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Hi Ali; If such idea for QSFP is foreseeable for
the sake of port density, donot you think it will be great to move XR into an annex
of the draft? I suggest this should be re-visited during CC. I feel the resistance from the group for
the reason XR may potentially compete against others like 100m option, actually
it is just a complimentary. Frank From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxx] John As we go from 10GbE to 100GbE, there is an evolutionary transition
in infrastructure – a larger portion of the link distance must and will be
cost-effectively covered by MM fiber, but the 802.3ba objectives don’t reflect
this. For 10GbE 10G-T, 802.3an had an objective to support up to 55m
(class E) and 100m (class F) on copper. http://ieee802.org/3/an/public/mar04/agenda_1_0304.pdf But for 100GbE 802.3ba we now have an objective for 10m on copper http://ieee802.org/3/ba/public/jul08/agenda_01_0708.pdf Thus for 100GbE the 10-100m length must now be covered by fiber.
This can be done in the most cost-effective way by taking the OM3 fiber and
850nm lasers used for 10GbE for 100-300m applications and streamlining them for
this application. This is implicit in the existing MM objective. The full
capability of 10GbE 850nm VCSELS and OM3 fiber is not needed for most if not all
of this length range at 100GbE, since they were designed for 300m in 802.3ae,
and cost reduction opportunities exist. However, a portion of the 100-300m range covered by OM3 fiber in
10GbE will still be needed for 100GbE applications in data centers. Fiber suppliers
such as In analyzing the distribution of lengths in data centers and high
performance computing environments, it is a fact many of the short links are
currently copper. It is a mistake for us to think that because the
shorter lengths will now be MM fiber, that there is no need for the longer
lengths currently supplied. This mistake is an artifact of how the data
is being presented. It is absolutely contrary to the interests
of the end users for 802.3ba to neglect the 100-150m length segment with a
simple low-cost OM3 MM solution. From: Geoff and Steve, For customers wanting TP links further
than 100 meters, I thought we pointed them to ISO 11801 and TIA568B which
recommend fiber :)) for such runs. Bruce From: Geoff
Thompson [mailto:gthompso@xxxxxxxxxx] At 06:35 PM 8/25/2008 , What should we tell our customers who have
link lengths longer than 100m and want (or require) a standardized solution?
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