Perhaps it's time to revisit UDPIP. Does Linux
support the use
of UDP port 94 for encapsulation?
It appears it has been introduced in kernel 3.18 which is quite recent and
will mean there are some issues for many users.
(requirement to install a backported kernel and "ip" program that supports
the newly introduced "ip fou" subcommand.
It is not supported on the systems we are currently running.
(Debian Wheezy and Jessie)
It also is not supported on MikroTik routers.
Rob