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Re: [HSSG] 40G MAC Rate Discussion


One of the form factor has been discussed for  40Gig is QSFP which is only about 0.7x0.4".
Do you think you can get 4 RJ-45 in this form factor and dissipate <3.5W for Quad10GBaseT PHY?


Bill Woodruff wrote:

10GBASE-T is 100m over Cat6a or Cat7, or 55m over Cat6.  this is with 4
connectors; a full cross-connect topology per ISO-IEC-11801.  I believe
in most cases, the cabling will be field terminatable.  

The 10GBASE-T PHY supplier community will be aggressively driving power
lower, from a baseline of growing volumes.  If your desire is to see a
copper interconnect that works with structured cabling of more than 10
to 20m, and a cross-connect model with patch panels, then LAG with four
10GBASE-T links is a viable and available choice.  

The definition of 'acceptable' for any 40G solution need to be in the
context of the interconnect requirements, the target platform, and the
full chip set in that platform.  I'm sure this community can identify an
optimized 40GE solution, with 4X 10GBASE-T LAG as a existing option for

Regards, Bill

Bill Woodruff, (c) 408 582-2311
Aquantia - VP Marketing, 408 228-8300 x202

-----Original Message-----
From: Mikael Abrahamsson [mailto:swmike@SWM.PP.SE] 
Sent: Tuesday, April 10, 2007 1:04 PM
Subject: Re: [HSSG] 40G MAC Rate Discussion

On Tue, 10 Apr 2007, Ali Ghiasi wrote:

I know there is readily available solution based on QSFP that could do

40G copper with twin-ax cables.  Copper solution are very attractive 
for sub-10m as they offer order of magnitude cost advantage.  Longer 
reach cable not as attractive as you have to use heavier gage which 
increase the cable size, weight, cost, and the complexity of receiver

Well, my idea was to compare 4*10GE LAG and whatever 40GE solution is
being proposed. I understand now I should have written this outright,

My thoughts were that operational cost and CAPEX of doing 4*10GE LAG
using 10GBASE-T for servers would be quite a lot lower than any new
proposed 40GE solution, since I only saw coaxial and fiber proposed for
40GE physical media.

Or have I misunderstood 10GBASE-T when it comes to power and reach (100M
over CAT7 or ~50 on CAT6)? Does it require a lot more power than fiber
based solution?

From a pure end-user perspective CAT6-7 based cabling has the lowest
operational cost (physical only) since it's abundant and there is a lot
of experience with that kind of cabling. But perhaps it uses a lot more
power than the other proposed solutions for 40GE?


fn:Ali Ghiasi
adr;dom:;;3151 Zanker Road;San Jose;CA;95014
title:Chief Architect