This presumes humanity is a space fairing or interplanetary civilization.
How would something like the fediverse, internet, cryptocurrency, etc function with major latency? As an example, a signal takes between 5 and 20 minutes to travel from earth to mars. A roundtrip response would take at best 10 minutes and at worst 40 minutes. Now lets say you live on mars and your home lemmy instance is mars.social. You want to see what news people are chatting about on earth and heard that !news@beehaw.org is a good community. If you put that into your instance search box on mars.social the absolute best you can hope for is a response in 10 minutes. I assume the request would totally fail anyway due to rtt being set to low and the packets expiring before they ever reached the destination. The internet we all know and love is totally intolerant of high latency. Just ask people who use satellite internet or tor.
Edit: i think, but am not certain, that ipv6 replaced rtt with hop count. If so this may not be an issue as the time it takes would not matter as long as the hop limit was not reached.
For internet between Mars and Earth you have to deal with a peak latency of twenty minutes, forty for duplex. I don’t think TCP/IP is designed in any way to deal with that. You’d have to come up with a translational protocol with TCP/IP buffers on either end. I don’t think it would be that difficult to engineer in terms of current technology.
Another issue is link speed and bandwidth, the distance causes signal degradation. You have to run transmission speeds lower. It might be possible to use repeater satellites to alleviate issues. That’s commonly done on Earth bound communications.
There is a way to create data links that don’t rely on RF using quantum entanglement. It would be zero latency across all of space. It’s sci-fi tech, but it’s hugely more feasible than things like warp drives and transporters. We’re already developing tech that utilizes quantum states .