On English canals, is a licence really necessary?

[cuthound]

10 hours ago, MartynG said:

Its called the web or the net for a reason. Unlike a single pipeline you can  blow a hole in it and apart from local issues  there are still other routes 

But if the internet was seriously disrupted or destroyed then yes it would be catastrophic .

 

Indeed and data centres, where the data is stored are duplicated and for really important data triplicated or more. These operate as "hot standbys", so are already up and running and can be switched almost instantaneously. All of this is addition to the duplicated standby power and cooling systems within each data centre.

 

Most of the issues with the internet are of the human error type, particularly when updating software.

Edited October 6, 2022 by cuthound
To unmangle the effects of autocorrect.

[Momac]

Therefore the OP should not rely on the destruction of the internet when considering whether to license the boat he is yet to purchase.

 

 

[alias]

1 hour ago, cuthound said:

Indeed and data centres, where the data is stored are duplicated and for really important data triplicated or more.

 

They can be, but not all organisations are willing or financially able to pay the additional costs of doing so. DAMHIK

[cuthound]

8 minutes ago, alias said:

 

They can be, but not all organisations are willing or financially able to pay the additional costs of doing so. DAMHIK

 

Every data centre I fitted out had a duplicate one, but as you say some minor organisations (not many in my experience and certainly no major players) do not take advantage of the hot standby data centre.

[IanD]

8 hours ago, jonathanA said:

Exactly my point submarine systems of 320TB/s are commercially available now. 

Starlink is about using standard mobile phone handsets with LEO satellites so bandwidth will be in 10's or 100's Mb I would guess (to a handset)

Starlink currently is about using dishes (a flat phased array antenna really...) to provide wireless internal access for homes (and ships and vehicles which can fit one in) -- each one is typically 50-100Mbps down and 5-10Mbps up.

 

Reaching mobile handsets is *way* more difficult because the antenna gain is so much lower and so is handset transmit power, which means data rates will also be way lower -- maybe enough to support text/voice/low-rate video at best, nowhere near current Internet access speeds.

 

Even to do this will need the "Gen 2" Starlink satellites which are 5x the size and weight of Gen 1, and will need Starship to launch them.

 

The plan is to be able to provide such essential (e.g. emergency) mobile access everywhere, not for people to watch cat videos in the middle of nowhere... 😉

Edited October 6, 2022 by IanD

[Ray T]

In my working career I had to know all about light wave propagation.

 

All you need to know. 😆

 

Light Propagation in Optical Fibers Study Notes (byjusexamprep.com)

 

Optical Fiber Communication : Structures, Waveguiding, and Fabrication (theteche.com)

 

 

Edited October 7, 2022 by Ray T

[mrsmelly]

15 hours ago, MartynG said:

Therefore the OP should not rely on the destruction of the internet when considering whether to license the boat he is yet to purchase.

 

 

I think this particular sock puppet is long gone.

[David Mack]

55 minutes ago, mrsmelly said:

I think this particular sock puppet is long gone.

Yup. Joined on 27 Sept when he started this thread, and last visited on 28th.

[1st ade]

23 hours ago, IanD said:

each of which typically carries about 10Tb/s of traffic,

 

Er no; each of which carries (typically) 80 different colours of light each of which carries around 10 Tb/s - it's not uncommon now to have ~800Tb on a fibre and across the Atlantic a "cable" may have four fibre pairs

20 hours ago, Ronaldo47 said:

Just dug out a prepared sample of a multi-strand fibre optic cable that a colleague who used to deal with that technology, gave me in the late 1990's

I'd tentatively say that example was relatively "short haul" - for over ~200km the costs of the repeaters (or amplifiers or optical regeneration - take your pick) tends to dominate - so providers go for two or four pairs and really reliable - for short haul across the north sea where you don't need amplifiers, the biggest i've heard of is 196 pair

[IanD]

21 minutes ago, 1st ade said:

 

Er no; each of which carries (typically) 80 different colours of light each of which carries around 10 Tb/s - it's not uncommon now to have ~800Tb on a fibre and across the Atlantic a "cable" may have four fibre pairs

