RE: [10GBASE-T] PAR and 5 critters
George:
We at Vativ always maintained that 10Gbps is theoretically feasible over a
distance of 100 meters on CAT-7 cabling. In fact, we were the first company
to say that. I refer you to the following URL:
http://grouper.ieee.org/groups/802/3/10GBT/public/mar03/sallaway_1_0303.pdf
In the same presentation, we said that the goal of 100 meter transmission at
10Gbps data rate is unachievable on CAT-5e and CAT-6 cables. We followed up
these results with a 3-PHY vendor joint presentation in May 2003. We also
pointed out some of the practical considerations that need to be addressed
in both of these presentations.
My disagreements with you stem from your claims regarding 10Gbps
transmission at 100 meters over CAT-5e and CAT-6 cables. You insisted that
10Gbps data rate was achievable on 100 meter CAT-5 cables (November 2002
Plenary). I am attaching URLs to two of your presentations to underscore
these claims.
Presentation 1:
http://grouper.ieee.org/groups/802/3/10GBT/public/jan03/jones_2_0103.pdf
Presentation 2:
http://grouper.ieee.org/groups/802/3/10GBT/public/nov02/diminico_1_1102.pdf
In both of these presentations, yourself & your colleagues at Solarflare
claimed that 100 meter distance was achievable on CAT-5 cables. In
Presentation 2, page 9, Solarflare specifically claimed that 100 meter
distance was achievable on CAT-5, and that this was possible due to MIMO &
FEXT mitigation. Of course, no presentation to my knowledge had
independently verified Solarflare's claims in these presentations with
technically repeatable results. Once again, if such presentations exist,
please inform us.
But now you are saying that 10Gbps is doable on some cables at some distance
in some installations. Such a vague goal cannot be the basis for
standardization work.
Sreen Raghavan
Vativ Technologies
-----Original Message-----
From: owner-stds-802-3-10gbt@majordomo.ieee.org
[mailto:owner-stds-802-3-10gbt@majordomo.ieee.org] On Behalf Of George
Zimmerman
Sent: Wednesday, July 30, 2003 1:34 PM
To: [unknown]
Subject: RE: [10GBASE-T] PAR and 5 critters
Sreen -
I will continue to treat you with respect, and assume that somehow I
misunderstand the tone of your email. I can answer your arguments, but
then let us focus back on the PAR & 5 criteria.
I believe that we have now discussed the shortcomings of the assumptions
of your analysis. If you wish to go do work we can discuss it forward.
The process of building consensus is not the same as a full disclosure
of algorithms & architectures. In the interest of moving things
forward, we have focused on building broad market potential looking at
the installed base. The capacity results presented in the consensus
proposal assumed no alien NEXT mitigation and still addressed > 60% of
the installed base at 50meters. We can do better, but surely you can
agree that 10 Gigabit transmission is feasible on some length of Class D
or E cabling. Even you signed on to presentations proposing 10 Gigabit
on Class F cabling, do you now wish to withdraw that proposal?
I believe that you misunderstood me on the email - installation based
alien NEXT mitigation is found in the presentations I referenced, as I
stated. With regards to receiver-based alien NEXT mitigation, we were
asked to present an example of this, and we presented such an example
(not a definitive tutorial, nor necessarily the best or only technique)
at the last meeting - it appears that at least some folks on the
reflector have caught on to it. I understand that you disagree with the
results, but they are what they are.
With regards to complexity, system and AFE requirements are reflected in
the Massana analysis. I would NOT claim computational complexity
reduction is entirely due to MIMO, nor did we claim that in November, as
we did give examples of multi-rate & efficient filter implementations.
There is a lot of literature on efficient high-rate DSP, and I believe
that others have understood this issue on the reflector, and have
disagreed with you.
Let us now focus back on the PAR & 5 criteria. We all took a step
forward to technical feasibility with the text drafted (and voted in by
the SG) in San Francisco. Included within it was the feasibility on
Class F, based on statements & proposals backed by Vativ & others, also
included were statements that Class D & E could support 10G, with
acknowledgement that specification augmentation might be in order.
These are concessions for building consensus, even without Alien NEXT
mitigation of any sort. As far as technical feasibility is concerned, I
believe it answers the capacity concerns raised, and I have seen
agreement & public statements by other PHY companies that this is
feasible (though not in the meeting).
As far as broad market potential is concerned, looking at something like
99% of the installed base in 2005 being Class D & E, and between 60-70%
being less than 50meters, that represents a broad market
George Zimmerman
gzimmerman@solarflare.com
tel: (949) 581-6830 ext. 2500
cell: (310) 920-3860
> -----Original Message-----
> From: Sreen Raghavan [mailto:sreen-raghavan@vativ.com]
> Sent: Wednesday, July 30, 2003 12:18 PM
> To: George Zimmerman; sreen@vativ.com; 'DOVE,DANIEL J
(HP-Roseville,ex1)';
> 'Alan Flatman'; 'Kardontchik, Jaime'
> Cc: '[unknown]'; 'Sterling Vaden'
> Subject: RE: [10GBASE-T] PAR and 5 critters
>
> George:
>
> I have gone thru' these presentations. I do not see any of these
> presentations verifying your claims on:
>
> 1. Receiver ANEXT mitigation techniques,
> 2. MIMO somehow collapsing the DSP complexity (a claim Solarflare made
> during Nov 2002 IEEE meeting).
