Multipath TCP is an extension of TCP to allow end-to-end delivery over multiple simultaneous TCP paths. Multipath TCP was upstreamed for Linux 5.6 as a means of greater TCP performance/efficiency and redundancy . MPTCP has been around for years and the reference implementation for Linux remained out-of-tree but this year is finally all in mainline. In kernels since Linux 5.6 there has continued to be more tuning/additions around MPTCP .
Red Hat engineers are back-porting the Multipath TCP code to their RHEL8 kernel for distributing as a tech preview option beginning in RHEL 8.3.
Making use of MPTCP and the setup steps involved are outlined in this Red Hat Developer blog post .