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If the switching hub is in the floor above the server, I've heard its best to use fibre-optic cabling to avoid interference from unrelated electrical cabling in the ceiling for lights etc...

Is it common for a rack-mount server to have fiber-optic input and output from router and to the switch? Is there some kind of mediation device that converts it from cat5 to fiber-optics?

  • This question is missing too much information that's specific to your deployment, and is too open-ended/poorly scoped. Consider editing your question when you have more information. These details are usually missing because they're going to be dependent on the environment or the design specs. – John Jensen May 28 '13 at 19:15
  • the floor bellow also has a switching cupboard, i think with all the information Ive got it seems that the switching cupboards should be connected via fibre optics and then that should be converted by a top of rack switch on each floor. Does that sound right? – Max Carroll May 28 '13 at 19:52
  • It could sound right. You can edit your question to include this information - this is useful and encouraged. @bigmstone's answer is a good one. – John Jensen May 28 '13 at 20:29
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SFP style input is really only common for 10Gig and beyond applications. You can get 1G SFP PCI cards for your servers but I think this would become very expensive when compared to a top of rack switch solution.

This sounds like a small business setup. From that perspective I would say that as long as the servers are < 100M from the switch and the cable doesn't directly go over florescent lights or something else that could create interference then you should be fine. If that's not the case and your servers are aggregated at 1Gb then I would recommend running fiber to a top of rack switch and using standard Ethernet to aggregate the servers.

On a final note I rarely see actual fiber optics going into a server. It's typically TWINAX if it's SFP based or CAT-5e or CAT-6.

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    SFP's originally only went up to 1G. SFP+ is for 10G and higher; fiber NIC's with SFP PHY's aren't that uncommon, but they're definitely pricier when compared to onboard copper. – John Jensen May 28 '13 at 19:17
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    @JohnJensen yeah, that's why I said "SFP style." Didn't want to confuse anyone by starting to talk about QSFP, SFP+, and SFP. – bigmstone May 28 '13 at 19:40
  • Ah ha, so you did. Shame on me for poor reading comprehension! – John Jensen May 28 '13 at 19:41
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The question of using fiber vs copper for an uplink is commonly answered by distance (or as you pointed out - environmental) requirements.

It's hard to say whether or not a server "usually" provides copper or fiber connectivity - this all depends on the NIC installed. Usually, servers are connected to a Top of Rack switching solution, which usually means copper (Cat6) cabling is perfectly fine. Those switches can then be connected to some kind of distribution layer or core via fiber, but again, depending on requirements, this can be Cat6 as well.

If you feel that there are environmental or distance concerns where copper may not yield the best results, then use fiber. However, for short distance, copper connectivity is usually just fine.

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Servers still predominantly come with 1000Base-T interfaces but SFP cages are starting to appear with very new kit. You can also buy SFP NICs for your servers if they don't have them already. Otherwise, use a top-of-rack switch to convert from fibre to copper. Stay away from media converters, they are either no cheaper than a switch or very limited in functionality (jumbo frames!)

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  • i think top-of-rack switch is a good idea thanks for your input – Max Carroll May 28 '13 at 19:30
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It's more common in larger servers or in blade chassis setups. That said, there's not much stopping you from going out and buying a fiber nic to install in the server.

That said, take a step back and look at your justification/reasoning for doing this. If you're going to have a stack of servers a floor away from your switching area, running an individual cable for each of those servers is going to open up the opportunity for all kinds of problems in the future. The "standard" option here is to put a switch at the top of the rack containing your servers, which will also solve your copper vs fiber issue, and run a single/pair of connections back to the switching area.

If you're doing a one-off server, why is it being installed a floor away from the switching equipment?

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  • This has really made me think, thankyou. Im actually going to have computers on both floors, so maybe i will have a switch cupboard downstairs with the server in, then a top of rack switch convert to take it upstairs, then another top of switch convert in the upstairs to change it back for the switch cupboard, does that sound pheasable? – Max Carroll May 28 '13 at 19:29
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Is there some kind of mediation device that converts it from cat5 to fiber-optics?

If you want to convert between fibre and copper you can use a media converter such as these;

http://www.tp-link.com/en/products/?categoryid=225

http://global.level1.com/Media-Converter/Unmanaged/2-16-73.htm#2

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