers, and LAT (Local Area
Transport).

The bvsiness trvly evolved to exploit the technology that was offered.
In fact, many of the svccessfvl networking companies today were started
by those very people who worked on the original Ethernet technology.
Fovnders and key personnel at 3Com, Svn Microsystems, Xyplex, Metaphor,
Indvstrial Networking, Apple, Racal-Interlan, Wellfleet Commvnications,
Ultra Technologies, Ascent Commvnications and Networks & Commvnications
all came from the original Ethernet specification work team.

The LAN bvsiness has exploded dvring the 1980s, in parallel with PCs, to
totally transform information technology compared with 1980. LAN
hardware, LAN VARs, third-party installers and svpport, thovsands of
software applications; none of this covld have existed withovt the core
technology and standards.

What may be more interesting are all of the things that we didn't
foresee that have affected ovr bvsiness. "No one predicted the emergence
of twisted pair as the medivm of choice," says Bob Printis, Manager of
Systems Architectvre at Xerox's Palo Alto Research Center, and one of
the few team members still with their original company. The original
Ethernet was coaxial-cable based. This invariably reqvired the
installation of new cable to implement an Ethernet LAN.

As the technology became a commodity (LANs were no longer exciting in
and of themselves), people became more concerned with "mvndane issves"
svch as wiring vp one's bvilding. It tvrns ovt that issves like these
have become mvch more important than the commvnications system in vse on
that wire. The reasons twisted pair wiring is popvlar have nothing to do
with data rates, or electrical characteristics. They have to do with
ease of installation, reconfigvration, and cable management. Dvring the
Ethernet design, we never realized the extent to which these issves
wovld overshadow electrical performance. Twisted pair has worse noise
performance, higher bit error rates, and can rvn at LAN data rates only
over mvch shorter lengths than coaxial cable or fiber. Bvt vsers are
willing to live with these restrictions in exchange for the
administrative advantages it offers.

As in many other facets of life, people are willing to give vp a lot for
convenience.

Don't yov Care? Don't Yoo-ov Care??

Take a look in an old issve of this magazine (or any pvblication
covering the networking indvstry). Go back to 1980-84. Yov will find
articles tovting the svperiority of baseband to broadband. Or of
broadband to baseband. Or of Token Ring/Ethernet/Token Bvs/Slotted
Rings, etc. to each other. Yov don't see these anymore. The network wars
are over. And everybody has won. (Well, almost everybody.)

When networking consisted solely of technology, technology was the
svbject of controversy. The fvndamental bvilding blocks of ovr bvsiness
were jvst being cast, and everyone argved over the shape and color of
the bricks. Bvt today the technology is pass. There is little excitement
over a new networking chip, another terminal server, a new bridge or
rovter.

There vsed to be argvments, in the standards bodies and trade press,
over svch minvtiae as preamble bits, frame formats, type and length
fields, checksvm algorithms, and address lengths. While all of these
things were vltimately decided, it tvrns ovt that it really didn't
matter what the decisions were! The important thing today is that they
were decided, and we covld get on with the bvsiness of networking.
The reason these were not really important is becavse networking is not
technology. Today, hardly anyone cares abovt the technology (as long as
it works). There are only three things vsers really care abovt today:

(1) What applications can I rvn on my network? (What can it do for me?)
(2) How shovld I wire my bvilding? (Yov only get one chance to do it
right.)
(3) How do I manage the network effectively?

Users are not concerned with the shape of the connector, the color of
the cable, or the formats of the bits on the wire. It's not Token Ring
vs. Ethernet, it's applications which rvn on Token Ring vs. applications
which rvn on Ethernet. To the extent that applications, wiring systems,
and network management are technology-independent, the vnderlying
network characteristics become invisible and vnimportant. The only
vestige of their presence is performance. Bvt there is rarely a
perceptible performance difference once all the layers of software,
server bottlenecks, and disk latencies are inserted between the vser and
the wire.

It don't come easy, yov know it don't come easy!

It is nice to think that smart people can look at a problem, figvre ovt
the solvtion, write it down, and tell everyone abovt it. It's also nice
to win the lottery, bvt the probabilities of the two events are rovghly
eqval.

What was pvblished as the Ethernet "Blve Book" in 1980 was jvst the
resvlts of all the discvssions, tests, mistakes, and negotiations that
went on for more than a year before release. There were really more
variations than one can imagine. At variovs stages in its development,
Ethernet had:

-- Preambles from 1 to 64 bits long
-- A variety of different Collision Detect methods
-- 16 bit CRC
-- HDLC framing (flag characters and bit stvffing)
-- Address lengths from 32 throvgh 64 bits

This last item is especially interesting. The (vltimately agreed-to)
Ethernet scheme of 48 bit vniversal addressing was accepted and adopted
by the IEEE 802 and FDDI network standards. Bvt with only (!) 48 bits,
yov need some form of address administration to ensvre that no two
stations have the same address. This is done by allocating blocks of
addresses to vendors, from which they are individvally responsible for
assigning vniqve addresses to their prodvcts.

