Connecting two buildings

Aug 01, 2006 6 Replies

Hi,



I'm making a plan to connect two buildings over Ethernet that are at least



500 feet apart. I'm thinking of using fiber optic cable because of the distance. I think I want multimode fiber with sc/sc connectors. I'm not sure if the network I'm upgrading has gigabit Ethernet fiber optic support, so I want to use two TRENDnet 1000BASE-T to 1000BASE-SX Fiber media converters at either end. Furthermore, I want to run the fiber optic cable through a tube in the ground.

Is this a good plan or should I try something different?



Thanks,



Jared


Jared Perkins wrote in part:

This sounds generally good. Conduit is a good idea -- leave a pullstring and some unterminated fibers. There is often a problem lwith water ingress, so the cable should be rated for direct burial.

How much bandwidth you need will depend on that traffic. If the servers are in one building, and users in another, then you may need all the bandwidth you can muster.

-- Robert

To me it sounds reasonable for present equipment.

Looking ahead, I see that 10 gigabit (10000Base-SX) is only supported at those distances for 50 micron fibre, and under fairly specific technical conditions -- 86 metres max for the regular conditions, and only about 100 feet for 62.5 micron fibre. 10000Base-SX is not supported on SMF it appears.

It appears that that distance is practical for 10000Base-LX (WWDM) over all the regular types of MMF.

Hence, that fibre should be okay, but if you do switch to 10 gigabit at some point, you will have to go into LX rather than SX, unless you want to fit now to the tight specs for 10000Base-SX over longer distances.

[Okay, so it probably won't, but once I'd looked up the information, I might as well post it so others don't chase the same details ;-) ]

Make sure you use schedule 80 PVC for your underground conduit.

Also, the fiber if multimode make sure your use 50/125 fiber. If you plan ever to use multigigabit (like 10GbaseT) you need 50/125, 62.5/125 fiber wont cut it. Singlemode is probably your safest bet though, but 50/125 will work.

Perkowski

My research indicated distinctly otherwise; see my reply.

I was pulling the information from ieee.org itself.

Yep u right for the 50/125.

Singlemode is the way to go though

I think single mode is definitely the way to go for 10G, for distances beyond a couple hundred meters. One table that tells the story is Table

52-24 in IEEE 802.3-2005.

The other possibility, for any sort of distance, is the 4-lane method,

10GBASE-LX4, which has both singlemode and multimode options. The problem is, I believe very few vendors are actually implementing this. With 50/125, in theory, the 4-lane option can get you up to 300 meters.

Bert

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required