Cable standards question

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1

Hello, newbie question of the morning time, but hopefully not too off-topic...

I run a small town network. A new building is being built that the town wants fiber access to. I have to specify for vendors what it is that the town expects in the cabling. I am (obviously) not a fiber expert, and I'm having trouble phrasing the language of the RFP so that we are assured a quality installation.

My question is this; Is there an appropriate standard to specify for fiber-optic cabling that if it is followed the fiber will be installed correctly? Would specifying TIA/EIA 568-C.3, for example, be correct?

I'm envisioning something like;

"The vendor will provide fiber connectivity between (building A) and (building B). Vendor will be responsible for all building penetrations and terminations. When installing the fiber-optic cable the vendor will follow the appropriate TIA/EIA 568 standards for fiber-optic cabling."

Any suggestions or examples of language would be very appreciated. Offlist contact is probably best.

Many thanks,

---Sam

2

Is it appropriate to just say "When installing fiber-optic cable the vendor will ensure the resulting installation does not suck."?
That would seem to me to be the most direct solution to the problem. I mean, standards are all well and good, but what if the standard sucks?
Then you'd be up a creek.

Maybe there should be a legal definition of the concept of suck, so that suckage could be contractually minimized.

3

At minimum, I think you should probably specify the type and number of fibers you want. i.e. Based on the distance and gear you'll be using, do you need single-mode, or will multi-mode do (as well as the core/cladding diameter)? Generally, but not always, fiber uses one strand for transmit and another for receive, so a typical fiber run is done using duplex fiber. Some optics can transmit and receive over one strand using different wavelengths. You might even specify how you want the fiber terminated (SC, LC, cables hanging from the wall, fiber patch panel, etc.).

4

I'd agree with this. I wouldn't worry about the standard so much as the
practical aspects of a run. Once you have an idea of the approximate
distance of the run, you can figure out which optics you plan on using.
This will determine what physical connectors you'll need and what your
approximate link budget will be.

Based on that information, you can figure out which type to ask for
(9um/125um single-mode, most likely), a range of path loss that you're
comfortable with, and the physical termination you'd like at either end.

Cheers,
jof

5

You Jon people[1] are, as near as I can tell, answering a question the OP didn't
actually ask. It may in fact be that he didn't realize he should spec the
design down to that level, but it sounded to me like what he was looking for
was "what language should I put in there to constrain the quality of the
implementation?"

Cheers,
-- jra
[1] :slight_smile:

6

BICSI has a sample RFQ for this purpose. You can use the whole thing or just
pull out the cabling phrase. You will need to update the standard names to
the current ones.

https://www.bicsi.org/single.aspx?l=1866

Kenneth M. Chipps Ph.D.

7

How you phrase the requirements depends on what you want the end result to be. Sorry to start this off with a wishy-washy statement, but when dealing with contractors, you have to be very specific with what you want, and stay involved during the project, to be sure the results are what you want.

It's a good idea to define very clearly what is "in scope" and "out of scope" for the contractor up front. This can include things like the contractor being responsible for submitting any one-call requests per your localities' guidelines for any work that requires digging, or restoring any items that have to be removed (landscaping, sidewalks, paved roadways, etc) to facilitate digging.

For example, do the buildings in question already have usable entrance facilities for communications (aerial/underground entrances, suitable demarc locations in each building, cable pathways from the exterior penetrations to the demarc point)? If not, you will generally need to spell out exactly what the fiber contractor (or a sub-contractor) is expected to provide (conduits from comms manhole/utility vault/pole/etc). Typically you will need to define a place in each building where the fiber will land, which will either be in a rack or on a wall.

Also, at a minimum, the contractor should 1. test all strands at the appropriate wavelengths, 2. provide you with documentation of the test results, and 3. general fit-and-finish/workmanship items such as making sure all connectors have dust caps and any required labeling of the termination bays.

Where I work, we have detailed construction / installation standards that get added to the bid package of any new construction or major renovation on our campus. If you want, I can send you a copy (off-list) of the relevant pieces of our Division 27 specs that go out to contractors as part of our construction bid packages.

jms

8

How you phrase the requirements depends on what you want the end result
to be. Sorry to start this off with a wishy-washy statement, but when
dealing with contractors, you have to be very specific with what you
want, and stay involved during the project, to be sure the results are
what you want.

