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Comment by saurik | Hacker News Reader

A big problem with TCP's loss avoidance is that it assumes the cause of loss is congestion, so if you use it on a network with random packet loss it can just get slower and slower and slower until it effectively stops working entirely.

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Agreed that it's a problem but probably not a huge one today on the internet since most loss is actually a result of congestion.

It has led to some weird things whereby the L2 protocols (thinking wifi and LTE/cellular) have their own reliability layer to combat the problem you're describing. I'm not sure if things would be better or worse if they didn't do this and TCP was responsible, the iteration of solutions for it would be much slower and probably could never be as good as the current situation where the network presents a less-lossy layer to TCP.

We have to completely rethink things for interplanetary networking.

I thought I recognized your username, I remember jailbreaking the original iPhone on IRC with you helping :)

> I thought I recognized your username, I remember jailbreaking the original iPhone on IRC with you helping :)

Yep, same author of Cydia [1].

[1] https://en.wikipedia.org/wiki/Cydia

Sure, but this is a simulator with random packet loss that has nothing to do with congestion, isn't it?

That's what TCP-SACK (Westwood variant) and SCPS-TP are for, to deal with packet loss due to bit corruption as well as congestion.

https://egbert.net/images/tcp-evolution.png

https://en.m.wikipedia.org/wiki/Space_Communications_Protoco....

Similarly, I wonder if nyxpsi has congestion control? It's probably tricky to implement if you are trying work with a crap network. I guess you could see how packet loss or latency responds to throughput, but then you need to change the throughput periodically while transmitting, which slows down the transfer.

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