nanog mailing list archives

RE: Cable standards question


From: "Sam (Walter) Gailey" <gaileywg () MANSFIELDCT ORG>
Date: Mon, 14 Nov 2011 22:07:17 +0000

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! :)

---Sam 



-----Original Message-----
From: Daniel Seagraves [mailto:dseagrav () humancapitaldev com] 
Sent: Monday, November 14, 2011 9:58 AM
To: nanog () nanog org
Subject: Re: Cable standards question


On Nov 14, 2011, at 8:42 AM, Sam (Walter) Gailey wrote:

"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.

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.




Current thread: