Internet facts and myths

[poddster]

FACT

1. Internet data flow speed is limited to the speed of the slowest link between source to destination, regardless of the transport medium used.

(Be that copper, optic fibre, wireless or even wet string)

MYTH

Propagation of signal using Optic Fibre is faster than propagation of signal using copper.

(Propagation in both mediums is 66% plus or minus 5% of the speed of light in a vacuum)

[flashie*]

FACT............6-1x0+2/2=7......:-D

[the_hawk*]

FACT

1. Internet data flow speed is limited to the speed of the slowest link between source to destination, regardless of the transport medium used.

(Be that copper, optic fibre, wireless or even wet string)

MYTH

Propagation of signal using Optic Fibre is faster than propagation of signal using copper.

(Propagation in both mediums is 66% plus or minus 5% of the speed of light in a vacuum)

Point 1 I agree with

Point 2 while electricity travels at around 66% of the speed light data does not due to a number of reasons.

first the data needs to be requested, then sent, then a check some to varify the data received is the same as was sent.

This slows the data flow dramatically, then comes the issue of noise on the copper wire that requires multiple requests for the data to be resent until the check sum matches.

But I am sure you already knew all of that

[lionrose.7]

I have fibre optic, seems fast to me.

Hi Hawk 🙂

[donnashuggy]

FACT 3

The coalitions policy is a dud.

[cherry*135]

FACT:

When we're talking about 'speed' were actually talking about throughput (or capacity) — the amount of data you can transfer per unit time, says Associate Professor Robert Malaney from the University of New South Wales, School of Electrical Engineering and Telecommunications.

And fibre optics can definitely transfer more data at higher throughput over longer distances than copper wire. For example, a local area network using modern copper lines can carry 3000 telephone calls all at once, while a similar system using fibre optics can carry over 31,000.

So what gives it the technical edge over copper wires?

Traditional copper wires transmit electrical currents, while fibre optic technology sends pulses of light generated by a light emitting diode or laser along optical fibres.

"In both cases you're detecting changes in energy, and that's how you encode data.

"With copper wires you're looking at changes in the electromagnetic field, the intensity of that field and perhaps the phase of the wave being sent down a wire.

"With fibre optics, a transmitter converts electronic information into pulses of light — a pulse equates to a one, while no pulse is zero. When the signal reaches the other end, an optical receiver converts the light signal back into electronic information," explains Malaney.

The throughput of the data is determined by the frequency range that a cable will carry — the higher the frequency range, the greater the bandwidth and the more data that can be put through per unit time.

And this is the key difference — fibre optic cables have much higher bandwidths than copper cables.

"Optical fibre can carry much higher frequency ranges — note that light is a very high frequency signal — while copper wire attenuates or loses signal strength at higher frequencies," says Malaney.

Also, fibre optic technology is far less susceptible to noise and electromagnetic interference than electricity along a copper wire.

"You can send the signal for over 200 kilometres without any real loss of quality while a copper cable signal suffers a lot of degradation over that distance," says Malaney.

[catsnknots]

so Poddy.. please tell me... no one else can... 

Some parts are getting NBN here... in fact the first part of the NBN is under construction. Apparently it is a new estate... in fact 2 new estates... 

BUT.. I don't get the hype.. 

I looked at the line back to Brisbane and most of the NBN is missing still.. 

The first bit being built is seaside... there is no connecting fibre to anywhere... so what is the benefit??? 

All over the news is that Bundaberg starts construction in the next week or two... or something like that... BUT there is no fiber out to the rest of the country so why are they starting here??? 

How is it going to make anyone go faster when there is a 100 lane hwy that is going to connect to a two lane hwy??? 

[cherry*135]

AProf Rob Malaney :

It important not to confuse 'speed' with the 'throughput' of data - i.e. the amount of data transferred per time bin (units bits/s). Throughput is the key metric that we need to focus on. The 'speed' of information (e.g. how fast a bit can propagate along a cable) is for all intents and purposes the speed of light (it is actually a little slower) - and is not an important issue when we are discussing the pros and cons of fibre versus copper.

The wavelength of the light makes no difference to the throughput by itself. But if we use, say two different wavelengths of light, we can double the throughput. Think of wavelength multiplexing as being a pragmatic way of utilizing all of the frequency range allowed by a fibre.

The throughput of a specific length of the fibre will ultimately be bounded by the range of frequencies it can carry over that length. Of course how fast you can modulate, or encode, the signal (e.g. switch it on/off) before you send it out for transport can ultimately have an impact- but again this is latter point not an important issue when we are discussing the pros and cons of fibre versus copper.

[poddster]

Hawk,

first the data needs to be requested, then sent, then a check some to varify the data received is the same as was sent.

This slows the data flow dramatically, then comes the issue of noise on the copper wire that requires multiple requests for the data to be resent until the check sum matches.

Your statement applies to BOTH optic fibre and copper as far as data acquisition and verification is concerned.

But thank you for acknowledging that indeed optic fibre and copper have identical propagation.

[the_hawk*]

Hawk,

first the data needs to be requested, then sent, then a check some to varify the data received is the same as was sent.

This slows the data flow dramatically, then comes the issue of noise on the copper wire that requires multiple requests for the data to be resent until the check sum matches.

Your statement applies to BOTH optic fibre and copper as far as data acquisition and verification is concerned.

But thank you for acknowledging that indeed optic fibre and copper have identical propagation.

They don't have the same properties at all,

The optic will not suffer from noise interference, has much higher bandwidth and much lower attenuation, making it possible for far higher speeds and distances.

not to mention much greater ability to supply possible future demands