This discussion has shown that definitions and understanding of low/mid/high split are not totally consistent within all in the industry and perhaps have changed over time.
In fact, I just looked at the CableLabs glossary found at
http://www.cablelabs.com/news/glossary/#H Here are the definitions found there:
Low Split
When upstream frequencies are assigned below 54MHz.
Mid Split
A frequency division scheme that allows bi-directional traffic on a single coaxial cable. Reverse channel signals propagate to the headend from 5 to 108 MHz. Forward path signals go from the headend from 162 MHz to the upper frequency limit. The duplex crossover
band is located from 108 to 162 MHz.
High Split
When the upstream frequencies are 5-150/174-750 MHz; this split provides the greatest amount of return path.
I realize some of these definitions in the glossary have been around for a while and may be “old” and perhaps not exactly the way some people use these terms today. I also do not know when the last update may have been made. I believe
the NCTA site at one time also had a glossary that was derived from the CableLabs glossary but I could not find it anymore on the NCTA website.
Given this is 2012 and we have the right industry minds engaging on this topic in this thread, I think we can arrive at consensus definitions for these terms.
Regards,
Victor
From: Matthew Schmitt [mailto:m.schmitt@xxxxxxxxxxxxx]
Sent: Tuesday, August 07, 2012 10:58 AM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
Jim,
Thanks for the additional information — that helps.
And FYI, completely understood about the caveat — it is something I am painfully aware of. :-)
Because of that, I would propose that our definitions just define the terms based on the top end of the upstream transmit range, and stay silent on the size of
the transition region or the low end of the forward path for each split. Would that work purely from a definition POV?
Thanks.
Matt
From:
Jim Farmer <jfarmer@xxxxxxxxxx>
Date: Tuesday, August 7, 2012 11:52 AM
To: Matthew Schmitt <m.schmitt@xxxxxxxxxxxxx>, "STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx" <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
The diagram reflects splits believed to be in use or proposed use at the time of publication. Of course, the industry’s plans change faster than you can publish
a book J, so you can certainly pick apart the frequencies shown. Treat them as examples. The
only caveat, to which both Tom and I alluded, is that the width of the transition region (“no man’s land”) is proportional to the frequency, so the higher you go, the more MHz you lose to the split. And there may be some implications in the complexity of
the CNT if you want it to have flexibility – it will take someone who has looked at that problem recently to answer that question.
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)
From: Matthew Schmitt [mailto:m.schmitt@xxxxxxxxxxxxx]
Sent: Tuesday, August 07, 2012 1:45 PM
To: Jim Farmer; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
Jim,
FYI, the progressive split move is just one idea — my main point is that not every MSO is necessarily looking at using the same split, and so some degree of flexibility
is going to be needed.
And thanks much for the diagram. One question, though: is it defining the splits to be just at very specific frequencies, or defining ranges of frequencies?
The diagram appears to be defining just specific frequencies, whereas I think that ranges make more sense given the desired flexibility. Thoughts?
Thanks.
Matt
From:
Jim Farmer <jfarmer@xxxxxxxxxx>
Date: Tuesday, August 7, 2012 11:34 AM
To: Matthew Schmitt <m.schmitt@xxxxxxxxxxxxx>, "STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx" <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
It is certainly possible to move the split from time to time. Each time you move it up, you open more bandwidth for the upstream, and I’m not sure with today’s
DSP and ASIC-based modulators, how the trade-off runs between complexity and the upstream bandwidth you can support. So there may be instances when you move to a higher upstream bandwidth and the older CNTs cannot follow you with more bandwidth. Of course,
presumably you could add new CNTs and take advantage of the higher bandwidth. Older units, if they tune to just above the split, would have to be able to move, but this is probably not a problem. So, yeah, I guess you could do as Matt says.
Regrettably, I have to give Mr. Large credit for the figure to which Tom refers, but it is attached.
