Re: [802.3_100GNGOPTX] Emerging new reach space
Hi Winston,
I have solicited input integration architects from HP, IBM and Dell in
addition to a couple of large IT integrators.
So far, no response. If someone has a direct contact at one of the large
integration service providers (note: Not just an employee, but someone who
actually architects large IT solutions), please forward me their contact
info or introduce us via email.
Best Regards,
Dan
On 11/19/11 9:26 AM, "Winston Way" <winston.way@xxxxxxxxxxxxxxxx> wrote:
>That is why I have suggested to Dan that we invite data center users such
>as Google, Amazon, Microsoft, HP, etc., to let us know their real need in
>the near future.
>We need first-hand information from these end users! I recall that there
>were a number of end users invited to HSSG meetings in 2008, and those
>first-hand information was very useful.
>
>Winston
>
>-----Original Message-----
>From: Jonathan King [mailto:jonathan.king@xxxxxxxxxxx]
>Sent: Friday, November 18, 2011 6:35 PM
>To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>
>I'm not sure that measuring the outside of a building tells you much
>about link length distributions unless you also know what the data center
>architecture is inside the building.
>
>I would guess that very very large data centers would have a more
>modular architecture, to make build, bring up, and operations more
>scalable.
>
>Maybe we should consult an expert ?
>
>
>
>-----Original Message-----
>From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxx]
>Sent: Friday, November 18, 2011 5:18 PM
>To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>
>Jeff
>
>In Chicago presentation I do identify several mega data centers larger
>than 400,000 sq-ft, one possibly as large as
>1000,000 sq-ft.
>http://www.ieee802.org/3/100GNGOPTX/public/sept11/ghiasi_01_a_0911_NG100GO
>PTX.pdf
>
>Thanks,
>Ali
>
>On Nov 18, 2011, at 5:04 PM, Jeffery Maki wrote:
>
>> Scott,
>>
>> Was the choice to end your table at 400,000 sq. ft. arbitrary?
>>
>> All,
>>
>> I believe we need to know if the potential square footage may or may
>>not grow larger over the coming years for what is known as a mega
>>datacenter. How big is a mega datacenter to be? At some point,
>>100GBASE-LR4 will be the right choice just based on loss budget. We
>>need to know the distribution of reaches to understand where to draw the
>>line in selecting a break in the PMD definitions.
>>
>> Jeff
>>
>>
>> -----Original Message-----
>> From: Scott Kipp [mailto:skipp@xxxxxxxxxxx]
>> Sent: Friday, November 18, 2011 1:38 PM
>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>
>> Chris and all,
>>
>> I have been wanting to discuss the reach objective for 100GBASE-nR4, so
>>thanks for kicking off this discussion.
>>
>> You referenced the 10X10 MSA white paper that calls out a maximum
>>distance of <500 meters. You reference the authors of Vijay and Bikash,
>>but I was the co-author that wrote this section of the paper and did the
>>mathematical analysis which they agreed to. The actual distance of 414
>>meters is a simple calculation based on a 400,000 sq ft data center.
>>Even if the data center is 550,000 sq ft, the link distance is less than
>>500 meters long. So I propose that 500 meters is long enough for the
>>largest data centers that we should target.
>>
>> The problem with a 500 meter distance is in the way that the IEEE
>>defines the maximum link length. The IEEE defines the reach objective
>>for SM fibers and gives an insertion loss based on the 2.0dB of
>>connector and splice loss and the fiber attenuation loss. Specifically,
>>802.3ba states this below table 87.9:
>>
>> The channel insertion loss is calculated using the maximum distance
>> specified in Table 87–6 and cabled optical fiber attenuation of 0.47
>>dB/km at 1264.5 nm plus an allocation for connection and splice loss
>>given in 87.11.2.1.
>>
>> For the 10km link of 100GBASE-LR4, the attenuation is 6.7dB = 10km *
>>0.47dB/km + 2.0dB of connector and splice loss.
>>
>> If this project follows this example for a 500 meter nR4 link, then the
>>insertion loss would only be 2.2dB = 0.5km * 0.47dB/km + 2.0dB for
>>connector and splice loss. Many attendees know that this could limit the
>>applicability of the nR4 link because it won't support structured
>>cabling environments. With many MPO ribbon connectors in a link, it
>>could be difficult to support a typical link in the structured cabling
>>environments that will be required in large data centers.
>>
>> To make nR4 a success, we need to take these structured cabling
>>environments into account and increase the connector loss. I would like
>>to hear from some cabling vendors and especially end users as to range
>>of insertion losses that they have seen and what they expect to see if
>>ribbon fibers are used instead of the usual duplex SM fibers.
