[vitus]

> magic eyeballs

https://en.wikipedia.org/wiki/Happy_Eyeballs is the usual name. It's not quite identical, since you often want to give your preferred transport a nominal headstart so it usually succeeds. But yes, there are some similarities -- you race during connection setup so that you don't have to wait for a connection timeout (on the order of seconds) if the preferred mechanism doesn't work for some reason.

The main term I've seen for this particular approach is "request hedging" (https://grpc.io/docs/guides/request-hedging/, which links to the paper by Dean and Barroso).

[spockz]

Request hedging or backup requests are indeed the terms I know for requests where you give the first request a bit of a headstart. I didn’t know about the term happy eyeball to signify that all requests fire at the same time.

[vitus]

> I didn’t know about the term happy eyeball to signify that all requests fire at the same time.

It's not quite the same. Usually with Happy Eyeballs, you want to try multiple protocols (e.g. QUIC vs TCP, or IPv6 vs IPv4), and you have a preference for one over the other. As such, you try to establish your connection via IPv6, wait something like 30ms, then try to establish via IPv4. Whichever mechanism completes channel setup first wins, and you can cancel the other one.

It's a mechanism used to drive adoption of newer protocols while limiting the impact on end users.

[100ms]

Happy eyeballs, that makes a lot more sense thanks. Someone's "magic eyeballs" here apparently isn't reading his own writing :)