Xen Argo and uXen v4v are both descendants of Citrix Xenclient v4v.
For future system architectures based on HAT (Hardened Access Terminal), which may include an L0 nesting-optimized hypervisor (Bromium AX, OSS PX - Protection Hypervisor) and L1 guest-optimized hypervisor (Xen, KVM, uXen, Hyper-V, ESX), we will need a single inter-domain communication mechanism that is compatible with multiple hypervisors.
As an intermediate step, create a version of Argo that is compatible with Xen and uXen. Identify differences (e.g. nameservice, fixed domain ID<->roles, firewall, connection tracking) between the implementations. This is a necessary stepping stone to interoperability with Bromium's commercial offerings.