Links between internet exchanges and cable landing stations

I was thinking the other day that I've never really heard any mention of how the internet exchanges are connected through to the cable landing stations, does anybody in the know have any info on this?

Maybe take Cornwall as an example where there are numerous cable landing stations, which cables running all over the world. I've read these are connected on a ring.

So how would traffic from LINX find its way from London to one of these submarine cables?

A fibre optic backbone/trunk route

So would that be via a little data centre at the cable station? So various internet exchanges can connect into the marine cables? They must have some powerful routers...

I just thought it a little odd as it�s all somewhat hidden away in Cornwall

I expect Cornwall was originally chosen as the geographically closest point on the mainland to start running telegraph cables to the States under the Atlantic , saved a couple of quid on cables no doubt.

And thus it has just evolved there.

The original US/UK landing station was Oban.

Some of the Trans-Atlantic Cables head out from the west coast of Scotland.

As well as slightly reducing the lengths as Zarjaz has said, because of the nature of the coastlines and depth of sea-bed in those parts, gives some protection from shipping, anchors and fishing trawls.

If a cable gets damaged or broken, it is very costly for a highly--specialised cable ship to head to the general area of the break, locate it specifically, , dredge up the broken ends, cut back to a good section, not damaged by water ingress, splice the replacement cable in at one end, then move possibly a mile or a kilometre to the suitable point in the other part; going through the whole rigmarole at the other end.

In itself, depending on the sea depth; and the angles of dangles, there may be similar lengths of cable unsupported during the operations, thus liable to further damage.

The end result of that part is that the repaired cable is now longer than the original, straight-laid cable.

The structure and impedance of the replacement cable must be reasonable matches to the original cable, to avoid reflections and losses, as Zarjaz is aware of by his use of TDRs/JDSUs.

Such cable may not be available "off-the shelf" etc.

Once the initial physical repair has been carried out, the repaired cable has to be tested, end-to-end, to ensure that the necessary electrical parameters are met.

All on the stormy ocean and sea, with tidal surges etc.

https://en.wikipedia.org/wiki/Cable_layer

http://www.kis-orca.eu/subsea-cables/maintenance-rep...

Note the sizes of those ships.

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Oil and gas under-sea pipelines have similar arrangements, along with the few Electricity Inter-Connetors.

Edited by deleted (Fri 05-Jan-18 19:21:43)

I get how the marine cables work. My question was more the separation of the cable landing stations and the internet exchanges.

You have the London internet exchange using terabytes of bandwidth, and the marine cables with terabytes of bandwidth... but a huge distance between London and Cornwall

Was trying to picture what links the two together.

Yeah, but the Yanks couldn�t understand the accents on the telegrams.

Fibre, fibre and more fibre.

The routers are typically in the major datacentres in places like London and Manchester. Providers such as ourselves (Zen), and others, will then lease, or have their own connectivity (either wavelengths from bigger providers, or dark fibre which the providers then light themselves) to the cable landing stations in Cornwall/Southport/East Anglia and so on. This is the fibre, fibre and more fibre that Zarjaz speaks of.

Hope this helps,

Jon

Edit to add:

In reply to a post by Ripley:

I just thought it a little odd as it�s all somewhat hidden away in Cornwall

You'd be surprised where a lot of it is hidden away. On a related note, which Zarjaz can probably relate to - you get an eye for places such as this, especially BT exchanges. Now I can spot the OBASS card reader a mile off!

Edited by deleted (Fri 05-Jan-18 20:41:30)