The plan is to add more backends; we started with userspace encapsulation because it works everywhere and is easy to setup and control.
Initially we wanted to use an existing in-Kernel encapsulation format like a simple ip-ip encapsulation. However, IP-IP doesn't work on AWS. Then we looked at VXLAN but it relies on multicast which doesn't work on most cloud networks either. Most recently we started looking at the VXLAN DOVE extensions and are getting a prototype together for this.
tl;dr the initial goal is to show that something generic is needed and can work, we will get something that is performant and/or has encryption next.
Initially we wanted to use an existing in-Kernel encapsulation format like a simple ip-ip encapsulation. However, IP-IP doesn't work on AWS. Then we looked at VXLAN but it relies on multicast which doesn't work on most cloud networks either. Most recently we started looking at the VXLAN DOVE extensions and are getting a prototype together for this.
tl;dr the initial goal is to show that something generic is needed and can work, we will get something that is performant and/or has encryption next.