Delay-based netcode
Also said as Input delay netcode, Frame delay
Hold your own inputs back for a few frames, so that the other machine's inputs for the same frame have time to arrive. If they still have not, freeze until they do.
Nothing on screen is ever wrong and the idea is simple. The cost is that the controls change with the connection: play someone far away and your character answers late, and any spike stops the game dead.
Say it
“If we must ship delay-based, fix input delay at 4 frames across all connections so that the feel is steady, and only add more above 130 ms of ping.”
Where you’ve seen it
Guilty Gear Strive's closed beta still ran on Arc System Works' earlier delay-based connection. Rollback got its first public test in the open beta in 2021, and fighting game pros praised it.
Not to be confused with rollback
Both are ways of waiting for the other player. Delay-based waits before it shows you anything. Rollback shows you straight away, and fixes it later if it has to.