>>
>> Jonathan King did a great statistical analysis of 4 duplex MM
>>connection loss in king_01_0508. We should do a similar analysis for 6
>>SM ribbon connectors to determine the loss of a long link.
>>
>> If we determine the loss to be 3.5dB, then the insertion loss for the
>>nR4 link could be 3.7dB = 0.5km * 0.47dB/km + 3.5dB for connector and
>>splice loss. With these parallel solutions, this loss might even be
>>larger since they don't have the WDM losses in the link.
>>
>> That's my 42 cents,
>> Scott
>>
>>
>> -----Original Message-----
>> From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
>> Sent: Friday, November 18, 2011 11:12 AM
>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>
>> Jack,
>>
>> Thank you for continuing to lead the discussion. I am hoping it
>>encourages others to jump in with their perspectives, otherwise you will
>>be stuck architecting the new standard by yourself with the rest of us
>>sitting back and observing.
>>
>> Your email is also a good prompt to start discussing the specific reach
>>objective for 100GE-nR4. Since you mention 2000m reach multiple times in
>>your email, can you give a single example of a 2000m Ethernet IDC link?
>>
>> I am aware of many 150m to 600m links, with 800m mentioned as long term
>>future proofing, so rounding up to 1000m is already conservative. I
>>understand why several IDC operators have asked for 2km; it was the next
>>closest existing standard reach above their 500m/600m need; see for
>>example page 10 of Donn Lee's March 2007 presentation to the HSSG
>>(http://www.ieee802.org/3/hssg/public/mar07/lee_01_0307.pdf). It is very
>>clear what the need is, and why 2km is being brought up.
>>
>> Another example of IDC needs is in a 10x10G MSA white paper
>>(http://www.10x10msa.org/documents/10X10%20White%20Paper%20final.pdf),
>>where Bikash Koley and Vijay Vusirikala of Google show that their
>>largest data center requirements are met by a <500m reach interface.
>>
>> In investigating the technology for 100GE-nR4, we may find as Pete
>>Anslow has pointed out in NG 100G SG, that the incremental cost for
>>going from 1000m to 2000m is negligible. We may then chose to increase
>>the standardized reach. However to conclude today that this is in fact
>>where the technology will end up is premature. We should state the reach
>>objective to reflect the need, not our speculation about the
>>capabilities of yet to be defined technology.
>>
>> Thank you
>>
>> Chris
>>
>> -----Original Message-----
>> From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx]
>> Sent: Friday, November 18, 2011 9:38 AM
>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>
>> Hello All,
>> Thanks for all the contributions to this discussion. Here's a synopsis
>> and my current take on where it's heading (all in the context of
>> 150-2000m links).
>> Starting Point: Need for significantly-lower cost/power links over
>> 150-2000m reaches has been expressed for several years. Last week in
>> Atlanta, four technical presentations on the subject all dealt with
>> parallel SMF media. Straw polls of "like to hear more about ___"
>> received 41, 48, 55, and 48 votes, the 41 for one additionally
>>involving new fiber.
>> The poll "to encourage more on…duplex SMF PMDs" received 35 votes.
>> Another straw poll gave strong support for the most-aggressive low-cost
>>target.
>> Impressions from discussion and Atlanta meeting: Systems users
>> (especially the largest ones) are strongly resistant to adopting
>> parallel SMF. (not addressing reasons for that position, just stating
>> an observation.) LR4 platform can be extended over duplex SMF via WDM
>> by at least one more "factor-4" generation, and probably another (DWDM
>> for latter); PAM and line-rate increase may extend duplex-SMF's
>> lifetime yet another generation.
>> My Current Take: Given a 2-or-3-generation (factor-4; beyond
>> 100GNGOPTX) longevity of duplex SMF, I'm finding it harder to make a
>> compelling case for systems vendors to adopt parallel SMF for
>> 100GNGOPTX. My current expectation is that duplex SMF will be the
>> interconnection medium. My ongoing efforts will have more duplex-SMF
>> content. I still think parallel SMF should deliver lowest cost/power
>> for 100GNGOPTX, and provide an additional 1-2 generations of
>> longevity; just don't see system vendors ready to adopt it now.
>> BUT: What about the Starting Point (above), and the need for
>> significantly-lower cost/power?? If a compelling case is to be made
>> for an alternative to duplex SMF, it will require a very crisp and
>> convincing argument for significantly-lower cost/power than LR4
>> ("fair" comparison such as mentioned earlier), or other duplex SMF
>> approaches. Perhaps a modified version of LR4 can be developed with
>> lower-cost/power lasers that doesn't reach 10km. If, for whatever
>> reasons, systems vendors insist on duplex SMF, but truly need
>> significantly-lower cost/power, it may require some compromise, e.g.