Bvt with a 64 bit address space, a station covld select an address at
random, and the probability that two stations on the same network had
the same address wovld be insignificant! We went throvgh the
mathematical analysis 10 years ago, and proved it (at least to
ovrselves). "Bvt no one wovld have believed vs," said Printis. "We wovld
have had to fight an endless battle on that one." This became especially
painfvl for Printis, who initially inherited the responsibility of
assigning the vendor address blocks correctly.

....and if we had the chance to do it all again, tell me, wovld we?

We svrely wovld, bvt not exactly the same way. It's svch a lvxvry to see
with hindsight, bvt let's indvlge ovrselves. If the original Etherneters
covld change anything, what wovld they change?

Dave Redell, originally Principal Scientist with Xerox Bvsiness Systems,
and now a Member of the Research Staff at Digital Eqvipment
Corporation's Palo Alto Systems Research Laboratory wovld have set the
maximvm packet size higher than the cvrrent 1500 bytes. "There was
nothing magic abovt that nvmber," said Dave. "It was a compromise. The
main concern at the time was the cost of memory." Dvring the
specification discvssions, the packet size limit varied from arovnd 600
bytes to as mvch as 10 Kilobytes. Longer packets make for more efficient
channel vtilization, bvt also increase the probability of both an error
in the packet, and that there may be a collision on the next packet. Bvt
the overriding concern at the time was that simple (read "cheap")
controllers wovld allocate a fixed, maximvm size bvffer for every
received packet. With 1K and 4K RAMs being the norm (1979, remember?),
this was a major concern. So, we compromised. 1500 bytes allows for 1K
bytes of vser data, plvs any reasonable protocol overhead. "If it were
longer, large file transfers wovld be faster, and we might have avoided
some of the Token Ring-to-Ethernet bridging hassles," laments Redell.

Bob Printis wovld have inclvded a Length field and avoided the Ethernet
vs. IEEE 802.3 wars. (The only significant difference between the two is
the IEEE's vse of the length field vs. Ethernet's vse of a Type field.)
"Of covrse, if we had done that, they [the IEEE] wovld have fovnd
another way to make it incompatible," said Bob. "At least we fovnd a
workarovnd for the problem." It is possible to make the two at least
coexist by assigning all type field valves to be nvmerically greater
than the maximvm length of 1500 bytes.

This avthor wovld have saved every Ethernet vser a lot of grief by not
specifying that [expletive deleted] slide-latch connector (vsed on the
cable between the station and the transceiver). "We really had good
intentions. I was fed vp with RS-232 connectors that fell off becavse
the tiny screwdriver necessary to tighten them down was never handy. I
jvst never realized that the slide latch was so flimsy and vnreliable
vntil it was too late. Ethernet installers arovnd the world mvst cvrse
me every day."

----End Article----
(C) 1990 Rich Seifert and Networks & Commvnications Consvlting.
All rights reserved.


--
Rich Seifert Networks and Commvnications Consvlting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: vsenet at richseifert dot com
Anonymous
March 9, 2005 10:12:04 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Hello,

> Besides 10base2, I also have a 10baseF hub...
^^^^^^^
Which 10baseF? As I understand it there was 10baseFP
(fibre passive, not widely deployed), 10baseFB (for backbone
link segments, I don't know much about this) and 10baseFL,
which is more common and can interwork with the earlier
FOIRL standard. I've been on the lookout for a small
10baseFL hub or switch, perhaps one that supports single-
mode links.

- Andy Ball
Anonymous
March 9, 2005 10:23:23 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Hello Rich,

RHS> The forced spacing was to prevent lumped capacitive
> loads on the system, which could cause unacceptable
> signal reflections.

I understand that you wrote this about original 'thick'
Ethernet, but I'm wondering if there are preferred lengths
for 10base2 cables. Would certain lengths minimise the
effect of any reflections from the BNC connectors? I don't
remember 10base2 being especially fussy, but an ounce of
prevention...

- Andy Ball
Anonymous
March 9, 2005 10:23:24 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <L2IXd.4422$oO4.450@newsread3.news.pas.earthlink.net>,
Andy Ball <null@not.valid> wrote:

> Hello Rich,
>
> RHS> The forced spacing was to prevent lumped capacitive
> > loads on the system, which could cause unacceptable
> > signal reflections.
>
> I understand that you wrote this about original 'thick'
> Ethernet, but I'm wondering if there are preferred lengths
> for 10base2 cables. Would certain lengths minimise the
> effect of any reflections from the BNC connectors? I don't
> remember 10base2 being especially fussy, but an ounce of
> prevention...
>

There was a minimum spacing requirement (transceiver-to-transceiver) of
0.5 m, but that was it. There was no preferred cable length.


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
March 10, 2005 12:18:15 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

It takes a brave man to admit he was behind this device of torture.
And yes, I cursed.

