Fiber Between Buildings

[tbutler@ofb.biz]

Given the saga of my 260 ft ethernet run in my previous thread, I'm seriously considering dumping the ethernet run and putting in fiber between the buildings. I've seen mixed mode fiber cabling that length for about $100, which means the project wouldn't cost THAT much, and I'd also be able to stop worrying about the need for surge protectors on the ends of the cable that runs through the conduit.

I've searched a good deal about fiber, but most of the information I've found has assumed the reader has a lot more experience with fiber than I have had (i.e. none). Is there a good resource for a basic tutorial on fiber? Basically, I could use some advice on which sort of connectors are best out of the variety that seem to exist, how to crimp those connectors on and what media converters are best to convert from fiber back to copper on each end.

Does anyone either have pointers on these subjects or suggested online resources that have how-to's on this?

Thanks!

Tim

 

[thiggins]

I would buy pre-terminated cable if you can. Terminating fiber still isn't easy. Hell, I have enough trouble terminating RJ-45 plugs! Have you seen this?
http://www.lanshack.com/fiber-optic-tutorial.aspx

If the whole switch to fiber seems daunting, there are always copper-based Ethernet extenders.
http://www.ethernetextender.com/ethernet-extension-products/ethernet-extension-kits/828.php

 

[tbutler@ofb.biz]

Thanks, Tim, that looks like a helpful tutorial. I've heard mixed reviews on whether one can pull it or one needs to push it through conduit. It looks like the LANshack tutorial suggests it can be pulled, so that's reassuring. I know what you mean about terminating RJ-45 connections. I've gotten a lot better at it than I was, but making terminations more complicated doesn't sound like much fun.

If I can just figure out why my ethernet surge protectors are causing significant packet loss on the long run, maybe I'll stick with copper...

 

[Terry Kennedy]

I've searched a good deal about fiber, but most of the information I've found has assumed the reader has a lot more experience with fiber than I have had (i.e. none). Is there a good resource for a basic tutorial on fiber? Basically, I could use some advice on which sort of connectors are best out of the variety that seem to exist, how to crimp those connectors on and what media converters are best to convert from fiber back to copper on each end.

Does anyone either have pointers on these subjects or suggested online resources that have how-to's on this?

Fiber is definitely the way to go if you have the budget for it. There are "indoor" grades of fiber as well as "outdoor" ones. Even with your wet conduit, you could go with indoor grade, which will save you some money as well as potential hassles with flammable fillers in the outdoor grade cable.

If there's other stuff in the conduit or you anticipate other things going in later, you may want to use a cable with more than the usual "zip cord" level of protection. You can get 2 or 4 fibers in a more robust jacket.

Your choices are single-mode or multimode. There used to be a huge cost advantage for multimode, but they're pretty even these days, unless you're buying stuff from a company like Cisco at list price.

I agree that you'll want pre-terminated cables. I've been terminating my own fiber cables for decades, but I wouldn't recommend it for a beginner. And these days you can buy complete imported patch cords for less than the cost of a single connector. Probably the 2 most common for your application are SC and LC. SC is 2 individual square connectors, while LC is more like a CAT 5 plug, but with 2 fibers. Which one you use probably depends on what connectors your equipment will have (otherwise you'll need patch cords as adapters).

When ordering the cable, make sure you get one with at least one end protected so it can be pulled through the conduit without damaging the connectors. This can range from simple electrical tape all the way through re-usable "chinese fingers".

For equipment on the ends, I'd suggest switches with at least one SFP port. That way you can run the fiber directly into the switch and use whatever management the switch gives you to monitor things. SFP is an industry standard for a plug-in transceiver (usually Ethernet, mostly fiber). That will use LC connectors. The SFP's can be found on eBay for under $10 each - the big cost will be in getting switches that have SFP ports. Something like the Netgear GS110T (8 copper 10/100/1000 + 2 SFP) should work.

The other alternative would be standalone media converters (fiber to copper). The problem is that these aren't manufactured in the same volume as switches, so you'll likely end up spending more for less functionality - your switch will be looking at the copper link to the media converter instead of directly at the fiber, so it won't see problems on the fiber side of the media converter.

 

[matthelm]

...
If I can just figure out why my ethernet surge protectors are causing significant packet loss on the long run, maybe I'll stick with copper...

First, they are Gigabit rated??? Second, just guessing, but I bet you have a ground loop. Yes, this can happen between buildings, even with good grounds, which most do NOT have.

Fiber would fix more than that. It would also isolate the 2 building 100% electrically, which would be safer in the long run anyway.

 

[tbutler@ofb.biz]

Thanks Terry and matthelm! I appreciate all of the tips. If I go the fiber route (and I'm increasingly leaning that way), do you have recommendations on where to go for a good deal on pre-terminated cables close to 100m in length? I ordered two SFP capable switches from Newegg on sale to give this a try. As I think I mentioned earlier, I saw one on Amazon for right at $100, but it didn't come with any sort of protective cover on one end. I presume the cover also is designed so that one doesn't stress the delicate fiber when pulling, but rather the inner support string/fiber/etc.?

 

[kanewolf]

Since you have SFP capable switches, you should choose LC to LC fiber. I would recommend 50 micron (not 62.5) and for a few $$ more get the 10 gig rated (teal color) fiber. Just looking around on the internet I see http://www.fibercablesdirect.com -- the prices seem similar to what I have gotten LC cables for at work. A 35 meter LC to LC 10 gig rated cable is about $75. A few feet extra can be coiled into a 1 foot diameter coil with not loss of signal. Don't coil TOO small -- you could exceed the minimum bend radius of the fiber which will cause loss of signal. Try to have some type of support for the fiber at the switches. Again the weight of the cable can cause a pretty severe bend. 4 to 6 inch radius bends are perfect.

You should be able to use your existing copper cable as a pull-string. LC connectors have dust covers to protect the fiber itself and a small amount of bubble plastic wrapped around the end should be all that is required. (I didn't see what size conduit you are pulling through.) A little electrical tape holding about a foot of overlap between the copper and fiber should be plenty. UNROLL the entire length of the fiber so that it won't be twisted as it is pulled through. Pull a new pull-string (either purpose made pull-string or masons string) in parallel with the fiber so that if anything else needs to be pulled you can do so. This is not a single person job. You need someone feeding and someone pulling.

 

[Terry Kennedy]

Just looking around on the internet I see http://www.fibercablesdirect.com -- the prices seem similar to what I have gotten LC cables for at work. A 35 meter LC to LC 10 gig rated cable is about $75.

Assuming you're referring to http://www.fibercablesdirect.com/products/-/110, this is the "zip cord" type I was referring to earlier as not optimal. It doesn't provide a lot of protection, either when pulling it in or when it is in use and somebody else pulls something additional through the conduit. You don't need to go for a full armored cable, but something with some additional protection would be good. Otherwise you may have an outage at an inconvenient time. A quick search turned up this (for some reason that site takes incredibly long to load, give it a few minutes), which is a somewhat more rugged indoor/outdoor cable. 100' prices at $116.20, or $136.20 with a pulling eye at one end. I don't have any experience with that company, I just found them via a web search.

Don't forget that you'll need matching SFP's. Technically you need mode-conditioning cables for longer multimode runs, but you can usually get away with just plugging the multimode cable in. On the other hand, that same web site shows far more choices in duplex single-mode cables.

 

[tbutler@ofb.biz]

Thanks for all of the advice, Terry and Kanewolf! I'm going to keep this in mind if I have to run fiber.