>> "wavelength-shifted" SMF, or something else. Would Si Photonics really
>> satisfy the needs with no compromise? Without saying they won't, it
>> seems people aren't convinced, because we're having these discussions.
>> Cheers, Jack
>>
>>
>> On 11/17/11 10:23 AM, "Arlon Martin" <amartin@xxxxxxxxxx> wrote:
>>
>>> Hello Jack,
>>> To your first question, yes, we are very comfortable with LAN WDM
>>> spacing. That never was a challenge for the technology. We have
>>> chosen to perfect reflector gratings because of the combination of
>>> small size and great performance. I am not sure exactly what you are
>>> asking in your second question. There may be a slightly lower loss to
>>> AWGs than reflector gratings. That difference has decreased as we
>>> have gained more experience with gratings. For many applications like
>>> LR and mR, the much, much smaller size (cost is related to size) of
>>> reflector gratings makes them the best choice.
>>>
>>> Thanks, Arlon
>>>
>>> -----Original Message-----
>>> From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx]
>>> Sent: Thursday, November 17, 2011 6:42 AM
>>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>>
>>> Hi Arlon,
>>> Thanks very much for this. You are right; I was referring to thin
>>> film filters. My gut still tells me that greater tolerances should
>>> accompany wider wavelength spacing. So I'm guessing that your
>>> manufacturing tolerances are already "comfortable" at the LAN WDM
>>> spacing, and thus the difference is negligible to you. Is that a fair
>>> statement? Same could be true for thin film filters. At any rate, LAN
>>> WDM appears to have one
>>> factor-4 generation advantage over CWDM in this discussion, and it's
>>> good to hear of its cost effectiveness. Which brings up the next
>>> question. Your data on slide 15 of Chris's presentation referenced in
>>> his message shows lower insertion loss for your array waveguide (AWG)
>>> DWDM filter than for the grating filters. Another factor-of-4 data
>>> throughput may be gained in the future via DWDM.
>>> Cheers, Jack
>>>
>>> On 11/16/11 10:51 PM, "Arlon Martin" <amartin@xxxxxxxxxx> wrote:
>>>
>>>> Hello Jack,
>>>> As a maker of both LAN WDM and CWDM filters, I would like to comment
>>>> on the filter discussion. WDM filters can be thin film filters (to
>>>> which you may be referring) but more likely, they are PIC-based AWGs
>>>> or PIC-based reflector gratings. In our experience at Kotura with
>>>> reflector gratings made in silicon, both CWDM and LAN WDM filters
>>>> work equally well and are roughly the same size. It is practical to
>>>> put 40 or more wavelengths on a single chip. We have done so for
>>>> other applications. There is plenty of headroom for more channels
>>>>when the need arises for 400 Gb/s or 1 Tbs.
>>>> There may be other reasons to select CWDM over LAN WDM, but, in our
>>>> experience, filters do not favor one choice over the other.
>>>>
>>>> Arlon Martin, Kotura
>>>>
>>>> -----Original Message-----
>>>> From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx]
>>>> Sent: Wednesday, November 16, 2011 9:09 PM
>>>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>>>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>>>
>>>> Thanks Chris for your additions.
>>>> 1. "CWDM leads to simpler optical filters versus "closer" WDM (LAN
>>>>WDM)"
>>>> -
>>>> For a given throughput transmission and suppression of
>>>> adjacent-wavelength signals (assuming use of same available optical
>>>> filter materials), use of a wider wavelength spacing can be
>>>> accomplished with wider thickness tolerance and usually with fewer
>>>> layers. The wider thickness tolerance is basic physics, with which I
>>>> won't argue. In this context, I consider "wider thickness tolerance"
>>>> as "simpler."
>>>> 2. "CWDM leads to lower cost versus "closer" WDM because cooling is
>>>> eliminated" - I stated no such thing, though it's a common perception.
>>>> Ali
>>>> Ghiasi suggested CWDM (implied by basing implementation on
>>>> 40GBASE-LR4) might be lower cost, without citing the cooling issue.
>>>> Cost is a far more complex issue than filter simplicity. You made
>>>> excellent points regarding costs in your presentation cited for
>>>> point 1, and I cited LAN WDM
>>>> (100GBASE-LR4) advantages as "better-suited-for-integration, and
>>>> "clipping off" the highest-temp performance requirement." We must
>>>> recognize that at 1km vs 10km, chirp issues are considerably
>>>> reduced.
>>>> 3. "CWDM is lower power than "closer" WDM power" - I stated no such
>>>> thing, though it's a common perception. I did say "More wavelengths
>>>> per fiber means more power per channel," which is an entirely
>>>> different statement, and it's darned hard to argue against the
>>>> physics of it (assuming same technological toolkit).
