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Re: [10GMMF] Optical Cable references in LRM Draft

Title: Message
Happy New Year - hope you had a good holiday and some time to rest up for an exciting 2005.
I have to respectfully disagree with your observation that you don't think we have to specify cable - applications run on cable, 11801 specifies cable and the cable and fibre specifications are different. Generally, fibre specifications are more stringent (e.g., attenuation and the environmental specifications) than cable specifications. Our power budget must be based on a 3.5dB/km value of cable, not the 2.5 dB/km value typically specified on fibre. This has caused confusion in the past in the marketplace and the only real reason we did not fix it previously is that we had no cable specifications to specify - now we do and we should reference them. It really doesn 't change any functional requirements and I believe that the 60794 series does not disenfranchise any of the installed base (unless it did not meet 11801 in the first place, which in my mind does not meet our requirements).
Regarding your other questions:
1. The 60794 series specifies both optical and environmental requirements; the optical requirements reference OM-1, OM-2 and OM-3 fibre specifications so they are identical with the exception of attenuation. The only environmental requirement specified in the 60794 series is temperature cycling which is specified at -20 to 60 consistent with the requirement in 11801 for indoor cable. There are specifications for duplex, multi-fibre and ribbon cables in the -2 series. The -3 series specifies outdoor cable and we could add those as references also.
2. "PAS" means "Publicly Available Standard" and is a new process used by IEC to get standards to the market quickly (or quicker). Basically, it allows the committee to make the standard "available" after the completion of a successful CDV (Committee Draft for Vote) ballot. The PAS is then replaced by the "official" published standard once it completes FDIS (Final Draft International Standard) ballot.
3. Regarding the question on fibre types, 60793-2-10 specifies all multimode fibre types and 60793-2-50 specifies all single-mode fibre types. The cable specifications specify both fibre types in a single document, i.e., 60794-2-11 covers duplex cable for premises applications for BOTH multimode and single-mode fibres and references the multimode fibres in 60793-2-10  and the single-mode fibres in 60793-2-50. 60794-3-12 covers duct and directly buried cable (read outdoor) for premises applications for BOTH multimode and single-mode fibres and references the multimode fibres in 60793-2-10  and the single-mode fibres in 60793-2-50.
Hope that helps; let me know if further clarification is needed.
-----Original Message-----
From: Piers Dawe [mailto:piers_dawe@AGILENT.COM]
Sent: Thursday, January 06, 2005 8:35 AM
Subject: Re: [10GMMF] Optical Cable references in LRM Draft

Steve, thanks for providing us with this information.
At the last meeting, I said that your proposal to change from "The fiber optic cable shall meet the requirements of IEC 60793-2, ..." to "the fiber optic cable shall meet the requirements of IEC 60794-2-11,..." needed more study.  One reason is that your proposed wording was restrictive rather than permissive.  It wouldn't mean "cable to IEC 60794-2-11 is OK", it would mean "any other cable is not OK".  I do not believe that.  For example, IEC 60794-2-11 specifies "indoor optical fibre cables".  We don't want to forbid people extending Ethernet to outdoor use!
We are constrained by the past.  The main purpose of the 802.3aq project is to allow people to re-use existing cable plant, which could be old.  IEC 60794-2-11 is very new (published March 2004) and it would be unreasonable to expect users to consider some kind of qualification after the event.  We are pretty much stuck with using the specifications of 52.14.1 (mentioning IEC 60793-2).  We can consider adding a new permissive statement saying that cable to IEC 60794-2-11 MAY be used - but see below.
I notice that IEC 60794-2-11 is a CABLE specification while IEC 60793-2 is a FIBRE specification.  While I could imagine that for electrical cabling, it would be hard to make such a separation, for us the optical transmission characteristics are pretty much defined by the (fiber) parameters as e.g. in table 68-6.  I don't think we need to define the cable: we (802.3aq) aren't defining structured cabling nor attempting to regulate the installation industry - we let someone else do that e.g. through ISO/IEC 11801.
To judge the appropriateness of IEC 60794-2-11 you'll have to give us more information.  What does it specify?  The weight of a cable?  Color?  Strength?  Temperature and environmental ratings?  This clause following others (52.11.1) basically mentions "reasonable conditions" and says that the detail is beyond the scope of this standard.  So I don't yet see what benefit IEC 60794-2-11 brings to this clause.
By the way, what does the "PAS" in "IEC/PAS 60794-2-11" (from the IEC web site) mean?
In your email below you say "two fiber types that we call out, i.e. 60793-2-10 and 60793-2-50".  Did you mean -50 "Optical fibres - Part 2-50: Product specifications - Sectional specification for class B single-mode fibres" or another part?  Anyway, we don't yet have specific references to parts of 60793-2 in the draft, though we mention 60793-2-10 in the objectives.  Do we need to add IEC 60793-2-10 to the list of references or is the reference to IEC 60793-2 enough?  And then would we need to refer to an old version of IEC 60793-2-10?
-----Original Message-----
From: owner-stds-802-3-10gmmf@IEEE.ORG [mailto:owner-stds-802-3-10gmmf@IEEE.ORG]On Behalf Of Swanson, Steven E
Sent: 29 November 2004 14:58
Subject: [10GMMF] Optical Cable references in LRM Draft

At the meeting in San Antonio, I agreed to provide additional justification for my comment to replace the title of 68.9.1 and the reference given from fiber references to cable references (see Swanson comments 65 and 66). I have copied the scope and Normative references from the recommended reference - note that this cable document is intended to ensure compatibility with IS 11801 and references the two fiber types that we call out, i.e. 60793-2-10 and 60793-2-50.



IEC 60794-2-11
Part 2-11: Indoor optical fibre cables -
Detailed specification for simplex and duplex cables for use in premises cabling

1 Scope
This Standard presents the detailed requirements specific to this type of cable to ensure compatibility with IS 11801 [1], Information technology - Generic cabling for customers premises. The requirements of the Family Specification IEC 60794-2-10 are applicable to cables covered by this standard.

2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

IEC 60794-2-10, 2003 : Optical fibre cables - Part 2-10: Indoor optical fibre cables - Family Specification for simplex and duplex cables

IEC 60793-2-10, 2002 : Optical fibres - Part 2-10: Product specification - Sectional specification for category A1 multimode fibre

IEC 60793-2-50 Ed. 2 : Optical fibres - Part 2-50: Product specification - Sectional specification for class B single-mode fibre