Largest cruise liner gets outfitted with fiber like Internet | Hacker News Reader

Largest cruise liner gets outfitted with fiber like Internet

o3bnetworks.com

4 pointsrpoo6 comments

Well damn. I misread the headline and already started thinking through how aggressive you would have to cache if you were on a cruise liner, had a satellite connection to the rest of the world, but had fiber across the ship for guests.

Then I read how O3 does it - apparently the satellites track the ship and you get a dedicated link. Good god that has to be expensive.

Definitely expensive..but compared to what exists now, probably worth it. How else will people be able to upload vacation photos to instagram!

"which delivers the reach of satellite and the SPEED and LATENCY of FIBER"

False marketing of the month!

Well, technically - if you're thousands of miles out to sea, bouncing a signal to a satellite in orbit a few hundred kilometers above the earth may well equal the speed and latency of an equivalent fiber connection...

GEO is 22236 miles up. Consider that you'll usually be bouncing data at least 50000 miles through the lossy atmosphere. It's the distance and lost packets that cause the main latency issues.

You could got for a LEO (upward of 500m) but they need much more power to stay up and you need so many more satellites. It's not impossible but I would have thought it to be prohibitively expensive for an ISP (or a cruise liner full of oldies).

Not to mention that this thing is going to connect to a base station and you're then your connection is in the hands of the actual fibre gods.

Compare that to a real connection: I have ADSL in the UK. I ping a server of mine in California. ~5000miles in 130ms. You could spend billions on a peering satellite network and your first hop (past any boat-board proxy) will still be longer than a DSL equivalent's whole TCP connection.

Unless, that is, they're using unicorns to beam the data with fairy dust neutrinos. That probably would be faster.

Note: I'm not saying annything about bandwidth. You can get crazy-high bandwidth through a P2P dish, but latency has always been an issue when you're dealing with orbits and the atmosphere.

Communications satellites typically use a geostationairy orbit. The advantage of this is two-fold:

1) Your antenna need not "track" the satellite to hold a signal

2) There is no gap in connectivity required to track to another satellite when one goes out of range/view

A geostationary orbit, as Oli pointed out, is way up there. At that distance, there are some physics that limit the minimum latency.

RTT between the satellite to the ground is around 250 ms, but that's only for one leg. RTT for any other endpoint on earth is going to have a minimum travel time of 500 ms. Return communications must use the same link, which adds in another 500 ms of latency. All of this adds up to a minimum of around 1 second latency on a good day. The physics of the matter dictate that satellite can never match fiber at the physical layer.

I have a feeling that they're using some sort of caching strategy to meet that fiber latency claim. That works fine for people who want to browse the news or catch up on a blog, but for things like webmail and Facebook, it's going to be painfully slow.

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