>>>> All I stated in the previous message are the advantages of CWDM
>>>> (adopted by 40GBASE-LR4) and LAN WDM (adopted by 100GBASE-LR4),
>>>> without favoring one over the other for 100GbE (remember we're
>>>>talking ~1km, not 10km).
>>>> But
>>>> my forward-looking (crude) analysis of 400GbE and 1.6TbE clearly
>>>> favors LAN WDM over CWDM - e.g. "CWDM does not look attractive on
>>>> duplex SMF beyond 100GbE," whereas the wavelength range for 400GbE
>>>> LAN 16WDM over duplex SMF "is realistic." Quasi-technically speaking
>>>> Chris, we're on the same wavelength (pun obviously intended) :-)
>>>> Paul Kolesar stated the jist succinctly: "that parallel fiber
>>>> technologies appear inevitable at some point in the evolution of
>>>> single-mode solutions.
>>>> So the question becomes a matter of when it is best to embrace
>>>> them." [I would replace "inevitable" with "desirable."] From a
>>>> module standpoint, it's easier, cheaper, lower-power to produce a
>>>> x-parallel solution than a x-WDM one (x is number of channels), and
>>>> it's no surprise that last week's technical presentations (by 3
>>>> module vendors and 1 independent) had a parallel-SMF commonality for
>>>> 100GNGOPTX. There is a valid argument for initial parallel SMF
>>>> implementation, to be later supplanted by WDM, particularly LAN WDM.
>>>> With no fiber re-installations.
>>>> To very recent messages, we can choose which pain to feel first,
>>>> parallel fiber or PAM, but by 10TbE we're likely get both - in your
>>>> face or innuendo :-) Jack
>>>>
>>>>
>>>>
>>>> On 11/16/11 6:53 PM, "Chris Cole" <chris.cole@xxxxxxxxxxx> wrote:
>>>>
>>>>> Hello Jack,
>>>>>
>>>>> You really are on a roll; lots of insightful perspectives.
>>>>>
>>>>> Let me clarify a few of items so that they don't detract from your
>>>>> broader ideas.
>>>>>
>>>>> 1. CWDM leads to simpler optical filters versus "closer" WDM (LAN
>>>>> WDM)
>>>>>
>>>>> This claim may have had some validity in the past, however it has
>>>>> not been the case for many years. This claim received a lot of
>>>>> attention in 802.3ba TF during the 100GE-LR4 grid debate. An
>>>>> example presentation is
>>>>> http://www.ieee802.org/3/ba/public/mar08/cole_02_0308.pdf, where on
>>>>> pages 13, 14, 15, and 16 multiple companies showed there is no
>>>>> practical implementation difference between 20nm and 4.5nm spaced
>>>>>filters.
>>>>> Further,
>>>>> this has now been confirmed in practice with 4.5nm spaced LAN WDM
>>>>> 100GE-LR4 filters in TFF and Si technologies manufactured with no
>>>>> significant cost difference versus 20nm spaced CWDM 40GE-LR4 filters.
>>>>>
>>>>> If there is specific technical information to the contrary, it
>>>>> would be helpful to see it as a presentation in NG 100G SG.
>>>>>
>>>>> 2. CWDM leads to lower cost versus "closer" WDM because cooling is
>>>>> eliminated
>>>>>
>>>>> This claim has some validity at lower rates like 1G or 2.5G, but is
>>>>> not the case at 100G. This has been discussed at multiple 802.3
>>>>> optical track meetings, including as recently as the last NG 100G
>>>>> SG meeting. We again agreed that the cost of cooling is a fraction
>>>>> of a percent of the total module cost. Even for a 40GE-LR4 module,
>>>>> the cost of cooling, if it had to be added for some reason, would
>>>>> be insignificant. Page 4 of the above
>>>>> cole_02_0308 presentation discusses why that is.
>>>>>
>>>>> This claim to some extent defocuses from half a dozen other cost
>>>>> contributors which are far more significant. Those should be at the
>>>>> top of the list instead of cooling. Further, if cooling happens to
>>>>> enable a technology which reduces by a lot a significant cost
>>>>> contributor, then it becomes a big plus instead of an insignificant
>>>>> minus.
>>>>>
>>>>> If there is specific technical information to the contrary, a NG
>>>>> 100G SG presentation would be a great way to introduce it.
>>>>>
>>>>> 3. CWDM is lower power than "closer" WDM power.
>>>>>
>>>>> The real difference between CWDM and LAN DWDM is that un-cooled is
>>>>> lower power. However how much lower strongly depends on the
>>>>> specific transmit optics and operating conditions. In 100G module
>>>>> context it can be 10% to 30%. However, for some situations it could
>>>>> be a lot more savings, and for others even less. No general
>>>>> quantification of the total power savings can be made; it has to be
>>>>> done on a case by case basis.