This is *really* great advice. Standards are good, but it pays to have
due-diligence done about specific products and methods.

To the OP:

I witnessed a municipal fiber build-out, managed by someone in another
department who had essentially zero networking experience. His
consultants' all seemed experienced in conceptual layout, but not so much
the specific physical details. While this project was basically a success,
99% of the difficulties had to do with physical access details, site
remediation (power, racks, site-local cabling), and the specific fiber
related equipment such as splice boxes and patch panels.

For instance, we ended up with a 23" telco rack filled with 19" equipment
and 23" to 19" converter panels. General tidiness; a contractor left a
large splice-box laying on the floor in the midst of a slack-spool instead
of wall or rack mounting. Another contractor developed a spider's nest of
wiring in our server room instead of structured cabling. Specifying exact
rack sizes, specific cable management, mounting locations, etc... would
have helped a lot. Photos of the specific areas would have helped
immensely.

Some of the delivered patch panels were of low quality (many of the
connectors were faulty, requiring extra labor to clean and re-polish).
Caveat emptor! Find what the good brands are and specify (maybe others can
comment here). Go take a look at vendor websites like Middle Atlantic and
see what options are out there. Some things are just easier and more
convenient to use. The devil is in the details.

A building-to-building connection is clearly easier than lighting up a
city but you will still be stuck with what you get. You can never plan
enough.

~JasonG

9

Formal construction contract bids use the Construction Specification Institute (CSI) format. There are 2 versions, I am familiar with and use the 1998 version. The 1998 CSI format is broken up into 16 divisions (mechanical, civil, electrical, architectural, etc.). Electrical, where network cabling specs reside in the CSI 1998 version, are located in Division 16. The standard fiber optic spec is Division 16 16745. A web search on "fiber optic 16745 spec" will turn up various examples from real fiber optic construction bids, usually government contracts for large-scale construction projects such as highways, University campuses, municipal fiber builds, etc.

My suggestion is to look at existing 16745 specs, and modify them to your requirements.

10

This seems like an altogether excellent time for me to remind people about

  http://bestpractices.wikia.com

and volunteer it[1] as a place in which to capture these sorts of, among other
things, pictures of installs, both good and bad -- along with notes as to
*why* they are specifically good and/or bad.

Cheers,
-- jra
[1]Yes, it's gotten a bit spammed up; I'll clean it out if you'll use it. :wink:

11

First off, thanks to everyone who has replied, both on and off list, I've gotten some very good information on this, raising things I hadn't considered, particularly involving testing and warranties.

Daniel Seagraves wrote:
<Is it appropriate to just say "When installing fiber-optic cable the vendor will ensure the resulting installation does not suck."?>

Getting an installation that doesn't suck is indeed the core of the matter. However, "doesn't suck" is a rather vague concept as a point of law in case you have to sue your vendor for having installed something that sucks. That's why I was looking for a set of standards that I can point to and say (as an example) "your installation sucks, and it sucks because you didn't follow X standard, and ran unshielded fiber at a 90 degree angle over a knife edge."

< Maybe there should be a legal definition of the concept of suck, so that suckage could be contractually minimized.>

Unfortunately vendors install suckage all the time. Our own particular horror story was one of our schools where half the school was experiencing intermittent issues of crosstalk, lag, unexplained packet loss, etc. Some days it was fine, others it wasn't and it took us some time to find out that the cabling vendor had connected the two network closets via plain old cat 5 cable, a run that was considerably longer than 300 feet. You wouldn't normally expect to have to specify to telecommunications vendors that you don't exceed the maximum cable length, but there it was. We replaced that link with multimode, and the problems immediately vanished. I'm sure others have similar stories.

A number of people have asked for more details on the project and I deliberately didn't put those in because I was looking more for a standard that, if followed, produces acceptable link no matter what the project details are. For the curious, it's a simple point-to-point link involving an existing building and new construction that are about a mile apart . It will be singlemode, we will provide the racks on both ends, and we're specifying SC terminations. Whether we own or lease the fiber, lit or dark, depends on the economics of the quotes that come back to us. It's not a complicated project, but I shouldn't have to re-write a cabling spec as part of the RFP just to keep the vendors honest. A number of good references have been sent to me so I think I'm all set. Thanks, NANOG! :slight_smile:

---Sam