Re: [802.3BA] 802.3ba XR ad hoc next step concern
At 06:35 PM 8/25/2008 , Swanson, Steven E wrote:
think the 1/12 failures would only occur if all links were 150m. If you
believe the Flatman survey, 90% of links are less than 100m so 90% of the
links will work all of the time with a standard that is designed to
support 100m. Even if the other 10% are all 150m, the failure rate is
less than 1% overall. I think the number less than 100m is smaller than
90% but even if it was 80%, the failure rate would be less than 2%
overall. And this also assumes that EVERYTHING is worst case. If one
always designs for worst case, we incur unnecessary costs and place our
customers in a difficult position.
That is not the way I read this.
My read is:
- Approximately 100% (99 44/100+%) of the links that are less than
100 meters will work all of the time.
They are the mass of the market and they are NOT the
topic of discussion.
Given the relatively small market for links that are between 100m and
150m long, we have the following questions:
- How big is this market compared to the sub-100 meter
- What are the odds that just using 100 meter hardware will just
work given the various margins and the miracle of statistics?
- How much of a premium could vendors demand over 100 meter
hardware to satisfy this market (at the same performance assurance level
as the sub-100 meter market)?
- How much of a premium would the whole market tolerate to lump
this market with the sub-100 meter market?
- What could be done to mitigate this problem without changing the
hardware (e.g. informative annexes)
- What percentage of this market can be handled by various other
And when all of these questions are answered, we will be left with the
If we don't draw the line at 100 meters, where do we draw it?
The question DOES NOT GO AWAY when we move the line from 100 meters to
It just changes:
- The numbers from 100/150 to 150/something else
- The populations on each side of the hash
- The costs of the device