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Re: [HSSG] 40G MAC Rate Discussion


I'd like to address your comment about being puzzled over why this issue
has raised a debate.  I do not disagree with many of your points below
and believe that it is always possible to develop a technical solution
to nearly any given problem.

The debate, at least from my point of view, revolves around whether this
is the right direction for Ethernet and the component vendors, equipment
vendors and end users.  Fundamentally we all are in the business to make
money and Ethernet has been a successful in enabling this due to a
number of factors.   Primarily this has been due to the economies of
scale that come from many the needs and applications being served by a
common solution.  

Arriving at a common solution is the hard work that takes place in the
standardization effort that makes us sure that we build enough options
to meet the needs but not too many.  The number of PMDs supported is a
good example of this and traditionally I think 802.3 has made a good
effort to restrict the list of PMDs to a minimum to support the
application.  I think there are a number of good examples of where this
happened well and didn't happen well.

I think the scrutiny level between pre-bubble and now is different and
we have seen this already in the discussions that have happened within
HSSG.  The level of debate and discussion that have driven the
convergence towards PAR A has covered, debated and dismissed a lot of
options.  There appears to be a strong need to be sure we are converging
on a solution that addresses a market need and that the ROI of doing
that development is attractive.

The 40GE discussion has raised the understanding that the
networking/aggregation requirements may be different from those of the
server/computing requirements.   I think the debate is really hinging
around whether it makes market sense to address these two requirements
with a common solution or dual solutions and what the implications of
that would be.   Given the changes we are hearing about in data center
architectures and server markets (eg rise of blade servers), I interpret
the 40G/100G debate to be based on a need to better understand what
creating an additional 40GE market enables to all interested parties vs
the common solution.

Personally, I feel that LAN PHY, WAN PHY is a good example of when we
did not make the decision to have a common solution.  I would suggest
that the 802.3 vs 802.12 is another example.   

I'm not saying that 40GE and 100GE can not or should not co-exist but I
want to make sure I have a clear understanding of the opportunities and
risks to making that decision.  I think there has been considerable data
brought forward to help us understand the breadth of applications and
needs for 100GE in the aggregation space.  I am hoping to get a much
better insight into the equivalent for 40GE so I can make an evaluation
of the risks and opportunities.


> -----Original Message-----
> From: Shimon Muller [mailto:Shimon.Muller@Sun.COM] 
> Sent: Monday, April 02, 2007 7:52 PM
> To:
> Subject: Re: [HSSG] 40G MAC Rate Discussion
> Thank you for the clarification, John.
> On that point, as someone who started the 40Gb discussion 
> back in January, I would like to make it clear in no 
> uncertain terms what our motivations were and still are: in 
> no way do we intend to impede or slow down the development 
> and/or the adoption of 100Gb Ethernet.
> We believe that doing a standard for 100Gb is important but 
> not enough, for the following reasons:
> - The 40Gb speed will enable us to get the most out of our 
> servers until 100Gb becomes technically and economically 
> viable for server connectivity. We believe that there is a 
> 5-year window of opportunity for this market.
> - The two speeds should be addressing two distinct markets. 
> This can be accomplished by defining the PMDs based on reach, 
> with 40Gb defined for short-reach datacenter connectivity only.
> - 40Gb connectivity at the server will require a faster 
> aggregation speed even in the datacenter. This will increase 
> the market potential for 100Gb.
> - Unless the 100Gb effort starts today, the technology will 
> not be ready when we need it for servers in 2015. I am sure 
> your heard me say this at the last meeting, and I meant it.
> - The development of a 40Gb standard will be highly 
> leveraged: either from the work that was done in other 
> standards bodies, or from the work that needs to be done for 
> 100Gb anyway. Therefore, 40Gb should in no way slow down the 
> 100Gb effort.
> What has been puzzling to me in this debate ever since it started is:
> how can 40Gb server connectivity in the datacenter hurt those 
> of you who believe that 100Gb is the right speed for 
> aggregation links in service provider networks? I am 
> certainly at a point where I understand and respect the needs 
> of your market. All I am asking in return is the same.
> Any comments that will help me understand and address the 
> above concerns would be very much appreciated.
> Regards,
> Shimon.
> John DAmbrosia wrote On 03/30/07 19:48,:
> > All,
> >
> > From discussions I have had, I sense that there may be some 
> confusion 
> > regarding the proposal for adding a 40Gb/s MAC rate 
> objecitve. 40 Gb/s 
> > has been proposed as an additional MAC rate, not as a 
> replacement for 
> > the current objective of 100 Gb/s.
> >
> > The presentations given have focused on the needs of servers / end
> > stations:
> >
> > 
> > pdf
> >
> > 
> > .pdf
> >
> > 
> > 7.pdf
> >
> > I encourage all to review the above presentations, and use the 
> > reflector to further discuss them and / or the proposed objective.
> > This will help to assist the SG in preparing for the April 
> Interim, as 
> > well as making decisions regarding the project's objectives.
> >
> > Best Regards,
> >
> > John D'Ambrosia
> >
> > 
> ----------------------------------------------------------------------
> > --
> >
> > *From:* John DAmbrosia [mailto:jdambrosia@FORCE10NETWORKS.COM]
> > *Sent:* Monday, March 26, 2007 5:11 PM
> > *To:*
> > *Subject:* [HSSG] 40G MAC Rate Discussion
> >
> > Dear HSSG Members,
> >
> > As discussed in the action plan pulled together at the end of the 
> > plenary week, further discussion on adding a 40G MAC rate as an 
> > objective is needed. Topics of interest include: economic 
> feasibility, 
> > broad market potential, and what pmds are desired for this rate.
> >
> > I would like to encourage all to use the reflector for this subject 
> > matter, which could assist individuals in their 
> preparations for the 
> > interim meeting next month.
> >
> > Best Regards,
> >
> > John D'Ambrosia
> >