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)
From: Matthew Schmitt [mailto:m.schmitt@xxxxxxxxxxxxx]
Sent: Tuesday, August 07, 2012 1:18 PM
To: Jim Farmer; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
Jim,
We've been investigating the topic of moving the split with our MSO members for some time, and one approach we've investigated is a progressive movement of the
split based on market needs,. In this scenario, an MSO would first move to a mid-split (in the range of 85-105, basically as much as you can do without impacting legacy set top boxes), and then potentially follow that by the move to a high-split if demand
warranted (200 MHz is the most commonly used number, although there's been some discussion of going even higher than that). Then again, some MSOs may not move the split at all, and others might jump directly to a high-split. The actual numbers may vary,
and whatever we define will need a good degree of flexibility.
But that's separate from the definitions.
To me, the simplest approach to the definition —and it matches a lot of recent papers, etc. -- is to use definitions along the line of what Jorge and others discussed
below: "sub-split" is when the upstream goes up to 42/65 MHz, "mid-split" is between 65 and around 108 MHz, and "high-split" is a return path that goes above that (but still stays below the forward path). That may not completely match some historical usage
of the terms, but does seem to match current usage. More detail than that seems to just get us into trouble. :-)
Thoughts?
Thanks.
Matt
From:
Jim Farmer <jfarmer@xxxxxxxxxx>
Date: Tuesday, August 7, 2012 11:07 AM
To: Matthew Schmitt <m.schmitt@xxxxxxxxxxxxx>, "STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx" <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
With either mid- or high-split, there should be no problem with an upper bound – the downstream band goes as far as you would like it to go. The only thing
that the split limits is the maximum upstream frequency and the minimum downstream frequency. A split in the 200 MHz region would work. Before stating something, I’d like to get inputs from MSOs as to what they want.
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)
From: Matthew Schmitt [mailto:m.schmitt@xxxxxxxxxxxxx]
Sent: Tuesday, August 07, 2012 1:02 PM
To: Jim Farmer; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
FYI, we've looked at "high split" options that put the top of the upstream at 200 MHz, with 40-50 MHz of transition (although that's pretty conservative). I
want to make sure we're not excluding that.
Maybe the proposed definition is getting lost across emails — would you be willing to restate your proposal completely?
Thanks.
Matt
From:
Jim Farmer <jfarmer@xxxxxxxxxx>
Reply-To: Jim Farmer <jfarmer@xxxxxxxxxx>
Date: Tuesday, August 7, 2012 10:38 AM
To: "STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx" <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
I imagine that an 18 MHz transition at those frequencies might be done today, maybe loosing a little to group delay. So I can support Tom’s proposal.
I believe that many European systems today do use an upstream band to 65 MHz. ANSI/SCTE 174 (RFoG) acknowledges a 65/85 split as well as an 85/105 split (both
20 MHz wide at lower frequencies). So those two are also known to be used.
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)
From: Tom Staniec [mailto:staniecjt@xxxxxxxxx]
Sent: Tuesday, August 07, 2012 12:03 PM
To: Jim Farmer; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Cc: staniecjt@xxxxxxxxx
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
I agree Jim. I expect the crossover to actually start at 168 MHz and go up, inferentially to channel 8 so there is 12 to 18 MHz spacing. On the bottom end,
there would be 6 MHz to play with which should assuage group delay on the top end of the return band. At any rate the downstream band towards the customers should be adjusted upward in frequency depending on the amount of dead space in the crossover of the
diplex filter.
Also we need to add a definition for the return in Europe which is 65 MHz if I recall. Someone correct me if I have that wrong.
Thanks
Tom
From: Jim Farmer [mailto:jfarmer@xxxxxxxxxx]
Sent: Tuesday, August 07, 2012 10:37 AM
To: Tom Staniec; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
I tend to agree with Tom, that we can omit the hyper split. There are too many other services contending for that spectrum. MoCA wants it, MSOs are talking
about going up in frequency for downstream signals, and there is a lot of plant out there in unknown condition at those frequencies. I’d be comfortable defining high split so that 174 MHz (bottom of RF channel 7) is the beginning of the downstream band.
