RE: Short haul PMDs
During the past 15 years and through all of 802.3 distance Objectives, 100
meters has been the minimum and essentially the trademark of IEEE 802.3.
There has always been discussions that if the distance is reduced we can
provide less expensive PHYs, but the cost difference never justified
development of these PHYs . Providing 100 meter solutions does not prevent
anyone from using a 10, 20, 30 or other length cables as their needs
require. However, if time has come that the cost difference between a 100
meter solution and something less will justify such development then we
could look at it later, but changing the objectives at this time is a BAD
idea in my opinion.
> From: Satish M.[SMTP:satish@xxxxxxxxxxxxxxxx]
> Reply To: satish@xxxxxxxxxxxxxxxx
> Sent: Wednesday, August 02, 2000 11:54 AM
> To: rtaborek@xxxxxxxxxxxxx
> Cc: HSSG
> Subject: Re: Short haul PMDs
> I am also interested in short haul solution, primarily within Data
> centers and enterprises. My main area of interest is for ethernet
> based SANs.
> Rich Taborek wrote:
> > Ladies and Gentlemen,
> > My best recollection of straw polls by Jonathan, our chair, was that the
> > user community was very poorly represented at meetings. Recently, we
> > have heard from two members of the Ethernet user community, representing
> > very high volume Ethernet equipment users, that short haul PMDs are key.
> > I know from others related standards bodies and industry associations
> > representing SANs and clustered networks, sometimes referred to as
> > System Area Networks, that the percentage of short haul links (<100 m)
> > is significantly more than that encountered in LAN environments.
> > Throwing typically short haul MAN/WAN access links into the fray, I'm
> > having a hard time swallowing both the current HSSG distance/cable plant
> > objectives and PMD solution set. This is especially true in light of a
> > the last, but not least PAR criteria of Economic Feasibility.
> > Ethernet users are demanding low-cost short-haul solutions. A small
> > number of well defined and simple candidate solutions have been
> > proposed. I suggest going with those solutions. If it takes adding a
> > short-haul objective (<100 m) to get off the dime and allow the Task
> > Force to further develop PMD solutions for the multimode fiber
> > objectives, let's do it! I don't believe that the user community would
> > settle for proprietary short haul solutions for well over half of their
> > connections.
> > It would help a great deal to hear from other users.
> > Best Regards,
> > Rich
> > --
> > > "McCormick, Corey" wrote:
> > >
> > > Our experience is still very similar. Last weekend we just cut our
> > > last refinery from FDDI/Ethernet to GigE switches and again more than
> > > half of the GigE ports are <25m and most of those are either 2-4m or
> > > 10-15m. These short runs all used new cables with the correct ends so
> > > there would be no couplers or splices. They are all SC or MT-RJ
> > > (spec'd to get port density in the switches). The longer installed
> > > links are 300m - 1Km and all are using 9 year old FDDI-spec fiber on
> > > ST connectors. There are only ~10% LX and the rest are SX. We would
> > > have used copper for the shorter links (cables that stay inside one
> > > building and are <90M) had the cables, NICs, switch ports and GBICs
> > > all been available at the time of the order/installation. I do not
> > > know about others, but our short runs far outnumber long ones.
> > >
> > > Also it might be noted that petrochemical refineries are among the
> > > larger manufacturing complexes in the world. They are large very
> > > 2-dimensional installations and are usually measured in Km, not feet.
> > > While we have some SM applications, 95+% are MM and the majority of
> > > the ports will be hosts. I can only speculate that this will follow
> > > as we move to 10G. Our physical architecture seems to stay about the
> > > same regardless of the technology. Ethernet was replaced by FDDI,
> > > which was replaced by ATM or GigE, which I believe will be replaced by
> > > 10GE in the same pattern. As this was our last location to convert,
> > > we have now done them all in a similar fashion and they were designed
> > > and implemented by three different teams. (admittedly with some
> > > cross-pollinated influence)
> > >
> > > Gates, Kroc, Walton all believe(d) that volume wins and I my
> > > experience leaves me not in a position to argue. Which is better SCSI
> > > or IDE/ATAPI? I believe SCSI to be the more scaleable, manageable and
> > > extensible design, but ATAPI wins volume and thus cost by a huge
> > > margin. I do not like the KISS principle sometimes, but it is more
> > > often than not the correct one. So long as there can be modular
> > > ports (a.k.a. GBICs), then the actual port technology matters little
> > > to the switch/NIC vendors, but when there can be a low-cost solution
> > > integrated everywhere, even with its limitations, I think that will be
> > > the most successful.
> > >
> > > So, to improve the chances for a successful 10G implementation, it
> > > seems to me that the short solution needs to be Good, Fast and Cheap.
> > > The longer runs are varied in requirements and not as cost sensitive
> > > since we need many fewer of them.
> > >
> > > Just more experience,
> > >
> > > Corey McCormick
> > > CITGO Petroleum
> > >
> > > -----Original Message-----
> > > From: Roy Bynum [mailto:rabynum@xxxxxxxxxxxxxx]
> > > Sent: Tuesday, August 01, 2000 2:00 PM
> > > To: Chris Simoneaux; stds-802-3-hssg@xxxxxxxx
> > > Subject: RE: Equalization and benefits of Parallel Optics.
> > >
> > > Chris,
> > >
> > > 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:
> > >
> > > >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?
> > > >
> > > >Regards,
> > > >Chris
> > -------------------------------------------------------
> > Richard Taborek Sr. Phone: 408-845-6102
> > Chief Technology Officer Cell: 408-832-3957
> > nSerial Corporation Fax: 408-845-6114
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> > Santa Clara, CA 95054 http://www.nSerial.com
> Satish Mali
> http://www.TrainingCity.com -> Train to success