RE: [10GBASE-T] latency
Jonathan
Thanks for the summary
I would argue that early 10GBASE_T switching products should be sold to
early adopters at National Labs and other R&D sites building
clusters. We need this community to come to the TF and state its latency
requirement in the 2006 timeframe and determine the tradeoffs.
Bruce
At 10:54 AM 2/23/2004 -0800, Jonathan Thatcher wrote:
There have
been numerous interesting and correct comments made. A subset of these
apply only in certain contexts. To that end, I will attempt to add some
context.
There is little question that
lower latency increases the market potential. There is little question
that lower prices (read that less complexity), and earlier time to market
also increases the potential market. The problem is that these fight
against each other, and the optimization point is not
clear.
I presume that there are two
principal application spaces for 10GBASE-T in the near term: data center
and enterprise (home and school will probably have to wait a couple of
years :-). If you want a strict boundary between these two spaces, I
can't provide it. So we will have to deal with some ambiguity. In the
enterprise, it is difficult to argue that low latency is as critical as
low price. The exception to this would be low latency applications that
want to be set up as a "grid computer," which I will lump into
the "data center" bucket.
The data center, on the other
hand, has instances where both low latency is required (clustered
computing) and higher latency is acceptable (most file serving). From a
parallel computing perspective, there are classes of problems
(applications) that range from low latency NUMA to those that are
"embarrassingly parallel (e.g.
http://setiathome.ssl.berkeley.edu/)."
From the perspective of the
upcoming "Data Center Ethernet" (may not be the best name) call
for interest, the intent is to explore those means that can be used to
decrease latency in Ethernet networks. If one is to presume that this
should be a key application space for 10GBASE-T, then it would be
interesting to understand the trade-off between latency and complexity.
It may be the case, that even under the most complex scenario, that
10GBASE-T latency is simply insufficient for entire classes of low
latency applications.
So, the question remains, what
does the complexity vs latency curve look like? I expect that it is
something like the left side of a bathtub curve (vertical axis is
latency, horizontal axis is complexity). What is the inflection point?
What is the slope of the falling portion of the curve? What is the
asymptote?
jonathan
Bruce Tolley
Senior Manager, Emerging Technologies
Gigabit Systems Business Unit
Cisco Systems
170 West Tasman Drive
MS SJ B2
San Jose, CA 95134-1706
internet: btolley@cisco.com
ip phone: 408-526-4534
"Don't put your hiking boots in the oven unless you plan on
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