[HECnet] Bridge vs tunnel

I?ve been running the bridge program for quite some time now and every time the tunnel topic pops up I ask myself whether it would be better to move over as well. I have a fixed public IP address, and have hecnet area 44 all for myself. The bridge program and A44RTR (simh VAXserver 3900 VAX/VMS 6.1) run on an old laptop under fedora v 21. What do I need, in terms of software, hardware, to move to a tunnel? My Cisco knowledge dates back to the Cisco MGS router (IOS 7) :-) Hans