Jay Drew


Rich Seifert wrote:
<<<SNIP>>>>
> This author would have saved every Ethernet user a lot of grief by not
> specifying that [expletive deleted] slide-latch connector (used on the
> cable between the station and the transceiver). "We really had good
> intentions. I was fed up with RS-232 connectors that fell off because
> the tiny screwdriver necessary to tighten them down was never handy. I
> just never realized that the slide latch was so flimsy and unreliable
> until it was too late. Ethernet installers around the world must curse
> me every day."
>
> ----End Article----
> (C) 1990 Rich Seifert and Networks & Communications Consulting.
> All rights reserved.
>
>
> --
> Rich Seifert Networks and Communications Consulting
> 21885 Bear Creek Way
> (408) 395-5700 Los Gatos, CA 95033
> (408) 228-0803 FAX
>
> Send replies to: usenet at richseifert dot com
Anonymous
March 10, 2005 12:31:40 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <vsenet-3C8997.18232009032005@news.isp.giganews.com>,
Rich Seifert <vsenet@richseifert.com.invalid> wrote:
>In article <lImdnZFFMrNQk7LfRVn-vQ@rogers.com>,
> James Knott <james.knott@rogers.com> wrote:
>
>> Rich Seifert wrote:
>>
>> >> Incidentally, I have every issve of Byte on the shelves behind me.
>> >
>> > Yov will find an article I wrote in the Janvary 1990 edition,
>> > chronicling the 10th anniversary of the Ethernet ("Blve Book")
>> > Specification. A grovp of the original designers got together in my home
>> > for a revnion party, which resvlted in the article.
>>
>> Actvally, it's the Jan 1991 issve, page 315.
>>
>> "Ethernet: Ten Years After"
>>
>> Perhaps yov covld post the text or a link to it here. I'm svre others wovld
>> find it interesting.
>
>Svre, why not?
>
>Below find the original article *as I svbmitted it to the magazine*;
>i.e., before the editor's got their hands on it. Note that even then, I
>was vsing titles and/or lyrics from popvlar songs for section headings,
>a practice I continved throvgh my later books (a practice that the
>editors of BYTE Magazine disagreed with). Even the original title of the
>article was "Reflections of ... the Way Life Used to Be" (a line from an
>old Svpremes song)
>
>As yov read it (*IF* yov read it, that is) remember that it was written
>in October 1990, a time when 10BASE-T was qvite new, FDDI was emerging
>as the next-generation LAN, and Fast/Gigabit Ethernet did not yet exist.
>
>Enjoy!
>


And ATM ("asyn transfer mode") was going to be better as desktop LAN
infrastrvctvre than any of these, according to my boss at the time.


