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RE: Equalization and benefits of Parallel Optics.


After a lot of thought from a customer implementation viewpoint, that is 
conclusion that I have come to.

Thank you,
Roy Bynum

At 04:29 PM 7/31/00 -0600, Chris Simoneaux wrote:

>Nice piece of info.  It is worthwhile to finally get an installer/end user
>perspective of the environment that 10GbE will exist in.  If one believes
>your analysis (and I haven't seen any contradictions), then it would seem
>quite reasonable to expect a PMD objective which covers the 2~20m
>space.....i.e 66% of the initial market.
>Would you agree?
>-----Original Message-----
>From: Roy Bynum []
>Sent: Monday, July 31, 2000 10:01 AM
>To: Chris Diminico;
>Subject: Re: Equalization and benefits of Parallel Optics.
>You had sent me a request for information similar to this.  I have not been
>very busy with other things so could not respond properly.  Hopefully this
>will also help and add weight to our, the customers, concerns.
>I had a meeting with a major technology consumer last week.  I will not
>state any names, but you can guess who.  They were very interested in 10GbE
>early on as part of their data facility overbuild plans.  It is in this
>context that I want to make these comments.
>As part of my role in the design and implementation of advanced
>architecture data networks, I have been involved with the design and
>implementation of data facilities for about ten years.  This e-mail is a
>simple overview of how these are designed and implemented.
>Large data facilities take a long time to plan and build.  As such the
>initial design and implementation is based on existing mature
>technology.  The initial construction within the data facility is grouped
>in a common area, generally one end of room. If the routers are located in
>the same room as the servers, they will generally be along a wall in the
>data room.  The servers and data storage systems are put in the room next
>to the area where the routers were installed.  Data switches which
>aggregate the traffic and manage the server traffic flow are sometimes
>located with the routers, and sometimes located with the servers.  Where
>there is planed router growth, the switches are installed adjacent to the
>servers.  From time to time, the routers are located in a different room,
>with longer reach connections between the aggregation data switches and the
>In most cases, the rows of equipment are at most about 20 equipment
>racks/cabinets long.  For 24in racks that is about 40 feet (12.2m), for
>19in racks that is about 32 feet (9.75m).  Most of the time data switches
>will be in the same row as the servers, to reduce the amount of cable trays
>and cable handling between rows.  Often the aggregation data switches will
>be in the middle of the row to reduce the distance of the interconnect
>cabling.  The row to row distance is about 8 feet (2.5m).  Even with the
>riser from the bottom of one rack/cabinet at one end of the row to the
>bottom of the rack/cabinet at the other end of adjacent rows, the
>interconnections are less than 20m.
>For new technology overbuilds of existing data rooms, the new technology
>systems are grouped together in a different area of the data room than the
>mature technology.  The data switches to support the new technology systems
>are co-located in the same row with those systems.  In these situation, the
>vast majority of the new technology interconnections are within the row of
>the new technology overbuild, less than 20m.  By some estimates, data rooms
>designed specifically around 10GbE will be at least two years away.  Given
>that the initial deployment of 10GbE will be in new technology overbuilds
>of these data rooms, it is very important that the ability to understand
>and use the same construction techniques and technologies, such as the type
>of fiber and fiber management systems.
>It is a personal estimation on my part that the high capacity data switches
>will be at about 500+ Gb aggregate bandwidth per bay/cabinet by about
>2002.  As such, they will handle a total of 50 10GbE links.  With a limit
>of 19 racks for servers, even at single non-redundant 10Gb link each that
>is 19 links.  For servers with redundant links that is 38 ports, or about
>380Gb aggregate bandwidth which would exceed the ability of the data switch
>interconnect with any outside communications systems.  In the case of
>exceeding the aggregate bandwidth of any one switch, multiple switches are
>interconnected.  These switches could be located next to each other or, as
>is more likely, at equal distances long the row of servers. As more and
>more and more servers come on line, the number of supporting data switches
>increases along with the interconnections between the data switches.   In
>this situation, the implementation of the interconnections will be about
>1/3 (33%) of the data switch ports will be connected to the supported
>servers/storage systems; 1/3 (33%) of the data switch ports will be
>interconnections between the aggregation data switches; and 1/3 (33%) of
>the ports on the aggregation data switches will be to outside
>communications systems.  From this simple model it is easy to see that
>potentially 66% of the initial 10GbE links will be less than 20m.
