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Standard User ft247
(member) Sun 02-May-21 14:43:36
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Re: The road to full fibre...


[re: j0hn83] [link to this post]
 
I can see why Openreach have gone for GPON rather than XGS-PON, there must be a significant cost saving in the massive quantities they're buying and the average customer will be perfectly happy with GPON. Yes, there may be some commercial areas where XGS makes sense sooner rather than later.

Given 30% annual growth in demand GPON is easily good for the next ten years even if all 32 ports are subscribed. The reality will be less than that given multiple competing infrastructure operators, so it might stretch to 15 or 20 years if growth in demand slows. That's another can of worms though...

If you look at the various statistics ISPs occasionally publish about peak demand on their networks, over 2020 the usual headline-generating numbers of terabits work out to just under 2Mbit per user at peak time, averaged over the whole customer base. Sky is an outlier at 3Mbit, or maybe I read the numbers wrong.

Granted these are mostly FTTC operators but it's quite interesting how when you get to averaging large numbers of users the speed matters less as the demand is for a number of bits to be moved, not for a fixed period of connection saturation. Consider a 60Gbyte game or OS update, this would saturate a theoretical 80Mbit connection for 100 minutes. It would take 8 minutes on a gigabit connection.

Chances are the 80Mbit ISP, given say 120 customers downloading a new game will have a fair number of them hammering that 80Mbit connection at the same time, because if they all buy the game when they get home from work between (say) 1830 and 2030 the first has barely finished downloading before the last starts. The reality is a more complicated distribution of course, but say those hundred customers buy the game evenly spread over those two hours, that's a download starting per minute. When the last one presses buy the first one is only just finishing their download, so you've got a peak of almost 120x80Mbit customers = 9.6Gbit.

The gigabit ISP with the same 120 customers in theory has a maximum demand of 120Gbit, but the reality is that the customers buy the game at different times. If they're evenly spread across the same two hours it's a download starting every minute, but everyone's download only takes 8 minutes to complete. With only 8 downloads going at the same time, the peak demand is more like 8Gbit.

So with this flat distribution of demand the gigabit ISP has lower upstream costs! As I said, the reality is not a flat distribution of demand but a curve that peaks around 9pm. I haven't the data or the mathematical ability to work out how that affects things, though.
Standard User jabuzzard
(experienced) Sun 02-May-21 22:07:22
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Re: The road to full fibre...


[re: DrPepper] [link to this post]
 
In reply to a post by DrPepper:
So, I am writing this connected to my local exchange by a bit of glass and light pulses. I cannot help wondering what the next step will be?


Shorter light pluses. Fibre optic is the end game for distance network communication. That fibre is good for at least 1Tbps if you change the optics at either end. Noting that single mode fibre put in 30 years ago to support 10Mbps Ethernet is good today with off the shelf components for 100Gbps Ethernet.

In some distant future there might be hollow fibre optical cable that will shave off a handful of nanoseconds of latency between you and your exchange. However unless you are a bottom feeding high frequency trader it's simply not worth it. Longer haul connections like over oceans and across continents and the like will probably get upgraded at some point because the difference becomes noticeable.
Standard User burble
(committed) Mon 03-May-21 13:09:35
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Re: The road to full fibre...


[re: DrPepper] [link to this post]
 
Well my first was a 56k sometime in the 90's, always getting moaned at for tying up the phone line.
Then it was 512k ADSL and a modem which plugged into back of pute.
Next it was 1.2Mb LLU with Tiscali as BT limited my line to 512k, I think this must have been when I first had a wireless router, but never fitted a wireless card so carried on with it plugged into back of pute.
Then came BDUK funded VDSL, we where promised 'superfast' was coming, I questioned the local council officer over this as we are so far from cabinet, and was assured we would get 'superfast', when it came to line estimates when ordering we where told 14MB, even this was wildly optimistic, and on average where getting 5MB.
Now we have BDUK funded FTTP, and for the first time have not had to optimise everything to try and get max speed, in fact we're on 110/20 which does all we want and 1GB there if we ever wanted it.


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Standard User Pheasant
(fountain of knowledge) Mon 03-May-21 14:12:23
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Re: The road to full fibre...