>>>>>
>>>>> Chris
>>>>>
>>>>> -----Original Message-----
>>>>> From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx]
>>>>> Sent: Wednesday, November 16, 2011 3:20 PM
>>>>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>>>>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>>>>
>>>>> Great inputs! :-)
>>>>> Yes, 40GBASE-LR4 is the first alternative to 100GBASE-LR4 that
>>>>> comes to mind for duplex SMF. Which begs the question: why are they
>>>>> different?? I can see advantages to either: (40G CWDM vs 100G
>>>>> closerWDM) - uncooled, simple optical filters vs
>>>>>better-suited-for-integration, and "clipping"
>>>>> off" the highest-temp performance requirement.
>>>>> It's constructive to look forward, and try to avoid unpleasant
>>>>> surprises of "future-proof" assumptions (think 802.3z and FDDI
>>>>> fiber - glad I wasn't there!). No one likes "forklift upgrades"
>>>>> except maybe forklift operators, who aren't well-represented here.
>>>>> Data centers are being built, so here's a chance to avoid
>>>>> short-sighted mistakes. How do we want 100GbE, 400GbE and 1.6TbE to
>>>>> look (rough guesses at the next generations)? Here are 3 basic
>>>>> likely scenarios, assuming (hate to, but must) 25G electrical
>>>>> interface and no electrical mux/demux. Considering duplex SMF,
>>>>> 4+4parallel
>>>>> SMF, and 16+16parallel SMF:
>>>>> Generation
>>>>> 100GbE duplex-SMF / 4WDM 4+4parallel / no WDM
>>>>> 16+16parallel / dark fibers
>>>>> 400GbE duplex-SMF / 16WDM 4+4parallel / 4WDM
>>>>> 16+16parallel / no WDM
>>>>> 1.6TbE duplex-SMF / 64WDM 4+4parallel / 16WDM
>>>>> 16+16parallel / 4WDM
>>>>> The above is independent of distances in the 300+ meter range we're
>>>>> considering. Yes, there are possibilities of PAM encoding and
>>>>> electrical interface speed increases. Historically we've avoided
>>>>> the former, and the latter is expected to bring a factor of 2, at
>>>>> most, for these generations.
>>>>> Together, they might bring us forward 1 factor-of-4 generation
>>>>>further.
>>>>> For 40GbE or 100GbE, 20nm-spaced CWDM is nice for 4WDM (4
>>>>>wavelengths).
>>>>> At
>>>>> 400GbE, 16WDM CWDM is a 1270-1590nm stretch, with 16 laser products
>>>>> (ouch!). 20nm spacing is out of the question for 64WDM (1.6TbE).
>>>>> CWDM does not look attractive on duplex SMF beyond 100GbE.
>>>>> OTOH, a 100GBASE-LR4 - based evolution on duplex SMF, with ~4.5nm
>>>>> spacing, is present at 100GbE. For 400GbE, it could include the
>>>>> same 4 wavelengths, plus 4-below and 12-above - a 1277.5-1349.5nm
>>>>> wavelength span, which is realistic. The number of "laser products"
>>>>> is fuzzy, as the same epitaxial structure and process (except
>>>>> grating spacing) may be used for maybe a few, but nowhere near all,
>>>>> of the wavelengths. For 1.6TbE 64WDM, LR4's 4.5nm spacing implies a
>>>>> 288nm wavelength span and a plethora of "laser products."
>>>>> Unattractive.
>>>>> On a "4X / generational speed increase," 4+4parallel SMF gains one
>>>>> generation over duplex SMF and 16+16parallel SMF gains 2
>>>>> generations over duplex SMF. Other implementations, e.g. channel
>>>>> rate increase and/or encoding, may provide another generation or
>>>>> two of "future accommodation."
>>>>> The larger the number of wavelengths that are multiplexed, the
>>>>> higher the loss budget that must be applied to the
>>>>> laser-to-detector (TPlaser to
>>>>> TPdetector) link budget. More wavelengths per fiber means more
>>>>> power per channel, i.e. more power/Gbps and larger faceplate area.
>>>>> While duplex SMF looks attractive to systems implementations, it
>>>>> entails significant(!!) cost implications to laser/transceiver
>>>>> vendors, who may not be able to bear "cost assumptions," and
>>>>> additional power requirements, which may not be tolerable for
>>>>> systems vendors.