>
> You claim that above techniques are essential to the feasibility of
10G
> over
> CAT-5e, but you never provided any MATLAB models to the group to
verify.
> In
> addition, you said in November 2002 that 10G was feasible over 100
meters
> of
> CAT-5e. Due to careful mathematical analysis done by Vativ (and made
> available to the group MATLAB models to verify) and other companies
over
> past 9 months, majority in the group are now convinced that your claim
is
> false.
>
> I believe that you must adhere to due scientific process to support
your
> claims.
>
> Sreen
>
> -----Original Message-----
> From: George Zimmerman [mailto:gzimmerman@solarflare.com]
> Sent: Tuesday, July 29, 2003 5:52 PM
> To: sreen@vativ.com; DOVE,DANIEL J (HP-Roseville,ex1); Alan Flatman;
> Kardontchik, Jaime
> Cc: [unknown]; Sterling Vaden
> Subject: RE: [10GBASE-T] PAR and 5 critters
>
> Presentations are given by individuals, not companies, but you can
find
> them on the 10GBASE-T study group site. Among those of note are a
> January presentation from Stephen Bates, up to one just in July by
Shadi
> AbuGhazaleh & Rehan Mahmood (there are more on mitigation and on
> feasibility studies, Ron Nordin & Vanderlaan, Albert Vareljian, Bijit
> Halder all come to mind).
>
> There really isn't any mystery here - going to shorter distances
> increases the received signal proportionally, and mitigating alien
NEXT
> decreases the noise, hence, more capacity. What is more, because the
> crossover point (signal/noise=1) occurs at a higher frequency, only
> increasing the capacity further.
>
> George Zimmerman
> gzimmerman@solarflare.com
> tel: (949) 581-6830 ext. 2500
> cell: (310) 920-3860
>
> > -----Original Message-----
> > From: Sreen Raghavan [mailto:sreen-raghavan@vativ.com]
> > Sent: Tuesday, July 29, 2003 4:24 PM
> > To: George Zimmerman; sreen@vativ.com; 'DOVE,DANIEL J
> (HP-Roseville,ex1)';
> > 'Alan Flatman'; 'Kardontchik, Jaime'
> > Cc: '[unknown]'; 'Sterling Vaden'
> > Subject: RE: [10GBASE-T] PAR and 5 critters
> >
> > George,
> >
> > Please indicate which company's presentation has independently
> confirmed
> > your claims, and where I can find such a presentation.
> >
> > -----Original Message-----
> > From: George Zimmerman [mailto:gzimmerman@solarflare.com]
> > Sent: Tuesday, July 29, 2003 3:16 PM
> > To: sreen@vativ.com; DOVE,DANIEL J (HP-Roseville,ex1); Alan Flatman;
> > Kardontchik, Jaime
> > Cc: [unknown]; Sterling Vaden
> > Subject: RE: [10GBASE-T] PAR and 5 critters
> >
> > Sreen & all -
> > I believe some clarification is in order.
> >
> > What the presentation you reference from Portsmouth, New Hampshire
> > showed was that with an assumption of a high-degree of alien NEXT
and
> a
> > further assumption that it could not be mitigated in any way,
> cat5e/cat6
> > could not support 100meter operation at 10G. This is a different
> > statement altogether as to whether cat5e/6 can support 10G either
with
> > alien NEXT mitigation, or at shorter reaches, both of which have
been
> > shown to yield sufficient capacity to allow 10G in numerous
> > presentations by multiple vendors.
> >
> > The consensus proposal presented at San Francisco argued that even
> > without alien NEXT mitigation, there was a sufficient portion of the
> > installed base of 5e & 6 coverable to merit broad market potential
> (>60%
> > installed base at 50m or less), and that in addition to SolarFlare
> > showing both receiver-based (DSP) and installation-practices based
> alien
> > NEXT mitigation examples, other companies have now shown
significant
> > alien NEXT mitigation through installation practices.
> >
> > These developments significantly change the capacity relations you
> refer
> > to, making 10GBASE-T practical on the economically feasible
installed
> > base of cat5e & 6.
> >
> > On your technical points for implementation, I respectfully
disagree,
> > and we have put forward our requirements, and these have been
> confirmed
> > by at least one independent presentation.
