Re: [802.3BA] Longer OM3 Reach Objective

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Brad

There is no specified reach for backbone cabling – it is limited only by the size of the data center. So this is indeed different from horizontal cabling, which is generally limited to 100 m except when centralized optical fiber configurations are used, in which case horizontal cabling is limited to 300 m.

OM3 is the most commonly specified fiber type specified by my clients for backbone cabling in data centers. The mix of installations using parallel fibers (i.e. terminated on MPOs) increasingly common. I would say that at least half of my clients are now using fibers terminated on MPOs regardless of distances, as they simplify installation and reduce the need for skilled labor.

Regards,

Jonathan

From: Brad Booth [mailto:bbooth@AMCC.COM]
Sent: Friday, March 14, 2008 1:25 PM
To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG
Subject: Re: [802.3BA] Longer OM3 Reach Objective

Jonathan,

Can you provide some clarification for those of us not well-versed in data center fiber optic cabling installation practices?

Is there a specified reach for a backbone? Is that a different specification from horizontal cabling?

In your estimation, how many backbones have OM3 fiber deployed in them? For the 150m fiber deployments, are they parallel fibers? Or is there an assumption that WDM optics will be used?

It would help tremendously to understand these items as they relate to a possible modification of the reach and the impact in the architectures and relative costs.

Thanks,

Brad

From: Jonathan Jew [mailto:jew@j-and-m.com]
Sent: Fri 3/14/2008 12:32 PM
To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG
Subject: [802.3BA] Longer OM3 Reach Objective

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