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Re: [802.3BA] XLAUI / CAUI Ad Hoc


All the work I have done on the XLAUI/CAUI included on connector (SFF-8083) so the xAUI electrical specifications
does support 8" of standard grade FR4 or about 15" of improved FR4 with addition of one connector.

PPI is being defined based on detail definition of HCB and MCB.  A generic definition may be too slack which will cause interoperability issues or
too tight which will reduce the host PCB trace length, on the other hand PPI HCB/MCB definition may not be realizable with first Gen 100G modules
due to the size.

I have been told just define something and the implementers will work with it, then I would say lets just use CL86 MCB/HCB


Jeffery Maki wrote:



I too wish to speak in favor of XLAUI and CAUI including chip-to-module specifications.  The specifications should align, or at least not be in conflict with, the likely instantiations to be found in the market.  A chip-to-chip specification should also still be made.  I hope there is a way to cover the signal integrity issues of a connector without specifying its exact mechanical nature.  Can something similar be done as was for PPI?





Jeffery J. Maki, Ph.D.

Principal Optical Engineer

Juniper Networks, Inc.

1194 North Mathilda Avenue

Sunnyvale, CA  94089-1206

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(Please leave messages by email.)

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IEEE 802.3 voter, OIF voter, & EA alternate voter

Member of OSA, LEOS, & IEEE




From: Robert Snively [mailto:rsnively@xxxxxxxxxxx]
Sent: Monday, December 29, 2008 6:44 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XLAUI / CAUI Ad Hoc




My concern is that specifying a chip to chip implementation sets one set

of requirements focused on low signal power, low emissions, and fairly

tightly specified channel definitions.  A chip to module implementation

set of requirements focuses on slightly greater signal power, controlled

rise times, managed pre-emphasis and equalization, and a broader range

of channel definitions that include connectors.


If we succeed in a chip to chip implementation that does NOT have

the chip to module implementation requirements considered, then all

architectures will require intermediate transceivers on the motherboard

between the protocol ASIC and the module, measurably impacting

cost, complexity, reliability, and power.  XFI was focused specifically

on chip to ASIC implementations, using a module CDR to improve the jitter

budget in the tightly constrained SR environment.  As such, it may be a

good starting model.


It would be better to have no chip to chip implementation in this revision

of the standard if that implementation precludes chip to module implementations

using a single definition of ASIC I/O circuitry.


Bob Snively



From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Monday, December 29, 2008 6:02 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XLAUI / CAUI Ad Hoc

Hi Ryan,


You are right that the nAUI chip to chip specification methodology in draft 1.1 can be leveraged to build retimed modules. It just requires writing a chip to module specification somewhere which specifies test points at the modules pins. The presentation you sent is an excellent starting point for this and a lot of the XFI interface specifications can be leveraged in writing the nAUI chip to module specifications.


Best Wishes for the New Year to Everyone




From: Ryan Latchman [mailto:Ryan.Latchman@xxxxxxxxxx]
Sent: Tuesday, December 23, 2008 10:07 AM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XLAUI / CAUI Ad Hoc


Hi Ali, Chris,


This is an important discussion which needs to get resolved quickly.


I would like to ensure that XLAUI / CAUI maintains its broad market applicability as a simple retimed interface.  I don’t think the current specification methodology prevents it from being leveraged to build retimed modules.  I’ve put together the attached material to show how retimed interfaces were specified in the past (namely XFI).  In XFI, you’ll notice that the Before Connector and After Connector specs are similar.  40/100GbE modules may have an analogous situation, depending on their size and electrical characteristics. 


If we need to change the XLAUI / CAUI specification, we need solid contributions on what needs to change. 


Happy Holidays,




From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxx]
Sent: December 22, 2008 5:59 PM
To: Chris Cole
Cc: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx; John DAmbrosia; Ryan Latchman
Subject: Re: [802.3BA] XLAUI / CAUI Ad Hoc



I just wanted to illustrate the difficulty members of 802.3ba would have in defining host-module interface for 100GBase-LR4/ER4 based on
publicly available information rather than in any way pointing to you for argument you did not make. 

You also say that specific implementation detail are inappropriate for the IEEE, but CR4/CR10, SR4/SR10 are based on very specific set of
assumptions.  The presentation I gave in Dallas, I made some very specific assumption on the module-host implementation which may be correct
or completely wrong, but we have to make some specific assumption please see page 5
Currently xAUI adhoc is defining transmitter mask instead of testing transmitter with compliance channel, in case the group decides to define
module-host compliance points then a 2nd transmitter mask must be defined at the output of module compliance board (see 2nd diagram on page 5).
In summary we have to replicate xAUI transmitter and receiver table for host and module.


fn:Ali Ghiasi
org:Broadcom Corp.
adr;dom:;;3151 Zanker Road;San Jose;CA;95134
title:Chief Architect