Re: [802.3_100GNGOPTX] Emerging new reach space
Paul
I actually recall input from hssg days where such reaches were discussed for data center hotels, large multifloor buildings in cities.
Don't remember file off top of my head but I do remember the data point.
John
Sent from my iPhone
On Nov 19, 2011, at 10:56 AM, "Kolesar, Paul" <PKOLESAR@xxxxxxxxxxxxx> wrote:
> Jeff,
> I cannot imagine a data center that has 2,000m runs within a building. Such data centers must actually be multiple buildings, perhaps in a campus or office park, similar to the central offices that have driven 2km into existing specs. Once we step outside the confines of a single building we are on a rather slippery slope towards nebulous boundary conditions. Where do campus channels end and cross-town channels begin? I am not saying we should ignore these inputs, but for this exercise we really need to judge the merits of proposals based on channel-coverage-vs-cost trade-off space rather than a particular reach at the outskirts of consideration. So please quantify the frequency distribution of channel lengths that you gather to permit analysis of the type we need.
>
> Paul
>
>
> -----Original Message-----
> From: Jeffery Maki [mailto:jmaki@xxxxxxxxxxx]
> Sent: Friday, November 18, 2011 4:24 PM
> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>
> All,
>
> I am gathering data that is defensible. I'm seeing that some datacenters need reach extension to 2,000 meters. I have not gotten acceptance to using parallel SMF for even 500 meters. Parallel MMF is similarly not acceptable. I see acceptance that 100GBASE-LR4 can be brought to low cost in CFP4/QSFP-type implementations. Our efforts in relation to a cost optimized standard for -nR4 needs to be made with the realization that we are bookended by 100GBASE-SR4 QSFP/CFP4 and 100GBASE-LR4 QSFP/CFP4. Of course, if -nR4 can be lower cost than 100GBASE-SR4, then that would be very important to capture.
>
> An open question: Is there no cost to remove from the receiver? I see presentations focused on the transmitter but none on the receiver.
>
> Jeff
>
> ....................................
> Jeffery J. Maki, Ph.D.
> Distinguished Engineer, Optical
> Juniper Networks
>
>
> -----Original Message-----
> From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx]
> Sent: Friday, November 18, 2011 12:46 PM
> To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>
> I threw out 2km to err on the high side, to invite discussion - glad to
> see it, and I'd prefer to target something shorter!
> While my impression is that IDCs don't want parallel fiber, many of you
> have been far more in touch with them than me. If all we come up with for
> a duplex SMF solution comes at similar cost/power to LR4, I don't know
> if/how they will respond. I'm looking at duplex SMF solutions much harder
> than I was at the outset of this discussion.
> Cheers, Jack
>
>
> On 11/18/11 1:25 PM, "Chris Cole" <chris.cole@xxxxxxxxxxx> wrote:
>
>> Ali,
>>
>> Very well put. I had actually started proposing 600m as the max reach
>> objective earlier this year for the reasons you outline, for example at
>> the EA TEF.
>>
>> However, in a number of conversations with end users, I was persuaded
>> that 800m or even 1000m would totally future proof a standard which will
>> be with us for the next decade.
>>
>> That's why my proposal for the 100GE-nR4 objective is "minimum reach of
>> 1km".
>>
>> Chris
>>
>> -----Original Message-----
>> From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxx]
>> Sent: Friday, November 18, 2011 12:21 PM
>> To: Chris Cole; Jack Jewell
>> Cc: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
>> Subject: Re: [802.3_100GNGOPTX] Emerging new reach space
>>
>> Chris/Jack
>>
>> Looking at the link Chris send on 10x10 MSA paper from Bikash and Vijay
>> from Google are consistent with reach I showed
>> from my study of the major IDCs in the us. The 10x10 MSA paper largest
>> data center was 400000 sq-ft in the my study I estimated
>> the largest IDC in the us is now1000,000 sq-ft. In my study I only
>> assume square building where the 10x10 MSA also considered
>> rectangular building. I reported the longest reach based on square
>> building would about 600 m but if we assume rectangular building
>> then max reach would be 700 m, since we don't the actually know the
>> implementation of these IDCs, it is very likely some of these large
>> building are partitioned with longest link being shorter.
>> http://www.ieee802.org/3/100GNGOPTX/public/sept11/ghiasi_01_a_0911_NG100GO
>> PTX.pdf
>>
>> We should focus on the PMD that will deliver the cost, size, and power
>> with min reach of 600 m which is more than sufficient for IDC
>> applications.
>> If it happens we could do 2 km with no penalty then great but lets not
>> set our objective on 2 km.
>>
>> I also agree with Jack statement that duplex SMF is highly desired and is
>> consistent with inputs I have received, obviously if we can't come up
>> with any duplex PMD which is better than current 100Gbase-LR4 then
>> parallel SMF still could fill a gap.
>>
>> Thanks,
>> Ali
>>
>>
>> On Nov 18, 2011, at 11:12 AM, Chris Cole wrote:
>>
>>> 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-802-3-100GNGOPTX
>>>>>>> @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-802-3-100GNGOPTX@
>>>>>>> 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
>>>
>>