>Thank you,
>Roy Bynum
>At 05:45 PM 7/28/00 -0400, Chris Diminico wrote:
> >
> >Corey,
> >
> >A personal thanks for the invaluable customer input. I believe that if we
> >had more customers
> >coming forward with their detailed requirements it would help break the
> >current stalemate in the PMD
> >selections. This is the type of debate that I hoped to stimulate in
> >proposing that we should
> >re-address the objectives of the PMD s; we need to clearly resolve any
> >ambiguity in the
> >objective statements in regards to application-space media-distances and
> >the usage of the word
> >"installed" to represent MMF fiber performance.
> >
> >As a supplier of Internet infrastructure product for Ethernet customer
> >applications,
> >I hear requests such as yours each day. I ll paraphrase in bullets here,
> >borrowing from your e-mail.
> >
> >----My reason for wanting MMF (a 10G interface over MMF) is primarily cost
> >simplicity, and
> >     compatibility with my current applications (technology and distances).
> >----Cost - overall cost for the total installation.
> >+++Labor LAN installers familiar with multimode terminations produce
> >higher yields per unit time
> >                  versus single mode.
> >+++Materials: Connectors, tools, patch cables, test equipment, Laser/LED
> >transceivers, etc...
> >
> >Other customers of 10 Gb/s Ethernet addressing the reflector and the task
> >group have
> >voiced strong support for the inclusion of a low-cost short-reach
> >multimode fiber objective
> >even if it included the use of higher bandwidth MMF. The task group
> >responded to these
> >clearly stated customer requirements by including in the current set of
> >objectives a physical
> >layer specification for operation over 300 m of MMF. Omission of the word
> >"installed" was to
> >implicitly allow for the new higher bandwidth MMF fiber. The usage of the
> >word "installed" in the
> >100 meter objective was to identify the MMF with the MMF currently
> >specified in 802.3z.
> >
> >In order to clearly identify the current implicit differences in the MMF
> >objective fiber types,
> >
> >I offer the following definitions.
> >
> >+++++Installed MMF MMF as specified in 802.3z.
> >+++++MMF Either installed MMF or the Next Generation MMF fiber
> >currently proposed in both TIA and ISO. The development for these
> >specification
> >was supported in a Liaison letter issued from IEEE.
> >
> >A low-cost serial 850 nm PMD option coupled with the benefits of the
> >higher bandwidth
> >300 meter multimode fiber solution will addresses your requirements for
> >cost, simplicity, and compatibility
> >with your current Ethernet (10 Mb/s-100 Mb/s-1 Gb/s) distances and for the
> >10 Gb/s Ethernet
> >distances. Additionally, the new MMF coupled with the right PMD would
> >allow for next generation
> >40 Gb/s Ethernet applications.
> >
> >The impact of media selection on technology deployment can be severe.
> >The debate over driving single mode versus higher performance multimode for
> >new "in the building" LAN installations has the same flavor as coax versus
> >twisted-pair.
> >Before coming to CDT, I had worked at Digital Equipment Corporation for
> >almost 20 years.
> >DEC lost the Ethernet repeater business (coax) primarily due to its
> >slowness in responding
> >to the customer requirements for Ethernet over twisted-pair. DEC said,
> >"coax is technology
> >proof and will meet all of your long term application needs", the customer
> >said, "but my
> >reason for wanting twisted-pair is overall cost (installation, testing,
> >materials), simplicity, and
> >compatibility with my current applications (technology and distances). The
> >rest is history.
> >
> >
> >Chris Di Minico
> >Cable Design Technologies (CDT) Corporation
> >Director of Network Systems Technology
> >Phone: 800-422-9961 ext:333
> >e-mail: <>
> >
> >
> >>----- Original Message -----
> >>From: <>McCormick, Corey
> >>To: <>
> >>Sent: Thursday, July 27, 2000 12:31 AM
> >>Subject: RE: Equalization and benefits of Parallel Optics.
> >>
> >>I also may be a bit confused.  From a business perspective I have this
> >>
> >>My reason for wanting a 10G interface over MMF is primarily cost and
> >>simplicity.  Most of the servers I have installed are within 100M and
> >>most of the core and distribution switches are as well.  If there is a
> >>low-cost way to use some new-fangled media, then fine, but it seems to me
> >>that improving ASIC technologies and economies of scale are the primary
> >>downward factors in interface technologies.