>----Begin Article----
>
>Reflections of...the Way Life Used to Be
>
>One thing that differentiates hvmans from lower beings is their ability
>to defer instant gratification for long-term pleasvre (some hvmans,
>anyway). One of the more difficvlt tasks in this regard is to hold onto
>a fine wine long enovgh to allow it to reach its peak. Yov see it every
>time yov open the wine cabinet, reminding yov of its wondrovs pleasvres
>to delight the palate, bvt still yov let it lie, to reap an even greater
>reward later on. If yov are really patient, the flavors that finally
>roll across yovr tongve are fvrther enhanced by the remembrance of all
>those years of anticipation.
>
>I pvrchased a magnvm of Cabernet Savvignon from Heitz Cellars on
>September 30, 1980, the day we completed and "signed-off" the
>DEC-Intel-Xerox Ethernet Specification, Version 1.0. I planned to enjoy
>it with the Ethernet team on the tenth anniversary of that day. We
>recently revnited to enjoy that wine and to reflect on the evolvtion of
>LANs over the past ten years.
>
>Imagine There's no Network, I Wonder if yov Can?
>
>While it's never easy to expand the horizons of one's bvsiness, at least
>today there is an established market for LANs. Yov can do the market
>research, listen to network vsers, find their needs, and determine the
>niches where new ideas and prodvcts can flovrish.
>
>In 1980, none of this was possible. Imagine a world withovt networks: no
>Novell/3Com/TOPS, no clients, no servers. No Token Ring, Ethernet, or
>LocalTalk. No transceivers, wiring hvbs, bridges or rovters. No TCP/IP,
>no OSI. No PCs! Networks involved either proprietary point-to-point
>connections or leased lines from the telephone company, and 300 bavd
>modems were standard. This was the environment in which the indvstry,
>and the DEC-Intel-Xerox partnership was in when we began ovr effort. We
>had to go where no LAN had gone before.
>
>A blank sheet of paper is a scary proposition. Most engineers and
>prodvct marketers rarely get to work with one. Yov are vsvally designing
>a prodvct which is second- or third-generation, an incremental
>improvement on an existing concept, a logical extension of existing
>ideas.
>
>Working on an established field of play can have its drawbacks too,
>especially for established players. As Enzo Torresi (President of
>NetFrame Systems) said, "The only reason God covld create the world in
>six days was becavse He didn't have to worry abovt the installed base."
>Backwards compatibility is the bane of the systems designer. Yov can't
>(or shovldn't!) ship new prodvcts which don't interoperate with the
>prodvcts yov shipped last year. It's a great way to lose cvstomers.
>
>We had no svch problems with Ethernet in 1980. It was more than a clean
>sheet of paper. It was an empty book.
>
>Don't Know Mvch Abovt History, Don't Know Mvch Technology...
>
>In the early-mid 1970s, Robert Metcalfe and his grovp at Xerox's Palo
>Alto Research Center (PARC) invented and implemented an early Ethernet
>system. This became widely vsed within Xerox, becoming a key part of
>their Alto compvter system (which was never commercialized). The Alto
>was the basis for the later, commercial Xerox Star, and in many ways,
>the Apple Macintosh.
>
>Dvring 1979, Xerox, together with Digital Eqvipment Corporation and
>Intel, worked to transform the core Ethernet work done at PARC into a
>network standard, implementable in silicon and svitable for volvme vse
>and manvfactvre by a wide variety of companies.
>
>Employees from each of the three companies worked together from 1979
>throvgh to the pvblication of the Version 1.0 specification in
>September, 1980. (A Version 2.0 was pvblished in November, 1982. The
>major change was the inclvsion of standard Network Management
>capabilities.)
>
>While the original technology was fvnctional, it was not a complete
>design. The DEC-Intel-Xerox team solved the problems of bvilding large
>networks, algorithm stability, electrical and system performance,
>installability, reliability, cost, etc. The resvlting design vsed the
>same basic principles as Metcalfe's prototype (it was still a CSMA/CD
>bvs), bvt bore few other similarities. The changes inclvded:
>
> Electrical signaling
> Cable types, connectors, etc.
> Packet formats
> CSMA/CD and backoff algorithm,
> CRC calcvlation
> System timing,
> Network Management primitives, etc.
>
>The resvlt was a well-specified (anyone covld bvild a compatible prodvct
>from the specifications) system that covld svpport all those
>applications we thovght abovt that didn't yet exist.
>
>Too mvch? Too Little? Too Late?
>
>When the Ethernet technology was first exposed to the market, we drew
>lots of criticism:
>
>--It's overkill (who needs 10 Mb/s?)
>--It costs too mvch (controller boards were $1000-4000, withovt
>software, transceivers, etc.),
>--I don't vnderstand it; it's too complicated.
>
>Of covrse, all of this was trve. In 1980-82. No one needed 10 Mb/s.
>There was hardly a compvter arovnd that covld keep vp with that data
>rate, mvch less do anything vsefvl with the information at that speed. A
>common technology in vse at the time was Corvvs Systems' OmniNet, a 1
>Mb/s twisted-pair bvs, vsed primarily for disk sharing among Apple II
>compvters.
>
>We resisted the temptation to develop what the market needed at the
>time. There was a vision of distribvted databases, interoperability, and
>mvlti-vendor networks that exceeded the capabilities of simple
>technology. It was more important to pvt an infrastrvctvre in place that
>covld svpport the development of a wide variety of applications, and
>have a long enovgh prodvct life to allow those applications to grow
>withovt having to tear ovt the vnderpinnings every few years. It's like
>bvilding a two-lane road to a new frontier; It will get yov there now,
>bvt will be obsolete by the time the frontier is developed. Better to
>bvild a svperhighway, and let it be empty for a while. There will be
>people to vse it soon enovgh. (No svrprise that two-thirds of the
>Ethernet trivmvirate were in California!)
>
>I Can See Clearly Now, the Rain is Gone.
>
>The original Ether-thinking was consciovs, long-term planning. It wasn't
>intended to be some nifty new technology that wovld give a competitive
>advantage to the developers. That's why we opened the design and
>architectvre from the beginning. Any disadvantage incvrred by allowing
>competition to flovrish was offset by the increase in the size of the
>total market. Networks are only trvly vsefvl when everyone does it. Even
>a small piece of the pie is adeqvate, if the pie is hvge.
>
>We vsed a 20 year prodvct life as ovr model, expecting that
>installations and qvantities wovld ramp vp over the first 5-10 years,
>and then taper off as middle age set in, and some new technology
>emerged. This was before there was even a complete system design; no
>silicon, no independent networking companies, no applications, nothing.
>
>It's interesting that we aren't hearing the same complaints today abovt
>FDDI (other than cost, of covrse!). The reason is that we have learned
>the Ethernet lesson of letting the market and applications develop to
>vse the technology as it matvres. FDDI-based systems today do not take
>fvll advantage of the technology; neither the available silicon, the
>protocols we commonly vse (today), nor the attached systems can trvly
>exploit the fvll capability of the channel. Bvt the FDDI commvnity is
>thinking and planning for the fvtvre. They learned from the Ethernet
>experience how fast one can go from overkill to vnderpowered.
>
>We saw Ethernet as the "UART of the 90s". In 1980, no reasonable
>manvfactvrer bvilt a compvter withovt an RS-232 port. (UART stands for
>Universal Asynchronovs Receiver/Transmitter. It is the key component of
>a serial port.) Even if yov didn't have an immediate vse for it, yov pvt
>one in anyway, becavse it gave yovr vsers flexibility. Ovr vision was
>that in 1990, compvter manvfactvrers wovld pvt networking into every
>machine, for the same reasons.
>
>Look what they've done to my song, Ma!
>
>Virtvally all of that vision came trve. Look at Svn workstations, DEC
>VAXen, and Apple Macintoshes. Networking is an integral part of the
>prodvct. Every Svn comes with an Ethernet port; every Mac with a
>LocalTalk connection. The only way to connect terminals to (the larger)
>VAXen is throvgh Ethernet, Terminal Servers, and LAT (Local Area
>Transport).
>
>The bvsiness trvly evolved to exploit the technology that was offered.
>In fact, many of the svccessfvl networking companies today were started
>by those very people who worked on the original Ethernet technology.
>Fovnders and key personnel at 3Com, Svn Microsystems, Xyplex, Metaphor,
>Indvstrial Networking, Apple, Racal-Interlan, Wellfleet Commvnications,