>>>>> I don't claim to "have the answer," rather attempt to frame the
>>>>> question pointedly "How do we want to architect the next few
>>>>> generations of Structured Data Center interconnects?" Insistence on
>>>>> duplex SMF works for this-and-maybe-next-generation, then may hit a
>>>>> wall. Installation of parallel SMF provides a 1-or-2-generation-gap
>>>>> of "proofing," with higher initial cost, but with lower power
>>>>> throughout, and pushing back the need for those abominable
>>>>> "forklift upgrades."
>>>>> Jack
>>>>>
>>>>>
>>>>> On 11/16/11 1:00 PM, "Kolesar, Paul" <PKOLESAR@xxxxxxxxxxxxx> wrote:
>>>>>
>>>>>> Brad,
>>>>>> The fiber type mix in one of my contributions in September is all
>>>>>> based on cabling that is pre-terminated with MPO(MTP)array
>>>>>>connectors.
>>>>>> Recall
>>>>>> that single-mode fiber represents about 10 to 15% of those channels.
>>>>>> Such cabling infrastructure provides the ability to support either
>>>>>> multiple 2-fiber or parallel applications by applying or removing
>>>>>> fan-outs from the ends of the cables at the patch panels. The
>>>>>> fan-outs transition the MPO terminated cables to collections of LC
>>>>>> or SC connectors. If fan-outs are not present, the cabling is
>>>>>> ready to support parallel applications by using array equipment
>>>>>> cords. As far as I am aware this pre-terminated cabling approach
>>>>>> is the primary way data centers are built today, and has been in
>>>>>> practice for many years. So array terminations are commonly used
>>>>>> on single-mode cabling infrastructures. While that last statement
>>>>>> is true, it could leave a distorted impression if I also did not
>>>>>> say that virtually the entire existing infrastructure e!
>>>>>> mploys fan-outs today simply because parallel applications have
>>>>>> not been deployed in significant numbers. But migration to
>>>>>> parallel optic interfaces is a matter of removing the existing
>>>>>> fan-outs. This is what I tried to describe at the microphone
>>>>>> during November's meeting.
>>>>>>
>>>>>> Regards,
>>>>>> Paul
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Brad Booth [mailto:Brad_Booth@xxxxxxxx]
>>>>>> Sent: Wednesday, November 16, 2011 11:34 AM
>>>>>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>>>>>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>>>>>
>>>>>> Anyone have any data on distribution of parallel vs duplex volume
>>>>>> for
>>>>>> OM3/4 and OS1?
>>>>>>
>>>>>> Is most SMF is duplex (or simplex) given the alignment requirements?
>>>>>>
>>>>>> It would be nice to have a MMF version of 100G that doesn't
>>>>>> require parallel fibers, but we'd need to understand relative cost
>>>>>>differences.
>>>>>>
>>>>>> Thanks,
>>>>>> Brad
>>>>>>
>>>>>>
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Ali Ghiasi
>>>>>> [aghiasi@xxxxxxxxxxxx<mailto:aghiasi@xxxxxxxxxxxx>]
>>>>>> Sent: Wednesday, November 16, 2011 11:04 AM Central Standard Time
>>>>>> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>>>>>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>>>>>
>>>>>> Jack
>>>>>>
>>>>>> If there is another LR4 PMD out there the best starting point
>>>>>> would be 40Gbase-LR4, look at its cost structure, and build a
>>>>>> 40G/100G compatible PMD.
>>>>>>
>>>>>> We also need to understand the cost difference between parallel
>>>>>> MR4 vs
>>>>>> 40Gbase-LR4 (CWDM). The 40Gbase-LR4 cost with time could be
>>>>>> assumed identical to the new 100G MR4 PMD. Having this baseline
>>>>>> cost then we can compare its cost with 100GBase-LR4 and parallel
>>>>>> MR4. The next step is to take into account higher cable and
>>>>>> connector cost associated with parallel implementation then
>>>>>> identify at what reach it gets to parity with 100G
>>>>>> (CWDM) or
>>>>>> 100G (LAN-WDM).
>>>>>>
>>>>>> In the mean time we need to get more direct feedback from end
>>>>>> users if the parallel SMF is even an acceptable solution for
>>>>>> reaches of 500-1000 m.
>>>>>>
>>>>>> Thanks,
>>>>>> Ali
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Nov 15, 2011, at 8:41 PM, Jack Jewell wrote:
>>>>>>
>>>>>> Thanks for this input Chris.
>>>>>> I'm not "proposing" anything here, rather trying to frame the
>>>>>> challenge, so that we become better aligned in how cost-aggressive
>>>>>> we should be, which guides the technical approach. As for names,
>>>>>> "whatever works" :-) It would be nice to have a (whatever)R4, be
>>>>>> it nR4 or something else, and an english name to go with it. The
>>>>>> Structured Data Center (SDC) links you describe in your Nov2011
>>>>>> presentation are what I am referencing, except for the restriction
>>>>>> to "duplex SMF." My input is based on use of any interconnection
>>>>>> medium that provides the overall lowest-cost, lowest-power
>>>>>> solution, including e.g. parallel SMF.
