RE: PMDs and Customer requirements
Chris,
The 100m objective is a pretty standard based on multiple surveys over the
years for networking installations. At 100m, you can satisfy something like
95+ per cent of the horizontal runs, wiring closets, etc. Most structured
wiring standards have, therefore, specified this distance as maximum, so it
has become self fulfilling, i.e. installers specify all new horizontal runs
to be less than 100m, wiring closets are placed in order to ensure the 100m
max, etc.
The "installed base" part is relevant because of the reasons Bruce has
elaborated.
I believe the 300m is for campus environments, building to building, etc.
Walt
> -----Original Message-----
> From: Chris Simoneaux [mailto:csimoneaux@xxxxxxxxxxxxx]
> Sent: Tuesday, May 30, 2000 7:47 PM
> To: 'Bruce Tolley'; Walter Thirion; '802.3ae'
> Subject: RE: PMDs and Customer requirements
>
>
> Bruce,
>
> My concern here is that we are letting the needs of the few
> drive the needs
> of the many...so to speak. As an equipment vendor, you must
> support any
> application that the customer brings to you. That's a fact
> we all would
> agree with. However, I disagree with basing the success of
> 10GbE on how
> well it supports the minority applications.
>
> Customers are typically adverse to "forklift upgrades". But
> in the end,
> it's a matter of economics. And the cost vs. profit of the
> upgrade is the
> determining factor. If most of the user's links are shorter than 100m
> (probably much shorter), then the approach to the system upgrade will
> usually be based on the short distance link and expand into
> the lower volume
> longer distance links, not the other way around.
>
> Embedded in this PMD selection process is the 850nm serial
> solution. It
> clearly offers a solution for the 300m objective. It also
> offers added
> value of lowest cost, simplistic interconnections for all MM
> fibers up to
> 28m and most 50um MM fibers up to 86 meters. If technology
> proliferation is
> important, then 850nm serial should be a choice as it has
> several vendors
> that are doing actual link testing. And one that is actively
> demo'ing in
> the public forum. Ask that of any WDM solution. With all of
> it's benefits,
> why would the group not include the 850nm solution? Maybe
> someone can help
> me understand that.
>
> Also, I must respectfully ask for someone out there to inform
> me why the
> "100m over installed base", objective was chosen. Why not
> 50m? or 150m?
> Were there any scientific data or surveys used? Don't
> misinterpret, this is
> not a "knock" on the 802.3ae process. It's merely a question
> that's been
> bugging me for a while now.
>
> Finally, I would suggest we base our PMD solution set
> opinions on straw
> polls where all participants have an opportunity to vote.
> Informal straw
> polls can be misleading. Each subgroup within the 802.3ae
> seems to have an
> opinion on the PMD issue. However, we should not forget
> about the user
> community. The only user that stood up and voiced an opinion (that I
> remember) during the Ottawa meeting was MCI/Worldcom, and I
> believe they
> stood in support of 850nm serial. Correct me if I'm wrong.
>
> Chris
>
> -----Original Message-----
> From: Bruce Tolley [mailto:btolley@xxxxxxxxx]
> Sent: Tuesday, May 30, 2000 9:49 AM
> To: Walter Thirion; '802.3ae'
> Subject: PMDs and Customer requirements
>
>
>
> Walter:
>
> I have to reject the 2nd most popular set because it abandons
> the installed
> base of customers using their installed 62.5 nm 160 and 200
> MHz*km fiber.
>
> o Buildings will not move because of 10 GbE
>
> o The cabling infrastructure will not change overnight
> because of 10 GbE
>
> o Customers have a requirement to run 10 GbE on the same
> fiber links they
> run 1 GbE today
>
> o Customers have a requirement to use 10 GbE in building backbone
> applications on their installed fiber to distances of 200 to
> 300 meters.
>
> There is only one PMD proposal that runs on the installed
> fiber at building
> backbone distances: the 4 lambda 1300 nm WWDM proposal. If we do not
> support the installed base, it will stall the market acceptance of 10
> GbE. Customers resist forklift upgrades.
>
> At the meeting in York I felt that the study group basically
> abandoned the
> installed base of customer by deleting the word "installed"
> out of the 300
> meter goal. We have to build a standard that supports the
> installed base
> of building backbones. There is no good reason to exclude the
> one proposal
> that supports this market segment.
>
> I have not hung up on the number of 3 PMDs but we have to
> have the one that
> supports the installed base of fiber out to 300 meters.
>
>
> Bruce Tolley
> Enterprise Line of Business
> Cisco Systems
>
>
>
> At 12:58 PM 5/28/00 -0500, Walter Thirion wrote:
>
> >First of all, thanks to everybody that presented PMD
> proposals at the last
> >meeting. I've sent my presentation to David Law, so it
> should be available
> >on the web site in the next couple of days.
> >
> >In listening to the discussion after my presentation and
> then going around
> >and talking to people, it feels to me like we're starting to
> converge. Not
> >there, yet, but making progress.
> >
> >The equipment manufacturers made it pretty clear they would
> like to see no
> >more than 3 PMDs in the standard. The PMD vendors have some
> concern that
> >using only 3 PMDs may sub-optimize certain objectives,
> however, they could
> >support the 3 PMD position if it is made clear which 3 PMDs
> the equipment
> >oems want.
> >
> >Based on an informal straw poll and anecdotal evidence, my
> opinion is the
> >first choice would be the set:
> >________________
> >850 nm WWDM
> >1310 nm WWDM
> >1550 nm Serial
> >________________
> >
> >If that set isn't feasible, then the 2nd most popular choice is:
> >________________
> >850 nm WWDM
> >1310 nm Serial
> >1550 nm Serial
> >________________
> >
> >Thoughts, feedback?
> >
> >Walt
> >___________________
> >Walter Thirion
> >Chair, IEEE 802.3ae PMD Sub-Task Force
> >301 Congress Ave.
> >Suite 2050
> >Austin, Texas 78701
> >Voice: 512-236-6951
> >Fax: 512-236-6959
> >wthirion@xxxxxxxxxxxx
> >___________________
> >
>