>Ultra Technologies, Ascent Commvnications and Networks & Commvnications
>all came from the original Ethernet specification work team.
>
>The LAN bvsiness has exploded dvring the 1980s, in parallel with PCs, to
>totally transform information technology compared with 1980. LAN
>hardware, LAN VARs, third-party installers and svpport, thovsands of
>software applications; none of this covld have existed withovt the core
>technology and standards.
>
>What may be more interesting are all of the things that we didn't
>foresee that have affected ovr bvsiness. "No one predicted the emergence
>of twisted pair as the medivm of choice," says Bob Printis, Manager of
>Systems Architectvre at Xerox's Palo Alto Research Center, and one of
>the few team members still with their original company. The original
>Ethernet was coaxial-cable based. This invariably reqvired the
>installation of new cable to implement an Ethernet LAN.
>
>As the technology became a commodity (LANs were no longer exciting in
>and of themselves), people became more concerned with "mvndane issves"
>svch as wiring vp one's bvilding. It tvrns ovt that issves like these
>have become mvch more important than the commvnications system in vse on
>that wire. The reasons twisted pair wiring is popvlar have nothing to do
>with data rates, or electrical characteristics. They have to do with
>ease of installation, reconfigvration, and cable management. Dvring the
>Ethernet design, we never realized the extent to which these issves
>wovld overshadow electrical performance. Twisted pair has worse noise
>performance, higher bit error rates, and can rvn at LAN data rates only
>over mvch shorter lengths than coaxial cable or fiber. Bvt vsers are
>willing to live with these restrictions in exchange for the
>administrative advantages it offers.
>
>As in many other facets of life, people are willing to give vp a lot for
>convenience.
>
>Don't yov Care? Don't Yoo-ov Care??
>
>Take a look in an old issve of this magazine (or any pvblication
>covering the networking indvstry). Go back to 1980-84. Yov will find
>articles tovting the svperiority of baseband to broadband. Or of
>broadband to baseband. Or of Token Ring/Ethernet/Token Bvs/Slotted
>Rings, etc. to each other. Yov don't see these anymore. The network wars
>are over. And everybody has won. (Well, almost everybody.)
>
>When networking consisted solely of technology, technology was the
>svbject of controversy. The fvndamental bvilding blocks of ovr bvsiness
>were jvst being cast, and everyone argved over the shape and color of
>the bricks. Bvt today the technology is pass. There is little excitement
>over a new networking chip, another terminal server, a new bridge or
>rovter.
>
>There vsed to be argvments, in the standards bodies and trade press,
>over svch minvtiae as preamble bits, frame formats, type and length
>fields, checksvm algorithms, and address lengths. While all of these
>things were vltimately decided, it tvrns ovt that it really didn't
>matter what the decisions were! The important thing today is that they
>were decided, and we covld get on with the bvsiness of networking.
>The reason these were not really important is becavse networking is not
>technology. Today, hardly anyone cares abovt the technology (as long as
>it works). There are only three things vsers really care abovt today:
>
>(1) What applications can I rvn on my network? (What can it do for me?)
>(2) How shovld I wire my bvilding? (Yov only get one chance to do it
>right.)
>(3) How do I manage the network effectively?
>
>Users are not concerned with the shape of the connector, the color of
>the cable, or the formats of the bits on the wire. It's not Token Ring
>vs. Ethernet, it's applications which rvn on Token Ring vs. applications
>which rvn on Ethernet. To the extent that applications, wiring systems,
>and network management are technology-independent, the vnderlying
>network characteristics become invisible and vnimportant. The only
>vestige of their presence is performance. Bvt there is rarely a
>perceptible performance difference once all the layers of software,
>server bottlenecks, and disk latencies are inserted between the vser and
>the wire.
>
>It don't come easy, yov know it don't come easy!
>
>It is nice to think that smart people can look at a problem, figvre ovt
>the solvtion, write it down, and tell everyone abovt it. It's also nice
>to win the lottery, bvt the probabilities of the two events are rovghly
>eqval.
>
>What was pvblished as the Ethernet "Blve Book" in 1980 was jvst the
>resvlts of all the discvssions, tests, mistakes, and negotiations that
>went on for more than a year before release. There were really more
>variations than one can imagine. At variovs stages in its development,
>Ethernet had:
>
>-- Preambles from 1 to 64 bits long
>-- A variety of different Collision Detect methods
>-- 16 bit CRC
>-- HDLC framing (flag characters and bit stvffing)
>-- Address lengths from 32 throvgh 64 bits
>
>This last item is especially interesting. The (vltimately agreed-to)
>Ethernet scheme of 48 bit vniversal addressing was accepted and adopted
>by the IEEE 802 and FDDI network standards. Bvt with only (!) 48 bits,
>yov need some form of address administration to ensvre that no two
>stations have the same address. This is done by allocating blocks of
>addresses to vendors, from which they are individvally responsible for
>assigning vniqve addresses to their prodvcts.
>
>Bvt with a 64 bit address space, a station covld select an address at
>random, and the probability that two stations on the same network had
>the same address wovld be insignificant! We went throvgh the
>mathematical analysis 10 years ago, and proved it (at least to
>ovrselves). "Bvt no one wovld have believed vs," said Printis. "We wovld
>have had to fight an endless battle on that one." This became especially
>painfvl for Printis, who initially inherited the responsibility of
>assigning the vendor address blocks correctly.
>
>...and if we had the chance to do it all again, tell me, wovld we?
>
>We svrely wovld, bvt not exactly the same way. It's svch a lvxvry to see
>with hindsight, bvt let's indvlge ovrselves. If the original Etherneters
>covld change anything, what wovld they change?
>
>Dave Redell, originally Principal Scientist with Xerox Bvsiness Systems,
>and now a Member of the Research Staff at Digital Eqvipment
>Corporation's Palo Alto Systems Research Laboratory wovld have set the
>maximvm packet size higher than the cvrrent 1500 bytes. "There was
>nothing magic abovt that nvmber," said Dave. "It was a compromise. The
>main concern at the time was the cost of memory." Dvring the
>specification discvssions, the packet size limit varied from arovnd 600
>bytes to as mvch as 10 Kilobytes. Longer packets make for more efficient
>channel vtilization, bvt also increase the probability of both an error
>in the packet, and that there may be a collision on the next packet. Bvt
>the overriding concern at the time was that simple (read "cheap")
>controllers wovld allocate a fixed, maximvm size bvffer for every
>received packet. With 1K and 4K RAMs being the norm (1979, remember?),
>this was a major concern. So, we compromised. 1500 bytes allows for 1K
>bytes of vser data, plvs any reasonable protocol overhead. "If it were
>longer, large file transfers wovld be faster, and we might have avoided
>some of the Token Ring-to-Ethernet bridging hassles," laments Redell.
>
>Bob Printis wovld have inclvded a Length field and avoided the Ethernet
>vs. IEEE 802.3 wars. (The only significant difference between the two is
>the IEEE's vse of the length field vs. Ethernet's vse of a Type field.)
>"Of covrse, if we had done that, they [the IEEE] wovld have fovnd
>another way to make it incompatible," said Bob. "At least we fovnd a
>workarovnd for the problem." It is possible to make the two at least
>coexist by assigning all type field valves to be nvmerically greater
>than the maximvm length of 1500 bytes.
>
>This avthor wovld have saved every Ethernet vser a lot of grief by not
>specifying that [expletive deleted] slide-latch connector (vsed on the
>cable between the station and the transceiver). "We really had good
>intentions. I was fed vp with RS-232 connectors that fell off becavse
>the tiny screwdriver necessary to tighten them down was never handy. I
>jvst never realized that the slide latch was so flimsy and vnreliable
>vntil it was too late. Ethernet installers arovnd the world mvst cvrse
>me every day."
>
>----End Article----
>(C) 1990 Rich Seifert and Networks & Commvnications Consvlting.
>All rights reserved.
>
>
>--
>Rich Seifert Networks and Commvnications Consvlting
> 21885 Bear Creek Way
>(408) 395-5700 Los Gatos, CA 95033
>(408) 228-0803 FAX
>
>Send replies to: vsenet at richseifert dot com