I'd tentatively say that example was relatively "short haul" - for over ~200km the costs of the repeaters (or amplifiers or optical regeneration - take your pick) tends to dominate - so providers go for two or four pairs and really reliable - for short haul across the north sea where you don't need amplifiers, the biggest i've heard of is 196 pair

For long-haul traffic a typical optical carrier nowadays occupies 75GHz of bandwidth and carries 200Gbps of data. The lowest-loss C-band is 4.4THz wide and can carry 58 of these channels (different colours of light), which is 11.8Tbps. Older less efficient systems have 88 50GHz channels carrying 100Gbps each, which is 8.8Tbps. Shorter-reach metro systems use more complex modulation (400Gbps in 75GHz) which doubles the capacity per fiber to 23.6Tbps -- all numbers per fiber, cables have multiple fibers.

 

And yes I'm sure about these numbers, I was (and still am) responsible for the design of most of the coherent transceiver chips that do this -- 85% of the worldwide market a few years ago, rather less nowadays with more competition in the market... 😉

Edited October 7, 2022 by IanD

[Maffi]

On 28/09/2022 at 11:20, NN247 said:

My practical purpose is that I'm considering buying a boat that needs an interior makeover, and I'm costing that out to see if the level of profit would be worth it.  I'd need to move it from where I buy it to where I'd work on it, so I'm just trying to see if I really need to spend hundreds of pounds just for a couple of weeks only to put in drydock where the license would be wasted, or if I could feasibly skip that, and only buy a license at the end of the renovation/let the next owner buy the license.

If you just want to move it to a dock talk to CRT. They have an explorer licence that's valid for a month.

 

PS why didnt you just say what you wanted to do?

Edited October 7, 2022 by Maffi

[enigmatic]

On 07/10/2022 at 11:34, David Mack said:

Yup. Joined on 27 Sept when he started this thread, and last visited on 28th.

Which was the fateful day his boat was torpedoed by the boat licence police...

[Momac]

On 07/10/2022 at 14:05, Maffi said:

If you just want to move it to a dock talk to CRT. They have an explorer licence that's valid for a month.

The explorer license is valid for 30 days ,but not necessarily 30 consecutive days. It's valid for a year. 

The explorer license and other short term licenses are   aimed at boat visiting from outside C&RT waters and not located  in marians connected to C&RT waters.

I am sure some boat owners already fraudulently claim their boat  to be based outside C&RT waters in order to obtain the explorer and other short term licenses.

[Chris101]

Was reading this thread yesterday and saw the linked animation of submarine networks today so thought I'd share. It's a link to Imgur and perfectly safe. It's too large to be hosted on here at least with my limited technical knowledge.

https://imgur.com/gallery/o2CAvTVhttps://i.imgur.com/TSTGuwe.mp4https://i.imgur.com/TSTGuwe.mp4

 

 

[alias]

13 minutes ago, Chris101 said:

Was reading this thread yesterday and saw the linked animation of submarine networks today so thought I'd share. It's a link to Imgur and perfectly safe. It's too large to be hosted on here at least with my limited technical knowledge.

https://i.imgur.com/TSTGuwe.mp4

 

 

Link fixed

[PD1964]

9 hours ago, Chris101 said:

Was reading this thread yesterday and saw the linked animation of submarine networks today so thought I'd share. It's a link to Imgur and perfectly safe. It's too large to be hosted on here at least with my limited technical knowledge.

https://imgur.com/gallery/o2CAvTVhttps://i.imgur.com/TSTGuwe.mp4https://i.imgur.com/TSTGuwe.mp4

 

 

In reality to the original OP’s thread, absolutely nothing to do with it, but nice to watch though.

[LadyG]

On 06/10/2022 at 12:59, IanD said:

One submarine optical cable has multiple fibers in it, each of which typically carries about 10Tb/s of traffic, and there are far more links within countries/continents. One link to a Starlink satellite carries far less than this (by orders of magnitude e.g. 100Gb/s), so even with the projected 40000+ satellites their total capacity will be a tiny fraction of the optical fiber network.

 

It's all down to bandwidth; the millimeter-wave satellite links have bandwidths measured in GHz, for optical fibers this is in THz...

I think the Isle of Wight recently lost BT due to random fishing for cables so some things are easily disrupted.