Re: Equalization and benefits of Parallel Optics.
I agree with Jaime that a simple XAUI extender with appropriate cables and
connectors could provide the lowest cost solutions for the 2~20m range. Such a
solution is being pursued in the Fiber Channel T11.2 committee.
Bharat Tailor
Gennum Corporation
"Kardontchik.Jaime" wrote:
> Chris Simoneaux wrote on July 31:
>
> > Roy,
> > 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?
> >
>
> I wonder what would be cheaper for a few meters distance:
> an optical link (laser+fiber+photodetector+TIA) or a plain XAUI
> extender using cat-6 unshielded twisted-pair Copper cable.
> Notice that a XAUI extender uses separate traces (or wire)
> for transmitter and receiver. Hence, we do not have to deal
> with "echo cancellers", so these Copper transceivers should
> be doable.
>
> Jaime E. Kardontchik
> Micro Linear
> San Jose, CA 95131
>
> >
> >
> >
> > -----Original Message-----
> > From: Roy Bynum [mailto:rabynum@xxxxxxxxxxxxxx]
> > Sent: Monday, July 31, 2000 10:01 AM
> > To: Chris Diminico; stds-802-3-hssg@xxxxxxxx
> > Subject: Re: Equalization and benefits of Parallel Optics.
> >
> > Chris,
> >
> > 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
> > routers.
> >
> > 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
> > specifications
> > >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: <mailto:cd@xxxxxxxxxxxxxx>cd@xxxxxxxxxxxxxx
> > >
> > >
> > >>----- Original Message -----
> > >>From: <mailto:Corey@xxxxxxxxx>McCormick, Corey
> > >>To: <mailto:stds-802-3-hssg@xxxxxxxx>stds-802-3-hssg@xxxxxxxx
> > >>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
> > view.
> > >>
> > >>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
> > >>[<mailto:bradley.booth@xxxxxxxxx>mailto:bradley.booth@xxxxxxxxx]
> > >>Sent: Wednesday, July 26, 2000 8:30 PM
> > >>To: stds-802-3-hssg@xxxxxxxx
> > >>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
> > for
> > >>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 [SMTP:Ali.Ghiasi@xxxxxxxxxxx]
> > >> Sent: Tuesday, July 25, 2000 8:32 PM
> > >> To: stds-802-3-hssg@xxxxxxxx; Daljeet_Mundae@xxxxxxxxx;
> > >>hakimi@xxxxxxxxxx
> > >> Cc: Ali.Ghiasi@xxxxxxxxxxx
> > >> Subject: RE: Equalization and benefits of Parallel Optics.
> > >>
> > >> Sharam
> > >>
> > >> > From: "Hakimi, Sharam (Sharam)" <hakimi@xxxxxxxxxx>
> > >> > To: stds-802-3-hssg@xxxxxxxx, "'Daljeet_Mundae@xxxxxxxxx'"
> > >> <Daljeet_Mundae@xxxxxxxxx>
> > >> > 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
> > >><stds-802-3-hssg@xxxxxxxxxxxxxxxxxx>
> > >> > X-Listname: stds-802-3-hssg
> > >> > X-Info: [Un]Subscribe requests to majordomo@xxxxxxxxxxxxxxxxxx
> > >> > X-Moderator-Address:
> > stds-802-3-hssg-approval@xxxxxxxxxxxxxxxxxx
> > >> >
> > >> >
> > >> > Although parallel fiber is technically an easier solution, the
> > >>major reason
> > >> > for support of 850nm has been to consider the installed base,
> > and
> > >>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
> > >> >
> > >>
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