>>>>>> Cost comparisons are necessary, but I agree tend to be dicey.
>>>>>> Present 10GbE costs are much better defined than projected 100GbE
>>>>>> NextGen costs, but there's no getting around having to estimate
>>>>>> NextGen costs, and specifying the comparison. Before the straw
>>>>>> poll, I got explicit clarification that "LR4" did NOT include
>>>>>> mux/demux IC's, and therefore did not refer to what is built
>>>>>> today. My assumption was a "fair" cost comparison between LR4 and
>>>>>> (let's call it)nR4 - at similar stage of development and market
>>>>>> maturity. A relevant stage is during delivery of high volumes
>>>>>> (prototype costs are of low relevance). This does NOT imply same
>>>>>> volumes. It wouldn't be fair to project ER costs based on SR or
>>>>>> copper volumes. I'm guessing these assumptions are mainstream in
>>>>>> this group. That would make the 25% cost target very aggressive,
>>>>>> and a 50% cost target probably sufficient to justify an optimized
>>>>>> solution. Power requirements are a part of the total cost of
>>>>>> ownership, and should be consider!
>>>>>> ed, but perhaps weren't.
>>>>>> The kernel of this discussion is whether to pursue "optimized
>>>>>> solutions"
>>>>>> vs "restricted solutions." LR4 was specified through great
>>>>>> scrutiny and is expected to be a very successful solution for 10km
>>>>>> reach over duplex SMF. Interoperability with LR4 is obviously
>>>>>> desirable, but would a 1km-spec'd-down version of LR4 provide
>>>>>> sufficient cost/power savings over
>>>>>> LR4 to justify a new PMD and product development? Is there another
>>>>>> duplex SMF solution that would provide sufficient cost/power
>>>>>> savings over LR4 to justify a new PMD and product development? If
>>>>>> so, why wouldn't it be essentially a 1km-spec'd-down version of
>>>>>> LR4? There is wide perception that SDC's will require costs/powers
>>>>>> much lower than are expected from LR4, so much lower that it's
>>>>>> solution is a major topic in HSSG. So far, it looks to me like an
>>>>>> optimized solution is probably warranted. But I'm not yet
>>>>>> convinced of that, and don't see consensus on the issue in the
>>>>>> group, hence the discussion.
>>>>>> Cheers, Jack
>>>>>>
>>>>>> From: Chris Cole
>>>>>> <chris.cole@xxxxxxxxxxx<mailto:chris.cole@xxxxxxxxxxx>>
>>>>>> Reply-To: Chris Cole
>>>>>> <chris.cole@xxxxxxxxxxx<mailto:chris.cole@xxxxxxxxxxx>>
>>>>>> Date: Tue, 15 Nov 2011 17:33:17 -0800
>>>>>> To:
>>>>>> <STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-100GNGO
>>>>>> PTX@L
>>>>>> I
>>>>>> S
>>>>>> T
>>>>>> SERV.IEEE.ORG>>
>>>>>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>>>>>
>>>>>> Hello Jack,
>>>>>>
>>>>>> Nice historical perspective on the new reach space.
>>>>>>
>>>>>> Do I interpret your email as proposing to call the new 150m to
>>>>>> 1000m standard 100GE-MR4? ☺
>>>>>>
>>>>>> One of the problems in using today’s 100GE-LR4 cost as a
>>>>>> comparison metric for new optics is that there is at least an
>>>>>> order of magnitude variation in the perception of what that cost
>>>>>> is. Given such a wide disparity in perception, 25% can either be
>>>>>>impressive or inadequate.
>>>>>>
>>>>>> What I had proposed as reference baselines for making comparisons
>>>>>> is 10GE-SR (VCSEL based TX), 10GE-LR (DFB laser based TX) and
>>>>>> 10GE-ER (EML based TX) bit/sec cost. This not only allows us to
>>>>>> make objective relative comparisons but also to decide if the
>>>>>> technology is suitable for wide spread adoption by using rules of
>>>>>> thumb like 10x the bandwidth (i.e. 100G) at 4x the cost (i.e. 40%
>>>>>> of 10GE-nR cost) at similar high volumes.
>>>>>>
>>>>>> Using these reference baselines, in order for the new reach space
>>>>>> optics to be compelling, they must have a cost structure that is
>>>>>> referenced to a fraction of 10GE-SR (VCSEL based) cost, NOT
>>>>>> referenced to a fraction of 10GE-LR (DFB laser based) cost.
