Southern Cross Cable - How does it work?

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semigeek

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#97078 10-Feb-2012 09:35

A lot of people sit down and use their computers, laptops, tablets etc to access the internet, but probably don't give too much thought to how it works and I for one take the internet as granted.

So I thought it would be a good idea for the more geeky (no offence intended) of you to explain how the Internet works. Now I pretty much know how networks work, having worked in that field before, but I think more detail in how the Southern Cross Cable works to provide the internet to us, would be - lets say interesting.

For example:

1) What is the Southern Cross Cable connected to where it lands?

2) Is it weighted down or buried within the sea floor?

3) What happens if it gets damaged?

4) How fast can it send and receive information and how do they increase capacity on it?

5) What does it cost ISP's (ball park figure) to buy data?/Capacity on the cable?

This topic might be inane, but like I said, a lot of people probably don't give too much thought about where they get the internet from and how it works. So any information for those who don't understand would be good, me included. And learning is always a good thing right? :)

Sounddude

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#579863 10-Feb-2012 16:55

1) What is the Southern Cross Cable connected to where it lands?

2) Is it weighted down or buried within the sea floor?

3) What happens if it gets damaged?

4) How fast can it send and receive information and how do they increase capacity on it?

5) What does it cost ISP's (ball park figure) to buy data?/Capacity on the cable?

I have a fair amount of exposure to SCCN, but I don't know everything about it (so some of these answers may not be 100% true).

But here are my answers.

1) In NZ it lands at Takapuna beach and on the West coast. The Takapuna beach landing connects to the TKH landing station on Akaoranga Drive on the North shore. The West coast side connets to a landing station in Whenuapai. There is then a cable with connects the 2 landing stations together. This is part of the protection ring.

At the landing station is connects into a system which runs the amplifiers on the cable system. Bascially its a big DC power plant which sends DC signal down the cable which runs the optical amplifiers. From there the fibres then terminate into a big DWDM system and from that into a SDH Mux.

The DWDM system generates multiple wavelenghts (100gig each optical wavelength) and i belive they can send 64 wavelengths per fibre (can't remeber the exact number). They from memory only have 3 fibres on the cable.

The SDH mux is use to sell of smaller chunks of bandwidth (STM1, STM4, STM16, STM64) bandwidth lots.

There is some good diagrams on this website.

http://www.southerncrosscables.com/public/Backhaul/default.cfm

2) its weighted down, not buried. But the cable itself is armoured. This is why boaties are not allowed to anchor in parts of the harbour, incase it gets ripped up.

3) Alcatel-lucent look after the cable, and they have ship which covers the APAC Region. This ship in the event of a break will go to the break location, and using subs find the cable and haul both ends up onto the ship. They then splice the cable back together, fix the amour and drop it to the floor again.

meanwhile, the ring formation of the cable system provides the carriers protection. The latency will be a tad higher, but service will continue. (Assuming the carrier has bought a protected service)

4) They increase the bandwidth buy increasing the amount of wavelenghts in their DWDM system. Optical equipment is improving all the time.

Hope I have helped!

mxpress

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#579872 10-Feb-2012 17:24

Awesome answer. Thank you.

mxpress

Beccara

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#579874 10-Feb-2012 17:28

Just a couple of corrections here:

SCC runs on 16 wavelengths, each are at 40gbit which is an upgrade just done, 100gbit wavelengths will be deployed by the end of 2012, they also run 3 pairs on the network.

Only sections of the cable are armored, For example the section for AKL to Hawaii is about 8,000 km long but below 500km of that is armored

The cost to ISP for a circuit is quite a bit and depends on the type of connection the ISP buys, A protected circuit from AKL to LA at STM-16 will set you back upwards of $5mill NZ, 10gbit is north of 15mill. A 3 drop circuit which is 3 seperate circuits of AKL-SYD, SYD-LA,LA-AKL each at STM-16 will set you back upwards of $30mill NZ over 13 years.

SCC is just one part of the system tho, The tail circuits from the landing stations in NZ to somewhere you can use it in auckland can be quite higher and close to the monthly cost of the SCC circuit.

Atleast when you hit LA you can buy global transit for under $2/mbit

Most problems are the result of previous solutions...

All comment's I make are my own personal opinion and do not in any way, shape or form reflect the views of current or former employers unless specifically stated

Ragnor

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#579878 10-Feb-2012 17:36

To further answer #5

Most ISP's buy international transit from resellers not directly from SXC because:

1) Resellers offer an end to end service with interconnection/peering at each end (AU, NZ, US) into other networks/the internet.

2) Many NZ ISP's are not large enough to buy in the capacities that SXC sells directly.

NBR has a good article covering some aspects of SXC
http://www.nbr.co.nz/opinion/chris-keall/meet-bad-guy

ISP's also buy bandwidth (in Gbit/s or Mbit/s) not "data" used.

