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]
Sent: Tuesday, August 21, 2012 01:15
To: Marek Hajduczenia; 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>
Date: Monday, August 20, 2012 8:08 PM
To: "Salinger, Jorge" <Jorge_Salinger@xxxxxxxxxxxxxxxxx>, EPoC Study Group
<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
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>
Reply-To: Duane Remein <Duane.Remein@xxxxxxxxxx>
Date: Monday, August 20, 2012 1:15 PM
To: EPoC Study Group <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
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
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
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
From: Duane Remein [mailto:Duane.Remein@xxxxxxxxxx]
Sent: Monday, August 20, 2012 11:32 AM
To: 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
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
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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