I’m not sure that the upstream could extend to 168 MHz – that is kind of a small crossover region. If we were to scale the traditional 54/42 low split up to end at 174 MHz, we’d need a 38 MHz crossover region. This is probably more than we need. But if
we try to tighten the crossover too much, we are either going to get into complex, hard to stabilize filters, and/or we are going to start encountering group delay that makes the frequencies close to the crossover harder to use. The problem is somewhat better
than in the analog era thanks to adaptive equalization, but there are still laws of physics that must be obeyed.
Anyway, my idea is no hyper split, and a high split from, say, 144 MHz to 174 MHz. What do the MSOs want?
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)
From: Tom Staniec
[mailto:staniecjt@xxxxxxxxx]
Sent: Tuesday, August 07, 2012 8:08 AM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
Jorge
I think we can leave hyper split out. I added because what it demonstrates is how the upstream bands were defined along “natural points” of separation from
existing defined channel boundaries.
So let’s leave hyper split out.
In regard to high split, it might be wise to move the crossover up to at least the bottom edge of channel 7 (174.00 MHz).
I think for EPoC this actually might work nicely for the following reason: if the return is already occupied to 42 MHz then 174MHz – 42MHz = 132 MHz of approximately
“open spectrum.” If a symmetric 1Gb/s of capacity is required for EPoC then this crossover could allow it because we would have 120 MHz available.
That assumes diplex filter band edges extend down into the last channel in the mid-band (CH 22 – band edge 168 MHz) and up to channel 8 lower band edge of
180 Mhz. That will leave 126 MHZ of usable bandwidth for an EPoC carrier of 120 MHz/1 GB/s without touching what exists in the sub-low. Obviously once that bandwidth is in place (5 to 168 MHz), it can be carved up in a myriad of ways.
The above also assumes legacy set top boxes are retired so we are not trying to figure out ways to work around OOB (out of band) signals.
I offered my last email that Marek referred to only for consistency of definition. I hope this explanation works for everyone.
Tom
From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
Sent: Tuesday, August 07, 2012 2:42 AM
To: Tom Staniec; stds-802-3-epoc@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
Tom,
Thanks!
I think we agree with the definition of low/sub split and mid split, right?
For the definition of high split, do you think we need something other than "the cross-over is above 108 MHz"?
And, do you think we need to include the definition of hyper split? I'm not sure this is necessary, but I agree that it would not hurt to include it. If so, would
you mind suggesting a definition?
Thanks!
Jorge
From:
Tom Staniec <staniecjt@xxxxxxxxx>
Date: Monday, August 6, 2012 8:38 AM
To: "Salinger, Jorge" <Jorge_Salinger@xxxxxxxxxxxxxxxxx>, EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Cc: Tom Staniec <staniecjt@xxxxxxxxx>
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
All
Let’s try this a little differently. Sub, mid and high splits are all defined as an RF return where the upstream toward the head end or distribution hub and
away from the subscriber.
Sub split is fairly clear because the top end frequency for the band pass is always 40 to 42 MHz.
Mid split is actually a little more difficult to define but generally set the top end frequency of the return band pass at 108 MHz where the cross over frequency
was in, what cable referred to as the start of the mid-band (Channel 14 – bottom edge 120 MHz).
To Jorge’s point High split is a little more difficult. Also there was “one more split” which we haven’t discussed and frankly can leave alone: super or hyper
or equal (approximately assuming an RF amplifier with a 400 MHz top end).
High split was typically considered to have cross over point below VHF channel 7 – 174 MHz hence the reason it started at the bottom of VHF channel 7 in the
high band.
Super or Hyper – split was considered to be at or slightly below 220 MHz or above high band VHF channel 13.
As a point of note, the Super/Hyper/Equal roughly divided the upstream and downstream (toward the subscriber – away from the head end/distribution hub) as noted
with the caveat of the 400 MHz top end frequency.
