Re: [10GBASE-T] PAR and 5 critters
I am assuming worst case four connector channels as defined by the
appropriate standards. 2 connector channels are a form of mitigation,
and are not standards based.
Note that ISO/IEC 11801 states:
"Most class F channels are implemented with two connections only.
Additional information concerning this implementation is given in Annex H".
Sterling Vaden
Doug.Coleman@corning.com wrote:
>It is my impression that the lengths below are contingent upon using two
>interconnects. How does the use of two cross-connects effect length
>capability?
>
>Regards,
>
>Doug Coleman
>
>
>
>
> Sterling Vaden
> <sterlingv@bellsouth.net> To: stds-802-3-10gbt@ieee.org
> Sent by: cc: "[unknown]" <stds-802-3-10gbt@ieee.org>
> owner-stds-802-3-10gbt@majordom Subject: Re: [10GBASE-T] PAR and 5 critters
> o.ieee.org
>
>
> 07/30/2003 09:40 AM
>
>
>
>
>
>
>While I understand the motive behind stressing the benefits of DSP based
>ANEXT compensation, and installation based ANEXT mitigation, I have to
>emphasize that these methods and their practical value are subject to
>ongoing debate. For example, one of the ANEXT mitigation methods is to
>insert patch cords of longer length/geater insertion loss into the channel.
>This is not only counter-intuitive it has other problems as well, such as
>the possibility of re-qualifying the channel for length and insertion loss,
>as well as possibly violating TIA requirements for patch cord wire gauge
>and insertion loss assumptions. For the formulation of the 5 critters, I
>contend these arguments are non-starters. All of these things, however can
>be cosidered and debated on their merits in the task group. Please try to
>focus on establishing a baseline position that everyone can support by
>indicating your support for the following options:
>
>Class F at 100 meters
>Class E STP at 100 meters
>Class E UTP at 50 meters
>
>ADC feasibility for above configurations
>
>Commitment to develop:
>
> Cabling performance standards for:
> Class D STP
> Class D UTP
>
> Retrofit based mitigation techniques for:
> Class E UTP > 50 meters
> Class D STP ?
> Class D UTP (dependent upon result of cabling standards developed
>above)
>
> DSP based ANEXT cancellation
>
> ADC feasibility for the above configurations
>
>Based upon level of support for these objectives, we can add new objectives
>or delete/augment. Remember, the objectives must have broad support within
>the group to survive at higher levels of approval.
>
>Sterling
>
>
>George Zimmerman wrote:
>
>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 Zimmermangzimmerman@solarflare.comtel: (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 Zimmermangzimmerman@solarflare.comtel: (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
>
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