Re: [802.3BA] Longer OM3 Reach Objective
"Previously when I stated the OM3 link can be extended to 300 m and with
increase link margin, the reply was there is no such application
requirements."
- not sure that is the way I remember the discussion going Ali. For me
anyways, it was centered on questioning the incremental power &
complexity/cost related to the required EDC for this optical PHY in order to
obtain the longer reach. And yes, there were a wide range of expressed
opinions on the application value of picking up some of the distribution
tails, but I never heard such a definitive statement of 'no application
requirement'.
John
-----Original Message-----
From: Ali Ghiasi [mailto:aghiasi@BROADCOM.COM]
Sent: Friday, March 14, 2008 3:41 PM
To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG
Subject: Re: [802.3BA] Longer OM3 Reach Objective
Jonathan
In Jan 08 interim meeting I presented the following presentation
http://www.ieee802.org/3/ba/public/jan08/ghiasi_02_0108.pdf
and published in IEEE communication magazine:
http://dl.comsoc.org/cocoon/comsoc/servlets/GetPerson?id=10033162
which showed even with a 4G transmitter a 300 m OM3 link has one dB more
margin
using a simple EDC (Electronic Dispersion Compensation) compare to a
limiting link operating
over 100 m of OM3 fiber, similar to:
http://www.ieee802.org/3/ba/public/mar08/pepeljugoski_01_0308.pdf.
To meet IEEE objective to support copper cable for 10 operation, some
form of EDC
would be required. As long as the copper and the optical specifications
for linear
interface are not defined in orthogonal fashion, a port supporting
copper cable can greatly
benefit a port supporting linear optics and extend the reach to 300 m!
Previously when I stated the OM3 link can be extended to 300 m and with
increase link
margin, the reply was there is no such application requirements. It is
good to hear from
people like you.
Thanks,
Ali
Jonathan Jew wrote:
> I am a consultant with over 25 years experience in data center
> infrastructure design and data center relocations including in excess of
50
> data centers totaling 2 million+ sq ft. I am currently engaged in data
> center projects for one of the two top credit card processing firms and
one
> of the two top computer manufacturers.
>
> I'm concerned about the 100m OM3 reach objective, as it does not cover an
> adequate number (>95%) of backbone (access-to-distribution and
> distribution-to-core switch) channels for most of my clients' data
centers.
>
>
> Based on a review of my current and past projects, I expect that a 150m or
> larger reach objective would be more suitable. It appears that some of
the
> data presented by others to the task force, such as Alan Flatman's Data
> Centre Link Survey supports my impression.
>
> There is a pretty strong correlation between the size of my clients' data
> centers and the early adoption of new technologies such as higher speed
LAN
> connectivity. It also stands to reason that larger data centers have
> higher bandwidth needs, particularly at the network core.
>
> I strongly encourage you to consider a longer OM3 reach objective than
100m.
>
> Jonathan Jew
> President
> J&M Consultants, Inc
> jew@j-and-m.com
>
> co-chair BICSI data center standards committee
> vice-chair TIA TR-42.6 telecom administration subcommittee
> vice-chair TIA TR-42.1.1 data center working group (during development of
> TIA-942)
> USTAG representative to ISO/IEC JTC 1 SC25 WG3 data center standard adhoc
>
>