It might be easier to craft the definitions we use around the frequency breakdowns shown above. Then the forward frequency use in each HFC network would, in
principle, be defined by the top end frequency of the fiber node or RF amplifier top frequency in conjunction with the coax spacing.
Tom
From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
Sent: Sunday, August 05, 2012 11:44 PM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
NOTE: I'm resending this Email without the diagram that Hesham had sent because the size of the Email exceeds the maximum Email size allowed by the Email reflector.
John,
I like your wording suggestion. Sounds much better than what I had, which now that I read it again sounded awkward as you said.
Marek,
If there is no further discussion, I suppose you will make the change in the definition, right?
Hesham,
I think we are saying the same thing, but in a different way. While there is agreement on the cross-over frequencies for low and mid-split systems, for the high split different folks consider different top ends, such as 200, 300 and even 400 MHz. But, what
we can all agree on is that the split is above 108 MHz, below which you would have a mid-split system. So, in the definition of high split, instead of referring to an absolute figure for the split as we did in low and mid-split systems, we just say "where
the split occurs above 108 MHz" (since there is no agreement on what that would be). Does that make sense?
Thanks!
Jorge
From: Hesham ElBakoury [mailto:Hesham.ElBakoury@xxxxxxxxxx]
Sent: Sunday, August 05, 2012 03:56 PM
To: John Ulm <julm@xxxxxxxxxxxx>; Salinger, Jorge
Cc: John T. Chapman <jchapman@xxxxxxxxx>; Emmendorfer, Mike <Mike.Emmendorfer@xxxxxxxxxx>
Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
I found the following illustration for the 4 types of split in a presentation by ARRIS that was presented by Dan Torbit in SCTE seminar on Engineering for All
IP.
Jorge was the moderator for this seminar.
It seems from this illustration that the high split crossover is 200MHZ instead of 108MHz.
John Chapman presentation in the last NCTA shows the following splits:
[JDS: I removed a diagram from Hesham's original Email to accommodate the size limit of the EPoC Email reflector]
I have seen other presentations from Cisco where high split crossover point is 200MHz (not 400MHz).
Is there a universal agreement on the definition of these splits ?
Thanks
Hesham
From: John Ulm [mailto:julm@xxxxxxxxxxxx]
Sent: Sunday, August 05, 2012 12:25 PM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
The wording on the High split definition comes across as a bit awkward. I'd suggest we mirror the wording for Mid split:
High split: an HFC network requiring a diplex filter in which the upstream
is transported in spectrum below the downstream, and where the cross-over
between the upstream and downstream occurs above 108 MHz
Does this work?
-- john
On Sun, Aug 5, 2012 at 10:17 AM, Salinger, Jorge <Jorge_Salinger@xxxxxxxxxxxxxxxxx> wrote:
Marek,
I think that after much discussion on the terms low, mid, high and top
split, we ended up with the definitions included below. I *think* that the
version you have in the list of terms that you just sent is not the latest
one. Hopefully I did not miss a later update, but please correct me if I
am wrong.
Regards,
Jorge
Low split: also known as sub-split, an HFC network requiring a diplex
filter in which the upstream is transported in spectrum below the
downstream, and where the cross-over between the upstream and downstream
occurs between 42 and 54 MHz in 6 MHz channel plan systems and between 65
and 85 MHz in 8 MHz channel plan systems
Mid split: also known as extended sub-split, an HFC network requiring a
diplex filter in which the upstream is transported in spectrum below the
downstream, and where the cross-over between the upstream and downstream
occurs between 85 and 108 MHz
High split: an HFC network requiring a diplex filter in which the upstream
is transported in spectrum below the downstream in spectrum above 108 MHz
Top split: an HFC network requiring a triplex filter in which there are
two upstream bands, one transported in spectrum below the downstream with
the cross-over as per either the low, mid or high splits defined above,
and another transported in spectrum above the downstream.
