RE: PMD discussion
Paul,
By VSR I mean Very Short Reach. If we
take a moment to define it, I would say
it means those PMDs which do not satisfy
the primary distance objectives of 802.3
without some modifications to those stated
objectives.
This might suggest to you the need to modify
the objectives of the 802.3 committee. I would
consider this an option, however there are many
who would not.
VSR is a term being used loosely by the OEMs which
do not want the burden of having to support a
panoply of PMDs. Their direction has clearly been
to eliminate those which support the fewest of the
objective criteria. It is a little obvious this cuts
preferentially at the PMDs with the shortest distance
capability.
In this case, the 10GEA vote in support of 1550nm serial,
1310 serial, and 1310 WDM could be considered evidence.
Regards,
Pat Gilliland
patgil@xxxxxxxxxxx
---------------------------------------------------------
At 12:34 PM 6/2/00 -0400, you wrote:
>
>Pat,
>I am unclear as to what is meant by VSR. 802.3ae has two short reach
>objectives, 100 and 300 m. In your view, is VSR space not covered by these?
>Or is VSR sub-100m to you? Either way, I don't see the point of the
>discussion unless it is aimed at changing the objectives.
>Paul
> ----------
> From: Patrick Gilliland [SMTP:pgilliland@xxxxxxxxxxx]
> Sent: Thursday, June 01, 2000 9:34 PM
> To: stds-802-3-hssg@xxxxxxxx
> Subject: RE: PMD discussion
>
>
> Paul,
>
> Brad is suggesting, among other things, the VSR
> solutions such as 850nm might be best addressed
> in a different standard.
>
> I believe Rich Taborek has suggested the same and
> is soliciting proposals for the Fibre Channel PMD
> working group. Probably the natural place for this
> work might be a different forum. Otherwise, we must
> ask the entire membership to reexamine the objectives.
>
> I see no future in delaying the standard by maintaining
> an 850nm voting block. If the membership does not want
> to standardize VSR applications within 802.3, let's take
> it to a different forum where it is of primary interest.
>
> Regards,
>
> Pat Gilliland
> patgil@xxxxxxxxxxx
>
> --------------------------------------------------------
>
>
> At 06:17 PM 6/1/00 -0400, you wrote:
> >
> >Brad,
> >
> >There are no PMDs in the set of 5 that do not meet at least one of
>the
> >objectives. As far as the 850 nm serial PMD, I believe I made a
>strong case
> >at the May interim as to why it also broadly meets the criteria.
>80% of the
> >market for 10GbE will be under 300 m. A solution optimized for this
>large a
> >portion of the market has broad market application regardless of
>the number
> >of distance objectives it covers.
> >
> >To your point on a small subset getting 100% majority, the
>indication of the
> >straw poll from the May interim is that down selecting below 5 PMDs
>this is
> >going in the wrong direction to achieve consensus. The poll
>indicated that
> >the 5 PMD set was favored by roughly 2 to 1 compared to the closest
> >alternative of 3 PMDs. Further, I believe that the 3 PMDs are not
>the same 3
> >among the supporters of that choice, which subdivides the support.
>From my
> >perspective an inclusive approach will work better than an
>exclusive
> >approach in getting to consensus. In an inclusive approach you get
>the PMDs
> >you prefer, while others also get the PMDs they prefer. If you
>really
> >believe the market will be best served by some subset of the PMDs,
>you are
> >free to use only those.
> >
> >Regards,
> >Paul Kolesar
> >
> >
> > ----------
> > From: Booth, Bradley [SMTP:bradley.booth@xxxxxxxxx]
> > Sent: Thursday, June 01, 2000 5:19 PM
> > To: '802.3ae'
> > Subject: RE: PMD discussion
> >
> >
> > Paul,
> >
> > You touched on a key point. To quote you, "The norm is
>likely a
> >choice
> > between a small subset that is targeted for their needs." I
>see
> >this as
> > applying directly to what we need to work on. If there is
>something
> > available from another standards body (i.e. VSR VCSELs),
>then I
> >would prefer
> > to leave that effort in that standards body especially if it
>doesn't
> >broadly
> > satisfy our criteria. I think there is a small subset that
>the IEEE
> >needs
> > to standardize that we (I'm talking 100% majority) believe
>we should
> >focus
> > our effort on to meet our objectives while providing a small
>subset
> >to
> > satisfy our customer's needs.
> >
> > Cheers,
> > Brad
> >
> > -----Original Message-----
> > From: Kolesar, Paul F (Paul)
> >[mailto:pkolesar@xxxxxxxxxx]
> > Sent: Thursday, June 01, 2000 4:06 PM
> > To: '802.3ae'; 'Booth, Bradley'
> > Subject: RE: PMD discussion
> >
> > Brad,
> >
> > 802.3z not only supported the installed base
>of 62.5
> >um
> > fiber (which has two
> > bandwidth grades), but also included 50 um
>fiber in
> >two
> > grades. These are a
> > 400 MHz-km grade (representing the worst
>installed
> >base
> > grade of 50 um) and
> > a newer 500 MHz-km grade that allowed the SX
> >solution to
> > meet the 550 m
> > distance objective. I don't think customers
>have had
> >a
> > difficult time
> > getting GbE technologies to work in this
>situation.
> >But we
> > are sensitive to
> > this issue. So recognizing the need to
>distinguish
> >new MMF
> > from old, Lucent
> > has made the new fiber easily identifiable.
>New MMF
> >cable
> > and patch panels
> > are distinctly color coded to distinguish
>them from
> >other
> > fiber types.
> >
> > I cannot predict the percentage of new
>versus old
> >fiber,
> > since I don't have
> > a crystal ball. But I believe it will be a
> >significant
> > amount with
> > conversion accelerating as other fiber
>suppliers
> >come on
> > line. Lucent
> > already shipped hundreds of kilometers of
>new MMF
> >and we are
> > still ramping
> > up production. Also, I believe that
>deployment will
> >tend to
> > occur most
> > rapidly in those customer sites that intend
>to use
> >10GbE
> > equipment in the
> > near term. So the absolute percentage
>conversion is
> >not the
> > key indicator to
> > monitor, but rather the conversion occurring
>in
> >10GbE
> > customers sites.
> >
> > When I look at the 10 port types, I see them
>serving
> >several
> > types of
> > customers. I believe that it will be a rare
>customer
> >that
> > must make a choice
> > between all 10 types. The norm is likely a
>choice
> >between a
> > small subset
> > that is targeted for their needs. While most
>of the
> >choices
> > will not apply
> > for any one customer, all of the choices
>have their
> >purpose
> > in serving the
> > entire customer base. Let's not loose site
>of the
> >fact that
> > 802.3 is
> > entering new market spaces. These new spaces
>are
> >embodied in
> > the 10 and 40
> > km distance objectives that far exceed the
>scope of
> >building
> > cabling (the
> > scope of Ethernet up to now), and PHY
>objectives
> >which
> > address both LAN and
> > WAN. Larger and more diverse market spaces
>will
> >naturally
> > need a greater
> > variety of solutions.
> >
> > Regards,
> > Paul Kolesar
> >
> >
> >
>