[re: jabuzzard] [link to this post]
 
In reply to a post by jabuzzard:
Noting that single mode fibre put in 30 years ago to support 10Mbps Ethernet is good today with off the shelf components for 100Gbps Ethernet.

In some distant future there might be hollow fibre optical cable that will shave off a handful of nanoseconds of latency between you and your exchange. However unless you are a bottom feeding high frequency trader it's simply not worth it. Longer haul connections like over oceans and across continents and the like will probably get upgraded at some point because the difference becomes noticeable.

You're probably a similar vintage to me. I was studying for my bachelors in EE and computer science in the early nineties (different hemisphere though).

The buzz around high-speed campus and MAN networking in the early nineties was all around 100meg FDDI and on the telco side of things it was ATM. The holy grail at the time was that 155M ATM would go all the way from the desktop to the telco core....it was certainly elegant and Ethernet, was errr not very!

Ethernet was the somewhat unexpected dark horse LAN-based upstart that came to eventually kill all its competitors and then some! Here we are today with 800G Ethernet in the works, and no signs of slowing...
Standard User kitcat
(experienced) Mon 03-May-21 17:19:09
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Re: The road to full fibre...


[re: DrPepper] [link to this post]
 
DrPepper

What you have done is move from Copper tech to Fibre tech, your question should be what comes after fibre tech. Answer is nobody knows but Sci-fi would theorise some sort of matter transmission or 'FTL' tunneling.

Likelyhood is fibre or radio will always be good enough for local comms ( Local being same planet!)

I started with punch tape and Teletex Machines with 110 baud to the GLC computers in London, Than various 300, 1200, 9.6kb 64kb, 128kb onwards to FTTC, ,all over copper. Still waiitng for Fibre at home but used it at work since the late 1980s. Never got beyond 80Gb in the real world but was aware of 160Gb + in the labs. by 2015.

With the potential for multiple frequencies over the same fibre the bandwidth limit is very high and I have no ideas of what usage would exceed what Fibre can handle given the correct end equipment. Whether anyone would want 80Gb at home for Domestic use with the power cost etc is the question. Business use has some potential but even then you are talking a medium size office not a single worker. ( Robotic office is more likely as the highest spec human cannot handle that data even as video!) .
Standard User JB68
(member) Mon 03-May-21 18:00:53
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Re: The road to full fibre...


[re: ft247] [link to this post]
 
Started with a 56k modem with 5kb/s, remember downloading a 700mb film which took 2 days to download!

Then got broadband with 1meg USB modem (blazing fast back then)

Then moved to ADSLMax which was about 5-6meg.

Then moved to ADSL2+ which gave me about 8-9meg speed.

Then moved to VDSL which gave me the 80 meg speed and now im on FTTP, 900 meg smile

My Broadband Speed Test
Standard User zyborg47
(legend) Tue 04-May-21 08:25:48
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Re: The road to full fibre...


[re: ft247] [link to this post]
 
Fibre is fibre is it not at the end of the day? Sure the electronics and other stuff makes a difference, but it is still light in a long glass thing smile sure the quality of the fibre would make a difference. The fibre used for FTTC and FTTH is better quality than that you used to connect your TV up to the sound bar or the stuff you may use for a 10Gb network.

What is next? I have no idea, but I doubt I will see it happen.


My problem with fibre is that it is very fragile,

Adrian

Desktop machine Ryzen powered with windows 10 , reluctantly.

Plusnet FTTC
Standard User Pheasant
(fountain of knowledge) Tue 04-May-21 09:56:31
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Re: The road to full fibre...


[re: zyborg47] [link to this post]
 
Most of the technical and engineering developments particularly in single-mode fibre of the last 30 odd years have been to engineer out the so called “water peak” - so called zero water peak fibre - which allows a much broader range of wavelengths or colours of light to be transmitted without losses at particular wavelengths and the refinement of fibre to be more insensitive to ever sharper bending radii - so called bend insensitive fibre.

9/125 micron single mode fibre still remains the “daddy” in terms of its combination of distance capability and information carrying capability. Multimode fibre is pretty much restricted to the enterprise market for longer runs of intra or inter building data links.

The plastic stuff used to connect your sound bar and TV (Toslink?) doesn’t really count as “proper” fibre in my view, let’s just say it’s a plastic waveguide!
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