-----Original Message-----
From: Marek Hajduczenia <marek.hajduczenia@xxxxxx>
Reply-To: Marek Hajduczenia <marek.hajduczenia@xxxxxx>
Date: Sunday, August 5, 2012 8:45 AM
To: EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>Dear colleagues,
>
>The list of terms was updated, as shown in the attached document with
>tracked changes. Note specifically the extension in definitions of TDD and
>FDD and difference between these modes and half and full duplex, which I
>quote from the current version of P802.3bh (future 802.3-2012).
>
>I would also like to ask for input on missing terms and definitions. Is
>there any specific wording that you would like to see in the definition
>which is currently missing? If so, please do let me know.
>
>Thank you
>
>Marek
>
>-----Original Message-----
>From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxx]
>Sent: 26 July 2012 18:22
>To: 'STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx'
>Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
>
>Dear colleagues,
>
>Attached please find the updated version of the list of terms. If I do not
>hear any additional requests for new terms by Friday EBD, I would like to
>proceed to collect proposals for definitions, especially for terms which
>do
>not have currently any definitions assigned to them.
>
>Marek
>
>-----Original Message-----
>From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxx]
>Sent: 24 July 2012 07:27
>To: 'Duane Remein'; 'STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx'
>Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
>
>Duane,
>
>The 2008 version of the standard will be long gone by the time we get to
>any
>serious technical work, so the references were only incorrect indicating
>the
>standard's year.
>
>I believe some key terms should be included in the list, even if they just
>point to 802.3 specification, at least to prevent discussions on what is a
>single PHY, where people would interpret the term freely, in a manner not
>really consistent with 802.3 definitions
>
>Regards
>
>Marek
>
>-----Original Message-----
>From: Duane Remein [mailto:Duane.Remein@xxxxxxxxxx]
>Sent: 23 July 2012 12:15
>To: Marek Hajduczenia; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>Cc: Duane Remein
>Subject: RE: [802.3_EPOC] Action items for September 2012 meeting
>
>Marek,
>Give that this is a tool to help everyone learn the "proper" language I
>don't see the need not to copy definitions from 802.3. I've done that for
>all the "see Std IEEE 802.3-2008, 1.4.xx" references in the attached. Note
>that your references were incorrect, were you using clause numbering from
>the maintenance draft and not the 2008 edition as indicated?
>Best Regards,
>Duane
>
>FutureWei Technologies Inc.
>duane.remein@xxxxxxxxxx
>Director, Access R&D
>919 418 4741
>Raleigh, NC
>
>-----Original Message-----
>From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxx]
>Sent: Monday, July 23, 2012 10:48 AM
>To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>
>Jorge, et al.,
>
>Here is the updated list of terms accounting for recent discussions and
>suggestions.
>
>I am off hiking
>
>Marek
>
>-----Original Message-----
>From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
>Sent: 23 July 2012 07:40
>To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>
>All,
>
>Based on everyone's comments, I would suggest the following definitions:
>
>HFC: a hybrid fiber-coax cable network, in which fiber is used to transmit
>analog RF signals (note: this definition excludes the case where we have
>digital return, but I think that's OK)
>
>Low split: also known as sub-split, an HFC network requiring a diplex
>filter
>in which the upstream is transported in spectrum below the downstream, and
>where the split between the upstream and downstream occurs below 42 MHz
>in 6
>MHz channel plan systems and 65 MHz in 8 MHz channel plan systems
>
>Mid split: also known as extended sub-split, an HFC network requiring a
>diplex filter in which the upstream is transported in spectrum below the
>downstream, and where the split between the upstream and downstream occurs
>below 108 MHz
>
>High split: an HFC network requiring a diplex filter in which the upstream
>is transported in spectrum below the downstream, and where the split
>between
>the upstream and downstream occurs below 216 MHz
>
>Top split: an HFC network requiring a triplex filter in which there are
>two
>upstream bands, one transported in spectrum below the downstream occupying
>spectrum as per either the low, mid or high splits defined above, and
>another transported in spectrum above the downstream.
