The X-Bone dynamically deploys and manages Internet overlays to reduce
configuration effort and increase network component sharing. The
X-Bone discovers, configures, and monitors network resources to create
overlays over existing IP networks. Overlays are useful for deploying
overlapping virtual networks on shared infrastructure and for
simplifying topology.

The X-Bone's two-layer IP in IP tunneled overlays support existing
applications and unmodified routing, multicast, and DNS services in
unmodified host operating systems. This two-layer scheme uniquely
supports node revisitation and recursive overlays, which is critical
for fault tolerance and dynamic relocation. The X-Bone uses multicast
to simplify resource discovery, and provides secure deployment as well
as secure overlays (VPNs).

WWW:	http://www.isi.edu/xbone/