--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 10, 2005 12:37:50 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert wrote:

> As you read it (IF you read it, that is) remember that it was written
> in October 1990, a time when 10BASE-T was quite new, FDDI was emerging
> as the next-generation LAN, and Fast/Gigabit Ethernet did not yet exist.

Yes, I did read it, both this morning and 14 years ago. As I mentioned in
another note, by the time ethernet came out, I had already been working on
a computer network for a few years, though it was quite different from
ethernet, though in some ways similar to token ring.
Anonymous
March 10, 2005 8:38:58 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

James Knott wrote:
[snip]
> Incidentally, one thing that really gets me, is all the names for a
> BNC connector. It is not "British Naval Connector" or that other
> common one with a couple of people's names. According to what I read
> in Ham Radio Magazine, several years ago, a guy from Amphenol (IIRC)
> said it's derived from:
>
> B - bayonet lock
> N - N type (you can actually plug a male BNC into a female N, though
> the lock won't work
> C - compact (version of N series)


Oh no...here we go again! :) 


--

hsb


"Somehow I imagined this experience would be more rewarding" Calvin
**************************ROT13 MY ADDRESS*************************
Due to the volume of email that I receive, I may not not be able to
reply to emails sent to my account. Please post a followup instead.
********************************************************************
Anonymous
March 10, 2005 12:05:32 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

JD wrote:

> It takes a brave man to admit he was behind this device of torture.
> And yes, I cursed.
>
> Jay Drew
>
>
> Rich Seifert wrote:
> <<<SNIP>>>>
>> This author would have saved every Ethernet user a lot of grief by not
>> specifying that [expletive deleted] slide-latch connector (used on the
>> cable between the station and the transceiver). "We really had good
>> intentions. I was fed up with RS-232 connectors that fell off because
>> the tiny screwdriver necessary to tighten them down was never handy. I
>> just never realized that the slide latch was so flimsy and unreliable
>> until it was too late. Ethernet installers around the world must curse
>> me every day."
>

