Fibre Bandwidth question?

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IntelOwnz

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Oct 29, 2006
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So I have a small amount of spare fibre cable, I thought this stuff was worth alot, but it's pretty cheap!

Question though, I found some cheap fibre nics that only do gigabit, and the more expensive ones do 2gbps

Here's the question, why would someone want to use fibre to do gigabit when they can use cat5e/6 and save a bit of money? I think I'm missing something here, please fill me in.
 
IntelOwnz said:
So I have a small amount of spare fibre cable, I thought this stuff was worth alot, but it's pretty cheap!
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The cable itself isn't too bad, you are right. When you start talking about the connectors, NICs, switches, routers and such is where the expense starts to come into play. Furthermore is the cost of repair. If fiber breaks, it is alot more costly to repair. Not only for the repair itself, but for the skill level required (A pro).

Here's the question, why would someone want to use fibre to do gigabit when they can use cat5e/6 and save a bit of money? I think I'm missing something here, please fill me in.
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Depends what fiber you are using. Cat5e is not Gigabit. Copper standards have to be totally redone for the most part when you want an upgrade in speed. Fiber, on the other hand, the only thing that really changes with it is the transmitting and receiving nodes. Light passing through glass will always be the same thing... The NICs transmitting, with new technologies and angles of light it uses, is what changes.
 
zacdl said:
The cable itself isn't too bad, you are right. When you start talking about the connectors, NICs, switches, routers and such is where the expense starts to come into play. Furthermore is the cost of repair. If fiber breaks, it is alot more costly to repair. Not only for the repair itself, but for the skill level required (A pro).


Depends what fiber you are using. Cat5e is not Gigabit. Copper standards have to be totally redone for the most part when you want an upgrade in speed. Fiber, on the other hand, the only thing that really changes with it is the transmitting and receiving nodes. Light passing through glass will always be the same thing... The NICs transmitting, with new technologies and angles of light it uses, is what changes.
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Category 5 cable may be able to run Gigabit Ethernet, but Category 5E is recommended (for gigabit).
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I guess Cat5e can do gigabit speed. So again, why would someone use fibre just to do gigabit speed. Unless you are going up in speed (ex. 2gbps) why would one use fibre? Of coarse it may be cheaper if you were running lots of cabling, but I am simply going from one pc to another.

Can you use fibre like a cross-over cable?
 
Technically, yes. It is not done very often though.

Cat5e cannot be run very far without having to use a switch or something- and Gigabit switches are pricey. Crosstalk with Gigabit on Cat5e is also a problem... hence why Cat6 came out (all Cat6 really has is more twists to solve the Crosstalk issue). But again, the distance requirement knocks out a bunch of applications for it.

Generally the places you need Gigabit are backbone segments between servers, the sort of stuff that has longer runs of cable. Cat5e/6 just can't go very far.
Fiber on the other hand can be run for miles (depending what kind) without needing anything inbetween.

Edit- Fiber can be run directly from PC to PC, yes. There is no such thing as a crossover cable though- its just a signal of light, you don't cross any pairs of copper connectors to get it to work. If you have the stuff, go ahead and use fiber if you feel you must tinker :) But unless you have very fast hard drives and such- its not going to help you much at all.
 
zacdl said:
Technically, yes. It is not done very often though.

Cat5e cannot be run very far without having to use a switch or something- and Gigabit switches are pricey. Crosstalk with Gigabit on Cat5e is also a problem... hence why Cat6 came out (all Cat6 really has is more twists to solve the Crosstalk issue). But again, the distance requirement knocks out a bunch of applications for it.

Generally the places you need Gigabit are backbone segments between servers, the sort of stuff that has longer runs of cable. Cat5e/6 just can't go very far.
Fiber on the other hand can be run for miles (depending what kind) without needing anything inbetween.

Edit- Fiber can be run directly from PC to PC, yes. There is no such thing as a crossover cable though- its just a signal of light, you don't cross any pairs of copper connectors to get it to work. If you have the stuff, go ahead and use fiber if you feel you must tinker :) But unless you have very fast hard drives and such- its not going to help you much at all.
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I'm just doing some learning/experimenting. Probably won't buy either, it's just good to know. Would you know of any good resources online for networking/server info? I tried looking but there's no real good sites that I can find. This forum seems to be my best solution.
 
