Matt,
You're 101% correct. We will be developing an amendment for EPoC and
not a new spec, so some of the discussion, while technically correct,
might be moot
Marek
*From:* Matthew Schmitt [mailto:m.schmitt@xxxxxxxxxxxxx]
*Sent:* Tuesday, August 21, 2012 03:12
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Someone will correct me if I'm wrong, but if memory serves we won't be
writing an EPoC spec; rather, we'll be generating amendments to the
Ethernet spec. If so, rather than having to rewrite how a term is used
throughout the entire existing spec (even if we could get away with
it), might it be a good idea to use existing terms as they're already
used?
Matt
On Aug 20, 2012, at 7:17 PM, "Jain, Rajeev" <rajeevj@xxxxxxxxxxxx
<mailto:rajeevj@xxxxxxxxxxxx>> wrote:
Thanks Hal.
I dare say the "Bandwidth" for bit rate is a marketing term that
has crept in over the years -- salesmen in Best Buy can more
easily convince the consumers they need "more bandwidth" to sell a
higher speed router than "higher bit rate". "Bandwidth" has a feel
good consumerism sound to it J
Some of us are also old enough to recall the similar confusion
between baud rate and bit rate in the good old dial-up modem days.
"Baud" was carried over from days of telegraph and it took a while
with internet access to move from baud to bit rate -- and then we
got that all mixed up with bandwidth.
So EPoC may be a good chance to set the record straight and take
the IEEE specs back to real engineering.
Either way I do not have a strong opinion but concur with Marek
that we need something unambiguous.
Rajeev
*From:* Hal Roberts [mailto:Hal.Roberts@xxxxxxxxx]
<mailto:[mailto:Hal.Roberts@xxxxxxxxx]>
*Sent:* Monday, August 20, 2012 6:06 PM
*To:* Jain, Rajeev; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* RE: [802.3_EPOC] EPoC Bandwidth Discussion
I agree with Rajeev,
Seems one can go with the traditional approach where bandwidth
refers to spectrum or adopt the more recent use of bandwidth for
data rate.
I have to side with the traditional approach. The term
"Band-Width" is pretty clear. There is a "band" (chunk of
spectrum) and it has a width associated with it.
It is unfortunate that the digital folks appropriated bandwidth
for data rate.
Just my opinion.
*From:* Jain, Rajeev [mailto:rajeevj@xxxxxxxxxxxx]
<mailto:[mailto:rajeevj@xxxxxxxxxxxx]>
*Sent:* Monday, August 20, 2012 8:02 PM
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Jorge, Marek,
Sorry to come late to the party but my vote is for "spectrum
bandwidth" in Hz when referring to the frequency bands in which we
transmit and "data rate" or "bit rate" in bps when referring the
rate at which bits are transmitted in that frequency band,
assuming that is consistent with EPON. I have also found that
bandwidth is used loosely and can be misconstrued when used in the
context of digital data transmission -- data/bit rate is explicit
is in this context. Adding the units to the definition will in any
case remove any ambiguity.
Cheers,
Rajeev
*From:* Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
<mailto:[mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]>
*Sent:* Monday, August 20, 2012 5:43 PM
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Sounds good. So, I think we are in agreement then. Let's use the
term bandwidth to mean data capacity, and not use it to mean RF
capacity. Instead, when referring to RF capacity we use the term
spectrum.
Does that make sense?
Thanks!
Jorge
*From*: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxxxxx]
<mailto:[mailto:marek.hajduczenia@xxxxxxxxx]>
*Sent*: Monday, August 20, 2012 08:27 PM
*To*: Salinger, Jorge; stds-802-3-epoc@xxxxxxxxxxxxxxxxx
<mailto:stds-802-3-epoc@xxxxxxxxxxxxxxxxx>
<stds-802-3-epoc@xxxxxxxxxxxxxxxxx
<mailto:stds-802-3-epoc@xxxxxxxxxxxxxxxxx>>
*Subject*: RE: [802.3_EPOC] EPoC Bandwidth Discussion
Jorge,
In EPON, we used term "bandwidth" in the meaning of "data rate" /
"channel capacity", which in the retrospect perhaps was not the
best idea. For example, we had statements like "Flexible
architecture allowing dynamic allocation of *_bandwidth_*", which
does not speak of spectrum allocation, but rather channel capacity
allocation. I could produce more examples where it is used in this
context, but I think you get the idea where it is going.
In general, EPON we only spoke of wavelength / wavelength band
allocation in Clause 75/60, which is effectively spectrum
allocation. However, the term used was "wavelength" and
"wavelength band/range".
Does this help ?
Marek
*From:* Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
<mailto:[mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]>
*Sent:* Tuesday, August 21, 2012 01:15
*To:* Marek Hajduczenia; stds-802-3-epoc@xxxxxxxxxxxxxxxxx
<mailto:stds-802-3-epoc@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Marek,
I understand.
So, how is the term bandwidth used in EPON parlance? I looked down
in the thread and can't see an example, but maybe I missed it.
Thanks!
Jorge
*From: *Marek Hajduczenia <marek.hajduczenia@xxxxxxxxx
<mailto:marek.hajduczenia@xxxxxxxxx>>
*Date: *Monday, August 20, 2012 8:08 PM
*To: *"Salinger, Jorge" <Jorge_Salinger@xxxxxxxxxxxxxxxxx
<mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx>>, EPoC Study Group
<STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>>
*Subject: *RE: [802.3_EPOC] EPoC Bandwidth Discussion
Jorge,
The only concern that I have with this is that multiple times we
speak of "bandwidth" without other denominators, leaving it open
to interpretation.