> >
> >
> > George Zimmerman
> > gzimmerman@solarflare.com
> > tel: (949) 581-6830 ext. 2500
> > cell: (310) 920-3860
> >
> > > -----Original Message-----
> > > From: Sreen Raghavan [mailto:sreen-raghavan@vativ.com]
> > > Sent: Tuesday, July 29, 2003 1:58 PM
> > > To: 'DOVE,DANIEL J (HP-Roseville,ex1)'; sreen@vativ.com; 'Alan
> > Flatman';
> > > 'Kardontchik, Jaime'
> > > Cc: '[unknown]'; 'Sterling Vaden'
> > > Subject: RE: [10GBASE-T] PAR and 5 critters
> > >
> > >
> > > Dan:
> > >
> > > We are really referring to the theory (Shannon Capacity) when we
say
> > > 10Gbps
> > > cannot be achieved over CAT-5e or CAT-6 cabling. Theory shows that
> > 10Gbps
> > > can be achieved over CAT-7 cabling. Practical issues to accomplish
> > 10Gbps
> > > over CAT-7 cabling include (assuming PAM-10 modulation):
> > >
> > > 1. Building an 11-bit effective ADC at 833 MBaud,
> > > 2. Performing large number (x8 relative to 1000BaseT) of DSP
> > calculations
> > > at
> > > 833MHz,
> > > 3. DDFSE critical path to be implemented in 1.2 ns
> > > 4. Building a linear transmit driver with an 833MGz bandwidth & 40
> dB
> > SNR
> > >
> > > The above list by no means is exhaustive, but shows the
> implementation
> > > issues that need to be considered.
> > >
> > > Sreen
> > >
> > > -----Original Message-----
> > > From: DOVE,DANIEL J (HP-Roseville,ex1) [mailto:dan.dove@hp.com]
> > > Sent: Tuesday, July 29, 2003 1:09 PM
> > > To: 'sreen@vativ.com'; 'Alan Flatman'; 'Kardontchik, Jaime'
> > > Cc: '[unknown]'; 'Sterling Vaden'
> > > Subject: RE: [10GBASE-T] PAR and 5 critters
> > >
> > > Hi Sreen,
> > >
> > > One thing that occurs to me on this point is the difference
between
> > > theory and application. Specifically, how many process actions
have
> to
> > > take place within a baud time to close the loops on the DSP and
what
> > > process geometry would be required to make that timing closure?
> > >
> > > I know that with 1000BASE-T, the theory was rock solid long before
> the
> > > processes to implement it were reliable.
> > >
> > > Dan
> > > HP ProCurve
> > >
> > > > -----Original Message-----
> > > > From: Sreen Raghavan [mailto:sreen-raghavan@vativ.com]
> > > > Sent: Tuesday, July 29, 2003 11:52 AM
> > > > To: 'Alan Flatman'; 'Kardontchik, Jaime'
> > > > Cc: '[unknown]'; 'Sterling Vaden'
> > > > Subject: RE: [10GBASE-T] PAR and 5 critters
> > > >
> > > >
> > > >
> > > > Just to clarify, Vativ, Broadcom & Marvell presented capacity
> > > > calculations
> > > > at the Portsmouth meeting and showed that worst-case CAT-7
> > > > (Class F) cabling
> > > > had sufficient channel capacity to achieve 10Gbps throughput
> > > > at 100 meter
> > > > distance. The reason for "may be possible" statement in the
> > > > conclusions was
> > > > that the 3 PHY vendors felt that more work needed to be done
> > > > on practical
> > > > implementation issues before the conclusion could be altered to
a
> > more
> > > > definitive statement.
> > > >
> > > > In addition, we proved conclusively that there was NOT
> > > > sufficient channel
> > > > capacity on existing CAT-5e (Class D), or CAT-6 (Class E)
> > > > cables to achieve
> > > > 10 Gbps throughput.
> > > >
> > > > Sreen Raghavan
> > > > Vativ Technologies
> > > >
> > > > -----Original Message-----
> > > > From: owner-stds-802-3-10gbt@majordomo.ieee.org
> > > > [mailto:owner-stds-802-3-10gbt@majordomo.ieee.org] On Behalf
> > > > Of Alan Flatman
> > > > Sent: Tuesday, July 29, 2003 9:51 AM
> > > > To: Kardontchik, Jaime
> > > > Cc: [unknown]; Sterling Vaden
> > > > Subject: RE: [10GBASE-T] PAR and 5 critters
> > > >
> > > >
> > > > Message text written by "Kardontchik, Jaime"
> > > > >Was any reason given why it would not run on Class F ? Was it
for
> > > > technical reasons or for marketing reasons ?<
> > > >
> > > > The 3-PHY vendor presentation made in Portsmouth
(sallaway_1_0503)
> > > > calculated 49.36 Gbit/s capacity using unscaled Cat 7/Class F
> > > > cabling. This
> > > > figure was reduced to 37.71 Gbit/s with worst case limits.
> Overall,
> > I
> > > > thought that this was a refreshingly realistic presentation and
I
> > > > interpreted the summary statement "Capacity calculations with
> > > > measured data
> > > > indicate 10 Gigabit data transmission over 100m Cat 7 may be
> > possible"
> > > > (slide 16, bullet 3) as overly cautious engineering judgement.
> > > >
> > > > So, what has changed since the May interim? Not the laws of
> physics!
> > > >
> > > > Best regards,
> > > >
> > > > Alan Flatman
> > > > Principal Consultant
> > > > LAN Technologies
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>