>
>
>Regards,
>Jorge
>
>-----Original Message-----
>From: Tom Staniec <staniecjt@xxxxxxxxx>
>Reply-To: Tom Staniec <staniecjt@xxxxxxxxx>
>Date: Monday, July 23, 2012 9:00 AM
>To: EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>
>>Good morning all
>>
>>I want to point to some historical perspective on the topics below.
>>
>>Historically:
>>
>>SUB-SPLIT: defined as a cross over point of 42 MHz where the sub-low
>>return is below 42 MHz with the forward being above.
>>
>>That places an EXTENDED SUB Split at 88 MHz, the start of the FM radio
>>band, where everything below 88 MHz would represent return and
>>everything above
>>88
>>MHz is the forward.
>>
>>MID-SPLIT defined the cross over point of the diplex filter as 108 MHz
>>where everything below 108 MHz represents the return band. Everything
>>above 108 MHz represents the forward.
>>
>>HIGH SPLIT is a little more difficult to define. Traditionally the high
>>split was placed above channel 13 top end frequency is 216 MHz where
>>everything below 216 MHz is return and above is forward network.
>>
>>TOP SPLIT is interesting and, again, historically first appeared as a
>>result of TWC FSN (Full Service Network - if my memory is correct) a
>>proof of concept network built in Orlando, Florida but was referred to,
>>in my recollection, as HIGH RETURN. So I think we need to rethink and
>>reflect on how this is described. To Jeff's point, today this reflects
>>a "tri-plex filtering system.
>>
>>Incidentally, HIGH RETURN, at the time was considered not feasible for
>>use for 2 reasons: 1- it placed a top end limit on what cable operators
>>could offer for services and limited channel growth and 2- it required
>>too much power to operate a return in for a communications channel.
>>With everything moving to an IP delivery which frankly could mean
>>unbounded channels the capacity limit in number 1 above may be moot. As
>>for number 2, because power amplifier technology has evolved along with
>>modulation, detection and error correction schemes, this may be more
>>attainable but also may require significant changes in network
>>architecture.
>>
>>I hope this presents some perspective which we may want to follow for
>>consistency at this point.
>>
>>Regards
>>Tom
>
>
>-----Original Message-----
>From: <Finkelstein>, Jeff Finkelstein <Jeff.Finkelstein@xxxxxxx>
>Reply-To: Jeff Finkelstein <Jeff.Finkelstein@xxxxxxx>
>Date: Sunday, July 22, 2012 11:03 PM
>To: EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>
>>To me top-split means a triplex scenario where a second split goes
>>above the downstream, not necessarily only for an upstream but that is
>>how we typically view it.
>>
>>Some scenarios have a legacy upstream being below the downstream, then
>>a second upstream being above the downstream spectrum. I think this is
>>what has been referred to as top-split in respect to this discussion.
>>
>>________________________________________
>>From: Noll, Kevin [kevin.noll@xxxxxxxxxxx]
>>Sent: Sunday, July 22, 2012 10:47 PM
>>To: Finkelstein, Jeff (CCI-Atlanta);
STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>>
>>I have always understood top-split to mean that the upstream goes above
>>the currently designed upper plant limits. Usually this means >750MHz
>>or in some contexts >1GHz. Agreed that it isn't always clear on the
>>exact frequency, but it is clear that it is higher than a high-split.
>>
>>--kan--
>>
>
>
>
>>-----Original Message-----
>>From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxxxxx]
>>Sent: Monday, July 23, 2012 1:30 AM
>>To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>>
>>Jorge,
>>
>>I included both proposed definitions. Until clarification on the use of
>>top-split is made, I will keep the term in the list tentatively and
>>follow the discussion.
>>
>>Marek
>
>
>-----Original Message-----
>From: <Kelsen>, Mike Kelsen <michael.kelsen@xxxxxxxxxxx>
>Date: Sunday, July 22, 2012 4:32 PM
>To: "Salinger, Jorge" <Jorge_Salinger@xxxxxxxxxxxxxxxxx>
>Cc: EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>
>>Jorge,
>>
>>I'd lean towards #1 and keep the top split definition even if just to
>>say it was considered and dropped for various reasons.
