2. Overview

This document defines a method of connection establishment, named the "Happy Eyeballs Connection Setup". This approach has several distinct phases:

1. Initiation of asynchronous DNS queries (Section 3)

2. Sorting of resolved destination addresses (Section 4)

3. Initiation of asynchronous connection attempts (Section 5)

4. Establishment of one connection, which cancels all other attempts (Section 5)

Note that this document assumes that the preference policy for the host destination address favors IPv6 over IPv4. IPv6 has many desirable properties designed to be improvements over IPv4 [RFC8200]. If the host is configured to have a different preference, the recommendations in this document can be easily adapted.