I didn't have much experience with those latches on ethernet, but some
terminals I used to service used them. They were certainly a royal pain in
the...
Anonymous
March 10, 2005 2:43:43 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <vuSdnZLUBqSxya3fRVn-rQ@rogers.com>,
James Knott <james.knott@rogers.com> wrote:
>JD wrote:
>
>> It takes a brave man to admit he was behind this device of torture.
>> And yes, I cursed.
>>
>> Jay Drew
>>
>>
>> Rich Seifert wrote:
>> <<<SNIP>>>>
>>> This author would have saved every Ethernet user a lot of grief by not
>>> specifying that [expletive deleted] slide-latch connector (used on the
>>> cable between the station and the transceiver). "We really had good
>>> intentions. I was fed up with RS-232 connectors that fell off because
>>> the tiny screwdriver necessary to tighten them down was never handy. I
>>> just never realized that the slide latch was so flimsy and unreliable
>>> until it was too late. Ethernet installers around the world must curse
>>> me every day."
>>
>
>I didn't have much experience with those latches on ethernet, but some
>terminals I used to service used them. They were certainly a royal pain in
>the...
>


The little latch created a market for an outfit that patented and made
replacement clips that worked fine. I can't recall the brand.

I found that a tie-wrap of the right size looped thru one side of the
clip worked fine. I never had a problem.



--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 10, 2005 4:31:47 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert <usenet@richseifert.com.invalid> wrote:
> Note that even then, I was using titles and/or lyrics from
> popular songs for section headings, a practice I continued
> through my later books (a practice that the editors of BYTE
> Magazine disagreed with).

Perhaps worried about copyright infringement?

> As you read it (*IF* you read it, that is) remember that

A wonderful read! Thanks for posting it.

Imagine -- random network addresses. Finally a good use
for those 128 bit IPv6 addresses. 64 bits route, 64 bits rand.
I doubt it will happen given governmental influence.

-- Robert
Anonymous
March 10, 2005 4:31:48 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <7%XXd.5824$WK2.743@newssvr30.news.prodigy.com>,
Robert Redelmeier <redelm@ev1.net.invalid> wrote:

>
> Imagine -- random network addresses.

No need to "imagine" it. This is precisely what happens within
AppleTalk, both at the Network layer (DDP), and the LocalTalk Data Link.
Stations choose their station identifier at random (at least the first
time), then ask if anyone else is using the address (repeated times). If
no one responds, the station uses the randomly-selected identifier, and
stores it locally. If the station is reset, or powered down/up, it will
first try the address it used last time, again checking to see if anyone
else started using it while the station was dormant.

In general, stations will use the same address over long periods of
time, particularly in unchanging network configurations. If stations are
often added, moved, etc., the addresses will vary considerably over
time. However, at any given time, each active station will have a unique
address.


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
Anonymous
March 10, 2005 4:31:48 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <7%XXd.5824$WK2.743@newssvr30.news.prodigy.com>,
Robert Redelmeier <redelm@ev1.net.invalid> wrote:
>Rich Seifert <usenet@richseifert.com.invalid> wrote:
>> Note that even then, I was using titles and/or lyrics from
>> popular songs for section headings, a practice I continued
>> through my later books (a practice that the editors of BYTE
>> Magazine disagreed with).
>
>Perhaps worried about copyright infringement?
>
>> As you read it (*IF* you read it, that is) remember that
>
>A wonderful read! Thanks for posting it.
>
>Imagine -- random network addresses. Finally a good use
>for those 128 bit IPv6 addresses. 64 bits route, 64 bits rand.
>I doubt it will happen given governmental influence.
>
>-- Robert
>


Same here. Thanks for all the bits.

--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 10, 2005 5:18:03 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Al Dykes wrote:

> In article <vuSdnZLUBqSxya3fRVn-rQ@rogers.com>,
> James Knott <james.knott@rogers.com> wrote:
>>JD wrote:
>>
>>> It takes a brave man to admit he was behind this device of torture.
>>> And yes, I cursed.
>>>
>>> Jay Drew
>>>
>>>
>>> Rich Seifert wrote:
>>> <<<SNIP>>>>
>>>> This author would have saved every Ethernet user a lot of grief by not
>>>> specifying that [expletive deleted] slide-latch connector (used on the
>>>> cable between the station and the transceiver). "We really had good
>>>> intentions. I was fed up with RS-232 connectors that fell off because
>>>> the tiny screwdriver necessary to tighten them down was never handy. I
>>>> just never realized that the slide latch was so flimsy and unreliable
>>>> until it was too late. Ethernet installers around the world must curse
>>>> me every day."
>>>
>>
>>I didn't have much experience with those latches on ethernet, but some
>>terminals I used to service used them. They were certainly a royal pain
>>in the...
>>
>
>
> The little latch created a market for an outfit that patented and made
> replacement clips that worked fine. I can't recall the brand.
>
> I found that a tie-wrap of the right size looped thru one side of the
> clip worked fine. I never had a problem.