>>
>>-Mike
>>
>
>
>>
>>-----Original Message-----
>>From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
>>Sent: 22 July 2012 10:28
>>To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>>
>>Marek,
>>
>>I think I would correct the definitions of Mid- and High-split, as
>>follows:
>>
>>Mid split: an HFC network in which the split between the upstream and
>>downstream occurs between 65 and 100 MHz
>>
>>High split: an HFC network in which the split between the upstream and
>>downstream occurs above 100 MHz
>>
>>I still have some concern about a conflict between the definitions of
>>High-
>>and Top-split since they could overlap. Maybe we could solve it in one
>>of two ways: 1. add something like "the upstream transmission occupies
>>spectrum below the downstream" for low-, mid- and high-split
>>definitions, or 2. Get rid of the top-split altogether since we won't
>>be considering that option (as we discussed in the meeting in San
>>Diego).
>>
>>I wonder what others, especially my MSO/CL colleagues, think.
>>
>>Thanks!
>>Jorge
>>
>>
>>----- Original Message -----
>>From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]
>>Sent: Sunday, July 22, 2012 12:14 PM
>>To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
>><STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
>>Subject: Re: [802.3_EPOC] Action items for September 2012 meeting
>>
>>Marek,
>>
>>To add to your list, here is a start for the definitions for the
>>various splits, and one additional definition (HFC):
>>
>>HFC: a hybrid fiber-coax cable network, in which fiber is used to
>>transmit analog RF signals (note: this definition excludes the case
>>where we have digital return, but I think that's OK)
>>
>>Low split: an HFC network in which the split between the upstream and
>>downstream occurs below 65 MHz
>>
>>Mid split: an HFC network in which the split between the upstream and
>>downstream occurs below 100 MHz
>>
>>High split: an HFC network in which the split between the upstream and
>>downstream occurs below 200 MHz
>>
>>
>>Top split: an HFC network in which the upstream is placed above the
>>downstream
>>
>>Hope this helps.
>>
>>Jorge
>>
>>
>>
>>-----Original Message-----
>>From: Marek Hajduczenia <marek.hajduczenia@xxxxxx>
>>Reply-To: Marek Hajduczenia <marek.hajduczenia@xxxxxx>
>>Date: Thursday, July 19, 2012 3:48 PM
>>To: EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
>>Subject: [802.3_EPOC] Action items for September 2012 meeting
>>
>>>Dear colleagues,
>>>
>>>Following the discussion in the morning, focused on the preparation
>>>for September 2012 meeting, I would like to start discussion on
>>>terminology for EPoC, as attached to this email. What I did so far,
>>>was to go through the contributions discussed so far, to collect the
>>>terms which were used most commonly in presentations and discussions,
>>>with the special focus on terms generating heated discussions
>>>(infamous
>PHY).
>>>The content is colour coded:
>>>
>>>- a term in green indicates that we have already a solid definition in
>>>802.3, which ought to be reused without changes
>>>- a term in yellow indicates a term which is specific to EPoC, and I
>>>felt sufficiently capable to propose the pass at the definition
>>>- a term in red indicates a wording which I collected from one of
>>>contributions, but it requires either further discussion,
>>>clarification or confirmation whether it is needed at all.
>>>
>>>In the first pass through the list, please indicate whether any
>>>critical terms are missing or unnecessary. My intent at this time is
>>>to collect a complete list of terms, before we plunge into producing
>>>missing definitions.
>>>Please keep all discussion on the reflector so that we do not talk
>>>past each other or repeat proposals. I will try to keep the list
>>>updated as frequently as needed.
>>>
>>>Given that definitions are critical for technical discussions on
>>>individual proposals, I'd suggest we complete the phase of collecting
>>>terms by the 28th of July, at which time I will move to generating
>>>individual missing definitions.
>>>
>>>Regards
>>>
>>>Marek
>>>
>>>______________________________________________________________________
>>>_
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>>>
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>>
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