It's not economically viable to buy 10Mbit for every ADSL user with a 10Mbit line rate, ISP's buy x Mbit/s for y customers, that ratio between users and bandwidth is called the contention ratio. Better ISP's have lower contention, Cheaper ISP's have higher contention.

Data caps just happen to be a cheap way to ration usage and make sure users do decide to download 24x7 which would increase congestion on the available bandwidth.

The main resellers are: Global Gateway (Telecom), Reach (Telsra), Vocus, Odyssey (Kordia/Orcon), Verizon and Pacnet.

ISP's may have capacity from multiple resellers for redundancy and load balancing or not. It's quite easy to guesstimate what international transit an ISP is using by doing tracerts.

The price of transit is commercially sensitive and depends on negotiations and contracts ie: it varies on the size transit the ISP purchasing and the length of the contract etc.

DonGould

3892 posts

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#579923 10-Feb-2012 19:29

http://www.pipenetworks.com/ppc1blog

Thanks to Bevan for finding the link for me... You really want to know about undersea cables then have a read about PPC1. The blog is fantastic and anyone who is any sort of geek should read this from cover to cover to learn some very cool stuff!

D

Promote New Zealand - Get yourself a .kiwi.nz domain name!!!

Check out mine - i.am.a.can.do.kiwi.nz - don@i.am.a.can.do.kiwi.nz

knoydart

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#579941 10-Feb-2012 20:06

And for a bit of history of sub sea cables with some extra geek value thrown in, this article from Wired from a good few years ago but is excellent
reading none is less

webwat

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#579954 10-Feb-2012 20:44

I think there is some armouring all the way underwater, but sections at depths where it attracts sharks, anchors or fishing traulers have the extra steel armour that makes it so bulky. The cable is buried where it comes into the landing point, maybe out to water depth of 20m or more. It also contains power cable for the EDFA amplifiers and waterproofing layers. Telecom had a cutoff of the armoured cable on display at a boat show once, over 10cm thick just to protect some microscopic strands of fibre in the middle. Sydney also has a patrol boat dedicated to educating fishos about the dangers of snagging a cable.

The new Pacific Fibre and Kornet cables are supposed to be native Ethernet instead of SDH, so would be interesting to know what gear they plan to use instead of a SDH mux (which does TDM multiplexing for each wavelength). Each laser transmission might be tuned to minimise non-linear effects and put through a wavelength multiplexor before it gets amplified. Received wavelengths on the other fibre get split into individual signals in the same way.

Time to find a new industry!

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semigeek

1606 posts

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#579984 10-Feb-2012 21:50

Sounddude:

1) What is the Southern Cross Cable connected to where it lands?

2) Is it weighted down or buried within the sea floor?

3) What happens if it gets damaged?

4) How fast can it send and receive information and how do they increase capacity on it?

5) What does it cost ISP's (ball park figure) to buy data?/Capacity on the cable?

I have a fair amount of exposure to SCCN, but I don't know everything about it (so some of these answers may not be 100% true).

But here are my answers.

1) In NZ it lands at Takapuna beach and on the West coast. The Takapuna beach landing connects to the TKH landing station on Akaoranga Drive on the North shore. The West coast side connets to a landing station in Whenuapai. There is then a cable with connects the 2 landing stations together. This is part of the protection ring.

At the landing station is connects into a system which runs the amplifiers on the cable system. Bascially its a big DC power plant which sends DC signal down the cable which runs the optical amplifiers. From there the fibres then terminate into a big DWDM system and from that into a SDH Mux.

The DWDM system generates multiple wavelenghts (100gig each optical wavelength) and i belive they can send 64 wavelengths per fibre (can't remeber the exact number). They from memory only have 3 fibres on the cable.

The SDH mux is use to sell of smaller chunks of bandwidth (STM1, STM4, STM16, STM64) bandwidth lots.

There is some good diagrams on this website.

http://www.southerncrosscables.com/public/Backhaul/default.cfm

2) its weighted down, not buried. But the cable itself is armoured. This is why boaties are not allowed to anchor in parts of the harbour, incase it gets ripped up.

3) Alcatel-lucent look after the cable, and they have ship which covers the APAC Region. This ship in the event of a break will go to the break location, and using subs find the cable and haul both ends up onto the ship. They then splice the cable back together, fix the amour and drop it to the floor again.

meanwhile, the ring formation of the cable system provides the carriers protection. The latency will be a tad higher, but service will continue. (Assuming the carrier has bought a protected service)

4) They increase the bandwidth buy increasing the amount of wavelenghts in their DWDM system. Optical equipment is improving all the time.

Hope I have helped!

Great info, thanks. I for one have learnt something. As I am sure others have.