there's a lot of interesting problems just in the networking.

if it took four years for a message to cross the void from where you are to the recipient, you certainly wouldn't want to wait a full eight years to see they didn't send a receipt message and only then retransmit.

eight years is some awful latency.

you'd probably want to send each message at something like a fibonacci over the months. so, gaps of (1, 1, 2, 3, 5, 8, etc) would mean sending the message on months (1, 2, 4, 7, 12, 20, 33, etc) until you got a confirmation message that they had received it. they would similarly want to send confirmations in the same sort of pattern until they stopped receiving copies of that message.

spreading the resends out over time would ensure not all of your bandwidth was going to retransmissions. you'd want that higher number of initial transmissions in hopes that enough of the message makes it across the void that they would have started sending receipts reasonably close to the four years the initial message would take to get there.

if you had the equivalent of a galactic fido-net system, it could be decades and lifetimes between messages sent to distant stars and messages sent back.

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furyofantares 2 days ago | parent | next [-]

Wouldn't you want to completely saturate your bandwidth? Just always be transmitting whatever message has been transmitted the least.

	▲	knome 2 days ago \| parent [-]
		that would probably depend on how much power it takes to send the messages, how much actual usable bandwidth you could manage over the distances involved, and how much data you want to send. if it takes a large amount of energy to send the data, we probably wouldn't want to run the equipment all the time. strong pulses would let the equipment cool down or recharge capacitor banks or whatever during downtime. interstellar dust and other debris floating through space could cause interference, not to mention radiation from everything else around us, and our own sun shining right next to our little laser. might want to move the laser out onto pluto or something to avoid having it right up against the sun.

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toast0 2 days ago | parent | prev | next [-]

You'd want to do a lot of work with erasure codes as well.

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Sanzig 2 days ago | parent | prev | next [-]

It would be a lot more efficient to use erasure coding + heavy interleaving with other traffic so that you can withstand a maximum predicted outage period.

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scottyah 2 days ago | parent | prev [-]

and you'd probably want to take orbits/vectors into account, a djikstra-esque algorithm where the distances change is crazy.

Also, our signals are usually going very short distances very quickly and are very protected from solar/cosmic waves by the ionosphere. What kind of data loss could you get transmitting in open space across vast distances and time?

	▲	Sanzig 2 days ago \| parent [-]
		Interstellar space is pretty empty, and we have good models for it thanks to the radio astronomy community. Dispersion is low enough to be nearly negligible, even over tens of light years. Determining theoretical interstellar link rates is a fairly straightforward link budgeting exercise, easier in fact than most terrestrial link calculations because you don't have multipath to worry about.