RE: [10GBASE-T] PAR and 5 critters
Yeah, the analog target specs look reasonable ...
For comparison, in my previous life (company) I did some
system simulations (and actual design) and came to the
conclusion that one could run 10 Gbps over cat-7 STP to
a distance of about 25 meters with a 7-bit effective ADC
at 625 Mbaud (PAM-5 modulation). At least, the 7-bit
effective ADC was achievable ...
Jaime E. Kardontchik, PhD
Integration
Mountain View, CA 94041
-----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
>
>
>
>
>