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All, 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 ——————————————————————— Jeffery J. Maki, Ph.D. Principal Optical Engineer Juniper Networks, Inc. Desk +1-408-936-8575 Lab +1-408-936-1169 (Please leave messages by email.) FAX +1-408-936-3025 www.juniper.net ——————————————————————— IEEE 802.3 voter, OIF voter, & EA alternate voter Member of OSA, LEOS, & IEEE ——————————————————————— From: Robert Snively [mailto:rsnively@xxxxxxxxxxx] Folks, 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 408-835-4321 From: Chris Cole
[mailto:chris.cole@xxxxxxxxxxx] 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 Chris From: Ryan Latchman [mailto: 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, Ryan From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxx] Chris |