Get a book?
You know how big the field of "networking/servers" are? You could read 2' thick of books and still have plenty leftover to read :) Plus most of it comes from just doing it, making mistakes, and learning from them.

I don't know of any websites right off... all I can tell you is either get a basic degree in Network Engineering or perhaps read some books... and then you will have a basic understanding!
 
I'll answer the question "why would someone use fiber instead of copper".

Bought my house 2 years ago. Unfortunately it was already built when I found this house so I did not get a chance to run conduit and run as much cable as I want. I was in a dilemna when I realized while I was drilling holes that I couldn't fit 36 cables thru a 2" hole from the 2nd floor to the ground floor. Since I had 4 x 200 meters of fiber "laying around" I created an IDF downstairs. Easier to run 4 fibers than 36 cat6 cables from the attic to the crawl space. So the setup is 48-port 3750G upstairs with 4 1XGb links etherchannel'd to another 3750G 48-port downstairs. Overkill? Maybe but as a geek the thought that I've outdone my brother-in-law who run cat6 all over his house is priceless.
 
In most bigger cities, the newer homes are all being wired up with fiber now. I know someone up in Portland- his house doesn't have any cable, nor any phone lines. All fiber. The TV is cheaper than cable lines. The internet is super fast, plus also very cheap.
Once implemented- fiber is very easy to upgrade or change as needed... thus why the initial cost is higher- but the long term cost is actually lower.
 
unix_foo said:
I'll answer the question "why would someone use fiber instead of copper".

Bought my house 2 years ago. Unfortunately it was already built when I found this house so I did not get a chance to run conduit and run as much cable as I want. I was in a dilemna when I realized while I was drilling holes that I couldn't fit 36 cables thru a 2" hole from the 2nd floor to the ground floor. Since I had 4 x 200 meters of fiber "laying around" I created an IDF downstairs. Easier to run 4 fibers than 36 cat6 cables from the attic to the crawl space. So the setup is 48-port 3750G upstairs with 4 1XGb links etherchannel'd to another 3750G 48-port downstairs. Overkill? Maybe but as a geek the thought that I've outdone my brother-in-law who run cat6 all over his house is priceless.
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Priceless ;)


I suppose Fiber is a good initial investment, unfortunetly in a company my size, we are not looking at long term investments, we need to stay afloat here matey!
 
Jeezus, I wish my home networking budget let me use a couple 3750's....

But I bet the time spent and frustration levels of fishing all that cable alone would steer me towards that type of solution... ;)
 
Fiber is 1pair straight through. Just swap the Tx and Rx to get an x-over.
 
IntelOwnz said:
So I have a small amount of spare fibre cable, I thought this stuff was worth alot, but it's pretty cheap!

Question though, I found some cheap fibre nics that only do gigabit, and the more expensive ones do 2gbps

Here's the question, why would someone want to use fibre to do gigabit when they can use cat5e/6 and save a bit of money? I think I'm missing something here, please fill me in.
Click to expand...

Why use fiber?

For a number of situations...

1) Fiber is impervious to EMI. No more worries about crossing A/C Lines at right angles and staying at least a foot away from Flourenscent lights, etc...

2) Fiber typically has a longer max transmission distance. The Cat5/Cat6 spec maxes out @ ~300ft (100m). Most basic fiber transceivers can do 1000' easy.

3) VERY diffucult to tap a Fiber line on-the-fly w/o breaking it.


Side note, the NICs that you said you say that'll do 2Gbps, are most likely GBIC's for a fibrechannel switch/array and not for standard networking. Look a little closer at them...
 
Nate7311 said:
Side note, the NICs that you said you say that'll do 2Gbps, are most likely GBIC's for a fibrechannel switch/array and not for standard networking. Look a little closer at them...
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bingo, i was going to point that out...

your only going to find gige fiber nics (or if you have cash to light on fire 10GigE hehe)
 
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