Fiber Optic Cabling

[Billprozac]

Ok, I am new to building to building fiber optics, so I need some help.

In addition to our main location, we operate three buildings which are all next to each other. We currently used a piece-work wireless system to connect the three. I am going to run fiber between the three buildings but am new to this type of fiber.

Our contractor has put conduit inplace. The runs are 500ft and 450ft. One location has a switch with two fiber GBIC 1000B-SX. The other locations have switches with 1000B-SX connectors. I know I could get really long "patch cables" to go between thebuildings, but I want to do this right. What cable should I get? Patchpanels? I see multistrand multimode. I need a little clarification. I assume 6 strand cable simply has six fibers (3 pairs) and because of the short distance, multimode would be best. Any thoughts/recommendations?

[D1g1talMan]

I haven't done too much of that myself either, but I know we use Corning patch panels and 6 strand multimode fiber between our buildings.

With runs of only 500 feet, you won't have to worry about distance. Multimode can run about 2km before you need to boost the signal.

[D1g1talMan]

I guess I should add a bit more to that previous post.

I'm not sure what your bandwith or user requirements are between buildings. Here, we go for overkill, so 300 people in each building (or so) with about 600 machines in each. (we're a development enviroment.) We have a Cisco 4500 series switch in each, with Supervisor Engine IVs. We ran a 6 strand multimode between the two, for 3 connections. A patch panel on each end terminates the run, and from there, we use your generic fiber patch cable to plug from the panel to the GBICs on the Supervisor Engines. since the Cisco switches can load balance between the connections, that's about 3 Gbps full-duplex between the two. You might be able to get away with less, in which case, get a cable with a single pair. We run full gig-E to each workstation, so we usually double or triple our cross connects.

It's really not too different in concept than copper ethernet, just with different equiptment. Fiber is definitally a big improvement over a wireless cross-connect (I'm surprised it worked reliabily at all!) but you might want to spend some time analyzing your bandwith requirements. If you're running 10/100 to your workstations and your demands are not too high, then you might get away with a single pair of fiber connecting your two buildings, though now that I think about it, having a failover might be worth the extra investment.

[Billprozac]

That's kind of what I was thinking. The needs are very limited, which is why wireless was "working". One location has three users, one has one, and the other will have two at most. We are going to be runnin gip based security, however, which necesitates the bandwidth (multiple video cameras).

I was thinking of six strand so I could mesh the buldings for failover. I guess I could use four, but I like the idea of having an available pair for future needs.

The fiber will patch to switches located at each location and one location has a t1 point-to-point coming back to the main building. by the way, we are a museum, hence the limited staff but high security needs and willingness to use wireless to save money ;)

[cosign9114]

Always best to have a back-up. Especially if the fibre is getting laid and then having things put around it, like where I work (a school) we have the fibre running under the ground to the PE Block, and we thought it had gone down the other day as the phone's (Voice over IP) weren't working, switched the fibre over with the data side and then the phones worked and the data didn't luckily it was simply that one of the connecters was dirty and so it was giving a signal sometimes and not others and so the system was screwing up! But we have the same thing, we have 2 x 2 core fibres, on first fibre we have one core being used for data and one core being used for phones, and the second fibre is a spare incase one goes down, because I wouldn't fancy having to dig the fibre up to replace it :)

[transplant]

From the wording of your question, it sounds like this is going to be a DIY fiber run. The following response is based on that assumption.

I would highly recommend you hire an outside contractor to make the fiber optic runs between your buildings. Working with fiber is not like Cat-5, where anyone with enough tips will eventually make a good run. Here's the main reasons:

1. Fiber is expensive. If you get a kink while pulling it through the conduit, you're going to need to re-run it (no easy splicing solution). Standard ST or SC tips will run you a dollar or two each.

2. Fiber tools are expensive. Expect to pay between $500-$5000 on a good fiber toolkit, plus extra for supplies like epoxy, polishing paper, etc. (1 um Diamond-grain polishing paper runs $10 a sheet!)

3. Fiber takes training to install and tip properly. For long runs, you're going to need to make sure you use the correct type of fiber for the fire codes in your building (plenum, riser, etc.). Since this will obviously be a long-term solution, you're going to want to probably use an epoxy-based tipping solution for maximum durability. Being able to properly tip something like this takes practice and training.

Based on those points, it's going to be much easier (and probably less expensive) to just hire a qualified contractor to do the work for you. Look for someone who's ETA FOI (Fiber Optic Installer) certified, at a minimum.

To answer your question - yes, I'd recommend 6-strand multimode fiber for the conduit run. It's always a good idea to keep an extra couple of strands available for failover, and the price difference between 4 and 6 strand is negligible.

[Billprozac]

The fiber run is simply building to building, there will be no fiber in the plenum or rated areas of the buildings unless it is in conduit. I was not planning on doing any of the termination. Since we have an electricion coming out to finish the conduit an dpullstring, he offered to pull the fiber through. THis would save quit a bit of time and money.

My plan is to go with 6-strand Multimode outdoor cable leaving a spare pair on each run. How firm is the distance limitaion of 62.5/125? I have seen 220m listed as a max, but some have said 100' would be fine. 720' != 100'

or for you VB guys

720' <> 100'

[transplant]

Check the last paragraph in this link for details on multimode fiber lengths. The short answer is, distance will be measured in hundreds of meters, not one hundred feet. If your building-to-building distance is under 200 meters, you'll definitely have no problem.

Oh, and good job on getting the electrician to pull the fiber for you. That will certainly save you some cash.