>>>>>> Otherwise, the argument can be made that
>>>>>> 100GE-LR4 will get to a fraction of 10GE-LR cost, at similar
>>>>>> volumes, so why propose something new.
>>>>>>
>>>>>> Chris
>>>>>>
>>>>>> From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx]
>>>>>> Sent: Tuesday, November 15, 2011 3:06 PM
>>>>>> To:
>>>>>> STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-100GNGOP
>>>>>> TX@LI
>>>>>> S
>>>>>> T
>>>>>> S
>>>>>> ERV.IEEE.ORG>
>>>>>> Subject: [802.3_100GNGOPTX] Emerging new reach space
>>>>>>
>>>>>> Following last week's meetings, I think the following is relevant
>>>>>> to frame our discussions of satisfying data center needs for
>>>>>> low-cost low-power interconnections over reaches in the roughly
>>>>>>150-1000m range.
>>>>>> This is a "30,000ft view,"without getting overly specific.
>>>>>> Throughout GbE, 10GbE, 100GbE and into our discussions of 100GbE
>>>>>> NextGenOptics, there have been 3 distinct spaces, with solutions
>>>>>> optimized for each: Copper, MMF, and SMF. With increasing data
>>>>>> rates, both copper and MMF specs focused on maintaining minimal
>>>>>> cost, and their reach lengths decreased. E.g. MMF reach was up to
>>>>>> 550m in GbE, then 300m in 10GbE (even shorter reach defined
>>>>>> outside of IEEE), then 100-150m in 100GbE. MMF reach for 100GbE
>>>>>> NextGenOptics will be even shorter unless electronics like EQ or
>>>>>> FEC are included. Concurrently, MMF solutions have become
>>>>>> attractive over copper at shorter and shorter distances. Both
>>>>>> copper and MMF spaces have "literally" shrunk. In contrast, SMF
>>>>>> solutions have maintained a 10km reach (not worrying about the
>>>>>> initial 5km spec in GbE, or 40km solutions). To maintain the 10km
>>>>>> reach, SMF solutions evolved from FP lasers, to DFB lasers, to WDM
>>>>>> with cooled DFB lasers.
>>>>>> The
>>>>>> 10km solutions increasingly resemble longer-haul telecom solutions.
>>>>>>T!
>>>>>> here is an increasing cost disparity between MMF and SMF solutions.
>>>>>> This
>>>>>> is an observation, not a questioning of the reasons behind these
>>>>>> trends.
>>>>>> The increasing cost disparity between MMF and SMF solutions is
>>>>>> accompanied by rapidly-growing data center needs for links longer
>>>>>> than MMF can accommodate, at costs less than 10km SMF can
>>>>>> accommodate. This has the appearance of the emergence of a new
>>>>>> "reach space," which warrants its own optimized solution. The
>>>>>> emergence of the new reach space is the crux of this discussion.
>>>>>> Last week, a straw poll showed heavy support for "a PMD supporting
>>>>>> a 500m reach at 25% the cost of 100GBASE-LR4" (heavily favored
>>>>>> over targets of 75% or 50% the cost of 100GBASE-LR4). By heavily
>>>>>> favoring the most aggressive low-cost target, this vote further
>>>>>> supports the need for an "optimized solution" for this reach
>>>>>> space. By "optimized solution" I mean one which is free from
>>>>>> constraints, e.g. interoperability with other solutions. Though
>>>>>> interoperability is desirable, an interoperable solution is
>>>>>> unlikely to achieve the cost target. In the 3 reach spaces
>>>>>> discussed so far, there is NO interoperability between copper/MMF,
>>>>>> MMF/SMF, or copper/SMF. Copper, MMF and SMF are optimized
>>>>>> solutions. It will likely take an optimized solution to satisfy
>>>>>>this "mid-reach"
>>>>>> space
>>>>>> at the desired costs. To repeat: This has the appearance of the
>>>>>> emergence of a new "reach space," which warrants its own optimized
>>>>>> solution.
>>>>>> Since
>>>>>> the reach target lies between "short reach" and "long reach," "mid!
>>>>>> reach" is a reasonable term
>>>>>> Without discussing specific technical solutions, it is noteworthy
>>>>>> that all 4 technical presentations last week for this "mid-reach"
>>>>>> space involved parallel SMF, which would not interoperate with
>>>>>> either 100GBASE-LR4, MMF, or copper. They would be optimized
>>>>>> solutions, and interest in their further work received the highest
>>>>>> support in straw polls. Given the high-density environment of
>>>>>> datacenters, a solution for the mid-reach space would have most
>>>>>> impact if its operating power was sufficiently low to be
>>>>>> implemented in a form factor compatible with MMF and copper
>>>>>> sockets.
>>>>>> Cheers, Jack
>>
>
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