A method for operating a router has the following steps. First, the router
receives a data packet to be forwarded, the data packet having an
indication that it is to be routed by tag switching to a destination
router, the destination router to forward the packet to a destination
computer. Second, the router prepends a tag to the data packet, the tag
to be used by the destination router to route the data packet to the
destination computer. Third, the router prepends an encapsulation header
to the data packet, the encapsulation header to route the data packet to
the destination router. Fourth, the router transmits the data packet with
the encapsulation header and the tag for routing through the network to
the destination router.