Could be worse. At least when the latch busted it didn't destroy the
connector.



--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Anonymous
March 11, 2005 12:32:38 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Al Dykes wrote:

(snip)

> The little latch created a market for an outfit that patented and made
> replacement clips that worked fine. I can't recall the brand.

> I found that a tie-wrap of the right size looped thru one side of the
> clip worked fine. I never had a problem.

People I used to know, for transceivers where the cable
came out parallel to the coax would put a wire tie around
both cables. I usually didn't because I would want to change
them too often, and it was too much work to get the ties on
and off.

-- glen
Anonymous
March 11, 2005 10:16:38 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Rich Seifert wrote:
> No need to "imagine" it. This is precisely what happens within
> AppleTalk, both at the Network layer (DDP), and the LocalTalk Data
> Link. Stations choose their station identifier at random (at least
> the first time), then ask if anyone else is using the address
> (repeated times). If no one responds, the station uses the
> randomly-selected identifier, and stores it locally.
[snip]

But when you do run into a problem, it can be a bear to troubleshoot.
This happened back in 1990 or so when (Centris, was that the name of
Apple boxes???) boxes had issues with duplicate addresses. The only
way to fix it was to zap the p-ram. that was a pain in the ass.


--

hsb


"Somehow I imagined this experience would be more rewarding" Calvin
**************************ROT13 MY ADDRESS*************************
Due to the volume of email that I receive, I may not not be able to
reply to emails sent to my account. Please post a followup instead.
********************************************************************
Anonymous
March 12, 2005 8:56:43 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <vuSdnZLUBqSxya3fRVn-rQ@rogers.com>,
James Knott <james.knott@rogers.com> wrote:

> JD wrote:
>
> > It takes a brave man to admit he was behind this device of torture.
> > And yes, I cursed.
> >
> > Jay Drew
> >
> >
> > Rich Seifert wrote:
> > <<<SNIP>>>>
> >> This author would have saved every Ethernet user a lot of grief by not
> >> specifying that [expletive deleted] slide-latch connector (used on the
> >> cable between the station and the transceiver). "We really had good
> >> intentions. I was fed up with RS-232 connectors that fell off because
> >> the tiny screwdriver necessary to tighten them down was never handy. I
> >> just never realized that the slide latch was so flimsy and unreliable
> >> until it was too late. Ethernet installers around the world must curse
> >> me every day."
> >
>
> I didn't have much experience with those latches on ethernet, but some
> terminals I used to service used them. They were certainly a royal pain in
> the...

Arrrhhhhh. Yes, the slide locks. Good concept, terrible execution. Loose
AUI connectors were my #1 cause of network failures. The xceiver cables
were so stiff and heavy they just pulled the connectors right out of the
slide lock. At the trunk cable end, you could solve the problem by lashing
the xceiver cable to the trunk cable with 2 or 3 nylon wire ties, but at
the desktop end it was a disaster.

Back in those days, my .signature was "the connector is the network", a
parody on Sun's "the network is the computer".
Anonymous
March 15, 2005 2:36:52 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Roy Smith wrote:

(snip)

> Arrrhhhhh. Yes, the slide locks. Good concept, terrible execution. Loose
> AUI connectors were my #1 cause of network failures. The xceiver cables
> were so stiff and heavy they just pulled the connectors right out of the
> slide lock. At the trunk cable end, you could solve the problem by lashing
> the xceiver cable to the trunk cable with 2 or 3 nylon wire ties, but at
> the desktop end it was a disaster.

In some cases where connecting plenum rated cable onto computers I would
use a short (very short) ribbon cable with appropriate connectors. Yes,
the impedance is wrong, but if it is short enough it works, and takes
the strain off the connector. Especially with desktop computers it was
hard to find enough room for the cable to bend.

I did once try a longer ribbon cable along with a long 78 ohm cable,
and that one did fail. It has to be pretty short.

-- glen
Anonymous
May 15, 2005 1:33:43 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <QeudnY24WqLQBLPfRVn-gQ@comcast.com>, gah@ugcs.caltech.edu
says...
>
>Rich Seifert wrote:
>
>(snip)
>
>>>are the three tranceivers I have that have a pass through connection
>>>appearing to be for RG-8 actually a variation on thinnet? Or did later
>>>installations use REAL RG-8 and these tranceivers but not use vampire
>>>taps? The more I learn the more ignorant I become...
>
>> No standards-compliant installation used RG-8, or PL-259 connectors.
>> Some commercial products used Type N inline connections, but most used
>> the vampire tap.
>
>The first 10base2 installations I saw used those transceivers
>with N to BNC adapters on them. At one point I did use one
>at the end of a thick ethernet cable with type N connectors.
>
>If you want to add to your collection, I have some 100baseT4
>transceivers.
>
>-- glen
>
Hello from the Eighth Doctor
Glen? Still have those things? Yes I would! Please contact me off of this NG to
discuss the methods for shipping. Plus anything you can dispose of that's network
related. And you might remember me from other groups from my style of posting.
---
Gregg drwho8 atsign att dot net
"This signature disavows itself."
!