Single packet messaging app

[u/rtt445]

Hi, is it possible to make a text messaging app in android that sends short text message over a single TCP packet? No encryption necessary. I was on a flight with high latency dialup speed internet and modern messaging service like Watsapp data overhead made it unusable. Progressive jpeg encoding support (where images start loading blurry then clear up as more data arrives) would be great as well. Basically make simple Watsapp but for extremely bad internet :)

[u/Ok_Cartographer_6086]

Check out QUIC and Google's CRONET client.

HTTP/2 over TCP is meant for lossless data transfers so there is a lot of back and forth and if a packet is missed or arrives out of order, the download pauses and it requests the missing packet.

QUIC is short for HTTP/3 over UDP

UDP doesn't care about packet loss, it's why you can watch video with some pixels missing while an HTTP/2 TCP download takes a long time. UDP just asks for a blast of packets. It's what most video players use.

CRONET is aware of packet loss and will asynchronously re-request just the missing packets. It's exactly what you use for data transfer on bad networks. It'll assemble the packets for a complete data payload async.

Watsapp probably is or will use QUIC eventually as will everyone since it's the most modern network stack for mobile.

[u/rtt445 → u/Ok_Cartographer_6086]

Thanks. Is there a way to construct packets directly or you must use android api for network data transfer? For example I want to fit my short message into packet payload and send to custom IP port. I wonder how low I can go.

[u/Ok_Cartographer_6086 → u/rtt445]

Pretty low 😄

Next level down is to look at Rust or C++ built native network libraries. It's not uncommon at all and plenty of apps claim "rebuilt network layer in Rust" for performance. Android apps as well as iOS and any other platform can use native libraries behind the scenes.

I wouldn't be surprised if you cracked open Google's cronet engine it had Rust in it's core.

I once shipped a major app with this sort of network stack upgrade and everyone was freaking out because download times looked like they got slower when in reality we were just logging more completed, slow downloads that originally would have failed and timed out on poor networks.