The baud rate for the standard 10-Mbps 802.3 LAN
Cristian HERLING
Hello, is there anybody who can tell the baud rate for a 10Mbps 802.3
LAN or give an URL where I can find related info?
I looked all over the web and couldn't find it
Thnaks a lot!!
--
Am un singur viciu,
Deliciu personal,
Berea de la doaga,
In cana de metal.
Tony Phillips
Depends on your definition of Baud.
The bps rating is, of course, 10 million bits per second.
The BAUD rate (the number of changes of discrete signals per second)
can vary depending on what is being transmitted.
It can be as little as 10 Megabaud, or as high as 20 Megabaud.
It's at its minima when the bits are constant streams of 1's & 0's
It's at its maxima when its alternating 1's & 0's.
Cristian HERLING wrote in message <794ic0$6...@sifon.cc.mcgill.ca>...
Someone
Is 10Mbps, 10,000,000 bits pers second or 1024*1024 bits per second
(1048576bps)? Seems to me there was a difference between Meg and MB when
talking about RAM, I suspect it doesn't apply when talking about LAN speeds.
Also is 1Kbps, 1024bps or 1000bps?
Tony Phillips wrote in message <79544s$k1k$1...@tilde.csc.ti.com>...
Kevin Oberman
> Another question here.
>
> Is 10Mbps, 10,000,000 bits pers second or 1024*1024 bits per second
> (1048576bps)? Seems to me there was a difference between Meg and MB when
> talking about RAM, I suspect it doesn't apply when talking about LAN speeds.
>
> Also is 1Kbps, 1024bps or 1000bps?
In communications, 1 K means 100. The use of 1024 as 1K in computers
derives from the fact that resources are normally handled in powers of
2 (512, 1024, 2048, 4096,...) and 1024 is pretty close to 1000.
Since data communications has no such characteristics, 10 Mbps is
10,000,000 bits/second.
--
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: obe...@es.net Phone: +1 510 486-8634
Bob Retelle
wrote:
>
>Hello, is there anybody who can tell the baud rate for a 10Mbps 802.3
>LAN or give an URL where I can find related info?
>I looked all over the web and couldn't find it
>
>Thnaks a lot!!
>--
>Am un singur viciu,
>Deliciu personal,
>Berea de la doaga,
>In cana de metal.
The term "baud" has no meaning or application in 802.3 ethernet.
Data is transferred at a nominal rate of 10 million bits per second.
"Baud" essentially does not apply to serial communications over 9600
bits per second at any rate.
BobR@ADP
Dave Beal
Bob Retelle wrote:
> On 1 Feb 1999 15:48:16 GMT, cris...@cs.mcgill.ca (Cristian HERLING)
> wrote:
>
> >
> >Hello, is there anybody who can tell the baud rate for a 10Mbps 802.3
> >LAN or give an URL where I can find related info?
> >I looked all over the web and couldn't find it
> >
>
> The term "baud" has no meaning or application in 802.3 ethernet.
>
> Data is transferred at a nominal rate of 10 million bits per second.
>
> "Baud" essentially does not apply to serial communications over 9600
> bits per second at any rate.
We're arguing over semantics here, I suppose, but I'd have to disagree
with you, Bob. Just because the term "baud" originated with serial async
communication doesn't mean that it's limited to that domain; the concept
applies to any form of digital communication.
Baud refers to the rate at which the data-bearing signal changes.
Depending on the encoding method, this could be a
change in amplitude, frequency, voltage, phase, etc.
In the case of ethernet, the encoding is Manchester, which means
that the signal always changes in the middle of a bit time, and
sometimes changes between bit times. Therefore, the baud
rate for ethernet varies from 10 to 20 Mbaud.
Manfred Kwiatkowski
>
> "Baud" essentially does not apply to serial communications over 9600
> bits per second at any rate.
said my textbook from mid '70s :-)
--
Manfred Kwiatkowski kwiat...@zrz.tu-berlin.de
Chris Ruffin
Bob Retelle wrote in message <36b831ec....@ns1.autonet.net>...
<snip>
>"Baud" essentially does not apply to serial communications over 9600
>bits per second at any rate.
Sure it does. It may not be the de facto standard for talking about
this
sort of thing, but the concept of the "baud" is a general concept that
doesn't imply any specific communication system.
Baud in general, is the number of transitions per second of the
signaling
on the communications medium. Bits per second (BPS) is a factor related
to
the baud rate by the number of bits sent per transition (per second).
If
you have eight different transition levels in a communication system,
and
you change transitions once per second, then you have one BAUD but three
BPS.
Although I don't know the details, if Ethernet is a two level signaling
system, then baud = BPS. Actually, I'd like to know. Is it?
Ah, sorry, I just felt like being picky today.
Chris
Rich Seifert
>
> The term "baud" has no meaning or application in 802.3 ethernet.
>
> bits per second at any rate.
>
This is simply not true. The baud rate is the rate of signal change on the
medium (usually expressed as a worst-case value). Since 10 Mb/s Ethernet
uses one transition (per bit) for the clock, and a second transition for
data (in the worst-case), it has a baud rate of 20 Mbaud.
Fast Ethernet is somewhat different. The use of 4B/5B encoding results in 5
code-bits for every 4 data bits. Then you have to look at the line
signaling.
In the case of 100BASE-FX, we use NRZI, which will result in a transition
for every code bit, in the worst-case (a string of all ones, as is used for
IDLE signaling). Thus, the baud rate is 125 Mbaud.
For 100BASE-TX, we use MLT-3 encoding, which has a maximum of one
transition for every two code-bits. Thus, the baud rate is 62.5 Mbaud (and
the maximum fundamental frequency is 31.25 MHz).
Here's the definition from the IEEE Dictionary:
"A unit of signaling speed, expressed as the number of times per second the
signal can change the electrical state of the transmission line or other
medium. Note: Depending on the encoding strategies, a signal event may
represent a single bit, more, or less, than one bit."
--
Rich Seifert Networks and Communications Consulting
sei...@netcom.com 21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 395-1966 FAX
"... specialists in Local Area Networks and Data Communications systems"
Rich Seifert
<sp...@sucks.com> wrote:
>
> Is 10Mbps, 10,000,000 bits pers second or 1024*1024 bits per second
> (1048576bps)? Seems to me there was a difference between Meg and MB when
> talking about RAM, I suspect it doesn't apply when talking about LAN speeds.
>
Good observation. In memory designs, sizes naturally fall on "power of 2"
boundaries, due to the addressing. (Why waste address space?)
In communications, there is no natural "power of 2" boundary. Bit and baud
rates are in decimal values. A "meg" of RAM is 1024^2; a megabit-per-second
is 1,000,000 bits/second. (Similarly for 10 Mb/s, 100 Mb/s, etc.)
> Also is 1Kbps, 1024bps or 1000bps?
It's 1000 bits/sec. Same for 56 kb/s and 64 kb/s (which is 64000, not 65536).