While I can certainly understand where Geoff would like us to go,
if we set different terminology from what was used in EPON before,
we will create a rift and people who understand EPON, will have to
get used to a different terminology for EPoC, something that I'd
rather (personally) avoid.
Marek
*From:* Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
*Sent:* Tuesday, August 21, 2012 01:04
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
All,
No quite being an RF guy, but having worked in the cable industry
for over 20 years... (for those thinking that I am old... I
started when I was 19 years old ;-)
My 2 cents...
I would propose that when speaking of RF capacity we refer to it
as spectrum. So, in the case of the discussion referenced by this
Email thread, we say "spectrum for EPoC" or "EPoC spectrum".
I think that the term bandwidth can be ambiguous unless it is used
in a specific context, such as "the bandwidth of an analog cable
channel is 6 MHz" and I also hear "the bandwidth of the highest
HSD tier is 300 Mbps".
Jorge
*From: *Duane Remein <Duane.Remein@xxxxxxxxxx
<mailto:Duane.Remein@xxxxxxxxxx>>
*Reply-To: *Duane Remein <Duane.Remein@xxxxxxxxxx
<mailto:Duane.Remein@xxxxxxxxxx>>
*Date: *Monday, August 20, 2012 1:15 PM
*To: *EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>>
*Subject: *Re: [802.3_EPOC] EPoC Bandwidth Discussion
Geoff,
I see your point, could we at least agree to preface there term
with "Spectra" when referring to RF (old habits, the only kind I
have at this point, die hard)?
Best Regards,
Duane
FutureWei Technologies Inc.
duane.remein@xxxxxxxxxx <mailto:duane.remein@xxxxxxxxxx>
Director, Access R&D
919 418 4741
Raleigh, NC
*From:* Geoff Thompson [mailto:thompson@xxxxxxxx]
*Sent:* Monday, August 20, 2012 1:04 PM
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Colleagues-
Just goes to show the extent to which Wikipedia is not an
authoritative source.
The answer to this question is obvious within the word itself.
Bandwidth is the width of the spectral band, i.e. it is an analog
measurement.
The so called "digital bandwidth" is not a bandwidth it is
"channel capacity" or "data rate" or "bit rate".
To illustrate how silly it is to use the spectral term for the
digital term just think of it in concrete terms.
You would never use the term "pavement width" when you mean "cars
per hour".
I took a brief tour of older clauses of 802.3 and the term is
mostly used correctly. There are several instances (which are
unfortunately duplicated in several places) where "bit rate" would
have been more accurate.
I would strongly prefer that we preserve its analog meaning and
use other appropriate terminology for digital rate measurement
(even if it means bucking current common terminology).
Geoff Thompson
On 208//12 9:22 AM, Hesham ElBakoury wrote:
Jim,
Wikipedia defines bandwidth as follows:
*Bandwidth* has several related meanings:
* Bandwidth (signal processing)
<http://en.wikipedia.org/wiki/Bandwidth_%28signal_processing%29>
or /analog bandwidth/, /frequency bandwidth/ or /radio
bandwidth/: a measure of the width of a range of
frequencies, measured in hertz
* Bandwidth (computing)
<http://en.wikipedia.org/wiki/Bandwidth_%28computing%29> or
/digital bandwidth/: a rate of data transfer, bit rate or
throughput, measured in bits per second (bps
Hesham
*From:* Jim Farmer [mailto:jfarmer@xxxxxxxxxx]
*Sent:* Monday, August 20, 2012 8:50 AM
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Unfortunately, as if often the case, we have multiple different
definitions for the same term -- as an RF nerd myself, I had
difficulty getting used to "bandwidth" referring to data. But the
data usage certainly is a common use of the term. If we need to
differentiate the two, I'd suggest the shorter term "RF bandwidth"
when we need to differentiate the two.
Thanks,
jim
Jim Farmer, K4BSE
Chief System Architect,
FTTP Solutions
Aurora Networks
1220 Old Alpharetta Rd.
Ste. 370
Alpharetta, GA 30005 USA
678-339-1045 (office)
678-640-0860 (mobile)
jfarmer@xxxxxxxxxx <mailto:jfarmer@xxxxxxxxxx>
*From:* Duane Remein [mailto:Duane.Remein@xxxxxxxxxx]
*Sent:* Monday, August 20, 2012 11:32 AM
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [802.3_EPOC] EPoC Bandwidth Discussion
Steve,
Your use ot the term "bandwidth" completely threw me, I've always
associated this term with data bandwidth.
Can I suggest we use something like Spectrum Channel Width --
defined as a portion of RF spectrum dedicated to a transmission
channel or sub-channel.
Once we agree on such a term Marek can then add this to the
definitions list.
Best Regards,
Duane
FutureWei Technologies Inc.
duane.remein@xxxxxxxxxx <mailto:duane.remein@xxxxxxxxxx>
Director, Access R&D
919 418 4741
Raleigh, NC
*From:* Shellhammer, Steve [mailto:sshellha@xxxxxxxxxxxx]
*Sent:* Friday, August 17, 2012 6:42 PM
*To:* STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
*Subject:* [802.3_EPOC] EPoC Bandwidth Discussion
EPoC Group,
Several of us had a good discussion on EPoC
bandwidth this morning. I would like to see if there are other
who would like to join us for future calls on Friday mornings (10
AM Pacific Time).
If anyone else would like to join us, please send
me an email and I will add you to the meeting invite.
Once we have some slides put together we will
review them on the Monday AM calls, hosted by Comcast.
Steve
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