> >>
> >>If the MMF limit is 100M or less then the pain incurred for me installing
> >>new MMF is relatively minor, as the distance is not that large.  This
> >>means the number of labor-intensive obstacles encountered will be
> >>small.  It is work and cost to be sure, but if the runs were for
> >>200-500M+ then the labor costs would be *much* higher.  However, I
> >>believe the costs for the tooling, cables, certification gear and
> >>connectors will increase if we choose some new radically different
> >>technology as the only choice.  In our experience the SFF connectors are
> >>not significantly less in overall cost.  (there are exceptions, but for
> >>the majority of them the costs are quite similar to ST/SC)  We still have
> >>*much* more difficulty with the SFF installations due to primarily lack
> >>of available cables, field termination components, and conversion
> >>cables.  Also, there is the major problem of field Zip<->Dual fiber MM
> >>adaptation to our installed ST/SC infrastructure (yuk!).
> >>
> >>I really do not care which technology is selected/specified, but for the
> >>short-haul standard my primary goal is lowest overall cost for the total
> >>installation.  (Labor, connectors, tools, patch cables, test equipment,
> >>Laser/LED transceivers, etc...)  I care very little about which form
> >>factor, mostly the cost and ease of use.
> >>
> >>If such relatively simple Net things as the broken 10/100 Autoneg Phy and
> >>LX mode adaptation/conditioning cables are such a problem in the wide
> >>acceptance of new technologies, then it seems like the KISS principle
> >>should be a strong factor.  I do not care how complicated it is
> >>internally, but it needs to be simple for the end user.
> >>
> >>I also seems to remember that the goal was 3X the cost of 1G.  If the
> >>cable length limits are going to be <100M, then the
> >>real-world-end-user-makes-the-comparison will be with 1000Base-TX copper,
> >>not SX.  This might make it much more difficult to complete the 3X cost
> >>target unless there are *significant* savings in the
> >>Phy/Xceiver/cable/connector/tools area.
> >>
> >>My engineering hat does not always agree with this, but then it is
> >>business that pays the bills.
> >>
> >>What do you good folks think?
> >>
> >>Corey McCormick
> >>CITGO Petroleum
> >>
> >>  -----Original Message-----
> >>From:   Booth, Bradley
> >>[<>]
> >>Sent:   Wednesday, July 26, 2000 8:30 PM
> >>To:
> >>Subject:        RE: Equalization and benefits of Parallel Optics.
> >>
> >>I have one question:
> >>
> >>Which of our distance objectives is satisfied with parallel fiber and
> >>parallel optics?
> >>
> >>It has been my interpretation that when we talked about 100m of installed
> >>base of MMF, that we were referring to the MMF fiber currently available
> >>use by 802.3z.  Parallel optics does not operate over this installed base.
> >>
> >>Or am I missing the point here?
> >>
> >>Cheers,
> >>Brad
> >>
> >>         -----Original Message-----
> >>         From:   ghiasi []
> >>         Sent:   Tuesday, July 25, 2000 8:32 PM
> >>         To:;;
> >>
> >>         Cc:
> >>         Subject:        RE: Equalization and benefits of Parallel Optics.
> >>
> >>         Sharam
> >>
> >>         > From: "Hakimi, Sharam (Sharam)" <>
> >>         > To:, "''"
> >>         <>
> >>         > Subject: RE: Equalization and benefits of Parallel Optics.
> >>         > Date: Tue, 25 Jul 2000 21:04:49 -0400
> >>         > MIME-Version: 1.0
> >>         > X-Resent-To: Multiple Recipients
> >><>
> >>         > X-Listname: stds-802-3-hssg
> >>         > X-Info: [Un]Subscribe requests to
> >>         > X-Moderator-Address:
> >>         >
> >>         >
> >>         > Although parallel fiber is technically an easier solution, the
> >>major reason
> >>         > for support of 850nm has been to consider the installed base,
> >>cost. If
> >>         > users have to pull new fiber, IMHO, parallel fiber would not
> >> be on
> >>top of
> >>         > the list and most of installed base is single fiber.
> >>
> >>         I did not suggest to pull any new fiber.  Limit the shortwave
> >>variant
> >>         including parallel optics to the data center with 100 m radius.
> >>
> >>         Thanks,
> >>
> >>         Ali Ghiasi
> >>         Sun Microsytems
> >>
> >>         >
> >>         > Sharam Hakimi
> >>         > Lucent Technologies
> >>         >
> >>