What Makes Fiber Optic Cables Better Than Copper Cables?

AntonioCrocombe

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#1
There are few things in my mind, which is the best fiber optic cable or copper cable. I need help for the clear about this point. which is the better and faster connectivity cable?
 

Chewy509

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#2
Depends on your budget, skill set and product availability...

For raw performance, fibre optics performs better (we are deploying 10Gb ethernet via fibre at work for all workstations), but it's more expensive to setup. (switches, NICs, etc are more expensive). 40Gb and 100Gb ethernet products are available.

Copper is cheapr, 1Gb Ethernet products are very cheap to acquire/install, etc. Also copper is easier to work with. 10Gb and 40Gb copper based ethernet products do exist, but are relative rare and expensive. (40Gb copper is limited to 30m total cable length as well). There are 100Gb copper based ethernet products defined (and available) but from experience, pretty much most people who are deploying 100Gb ethernet products are using fibre.
 

CougTek

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#3
Length of cables will also affect what's best for you. also, there're two kind of copper cables for +10Gbps connections: 10Gbase-T and DAC cables. 10Gbase-T is your standard NTP cable with an RJ45 connector. Depending on the wire standard, you can connect devices up to 37m to 100m with those.

DAC cables (Direct-Attach Connect) are intended to connect devices within the same rack or adjacent racks in the same room. You won't go farther than 10m using DAC cables.

Optical fibre can connect devices up to 80Km when using proper transceivers and single mode fibre. Multimode fibre will connect devices at 10Gbps or above at length up to 330m IIRC. There are many variables and standards, but generally speaking, regarding length of connections: fibre->RJ45->DAC.

Latency is another major differenciator. Fibre transceivers have a latency of ~0.5µs, while 10Gbase-T is around 2.6µs. DAC is between both, at a little over 1µs.

Finally, there's the power per port. 10Gbase-T consumes significantly more juice per port than DAC cables and also often more than fibre transceivers, although the latter isn't true regarding long-distance (+10Km) transceivers. Within a datacenter and assuming multimode fibre, power consumption looks like this: 10Gbase-T->optic transceiver->DAC cables.

There's a lot more choice of switches with SFP+ ports than 10Gbase-T ports.
 

Lena

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#4
Length of cables will also affect what's best for you. also, there're two kind of copper cables for +10Gbps connections: 10Gbase-T and DAC cables. 10Gbase-T is your standard NTP cable with an RJ45 connector. Depending on the wire standard, you can connect devices up to 37m to 100m with those.

DAC cables (Direct-Attach Connect) are intended to connect devices within the same rack or adjacent racks in the same room. You won't go farther than 10m using DAC cables.

Optical fibre can connect devices up to 80Km when using proper transceivers and single mode fibre. Multimode fibre will connect devices at 10Gbps or above at length up to 330m IIRC. There are many variables and standards, but generally speaking, regarding length of connections: fibre->RJ45->DAC.

Latency is another major differenciator. Fibre transceivers have a latency of ~0.5µs, while 10Gbase-T is around 2.6µs. DAC is between both, at a little over 1µs.

Finally, there's the power per port. 10Gbase-T consumes significantly more juice per port than DAC cables and also often more than fibre transceivers, although the latter isn't true regarding long-distance (+10Km) transceivers. Within a datacenter and assuming multimode fibre, power consumption looks like this: 10Gbase-T->optic transceiver->DAC cables.

There's a lot more choice of switches with SFP+ ports than 10Gbase-T ports.
What is the better option between the two copper cables that you mentioned?
 

Handruin

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#5
What is the better option between the two copper cables that you mentioned?
Like anything it depends on your budget and use case. RJ45 copper is more susceptible to alien cross-talk which can reduce performance in noisy environments but it's more ubiquitous and can cost the least. DAC can reject alien cross-talk better and support higher performance in noisier environments but will be limited in distance and they often cost a lot more than RJ45. You also will need a switch which supports SFP+ connections if you aren't direct-connecting which those tend to cost a lot because they're 10Gb.
 

Lena

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#6
Like anything it depends on your budget and use case. RJ45 copper is more susceptible to alien cross-talk which can reduce performance in noisy environments but it's more ubiquitous and can cost the least. DAC can reject alien cross-talk better and support higher performance in noisier environments but will be limited in distance and they often cost a lot more than RJ45. You also will need a switch which supports SFP+ connections if you aren't direct-connecting which those tend to cost a lot because they're 10Gb.
Thanks for the clarification mate. I will look up online how much a a switch which supports SFP+ connections costs.
 

Lena

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#7
Like anything it depends on your budget and use case. RJ45 copper is more susceptible to alien cross-talk which can reduce performance in noisy environments but it's more ubiquitous and can cost the least. DAC can reject alien cross-talk better and support higher performance in noisier environments but will be limited in distance and they often cost a lot more than RJ45. You also will need a switch which supports SFP+ connections if you aren't direct-connecting which those tend to cost a lot because they're 10Gb.
Or would you be having an idea what price range the switches are in?...i don't want to land on an overpriced site.
 

mangyDOG

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#9
I have just installed one of these: https://www.ubnt.com/unifi-switching/unifi-switch-16-xg/ in my office. They are less than $1k here in Aus which is pretty good for a 16port 10G switch. It gives you 12 SFP+ ports and 4 RJ45 ports. The Ubiquiti fibre transceivers are also very well priced and are sold in pairs. A pair plus an OM4 LC-LC fibre patch lead is quite a bit less than a DAC cable. The transceivers also work well with other brands, on my setup I have a Ubiquiti unit in the switch connecting to a NAS which is using an Intel X520DA2 card with Intel transceivers.
 
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