Connecting MPLS-SPRING Islands over IP Networks
MPLS-SPRING is a source routing paradigm in which a sender of a packet is allowed to partially or completely specify the route the packet takes through the network by using stacked MPLS labels. The current MPLS-SRPING architecture requires an end-to-end MPLS Label Switched Path (LSP) between any two MPLS-SPRING-enabled routers (e.g., two adjacent hops of a given explicit path). In order to enable MPLS-SPRING-enabled routers to be deployed even when there are non-MPLS routers along the path between two MPLS-SPRING-enabled routers, it is desirable to have an alternative, which allows the use of IP-based tunnels (e.g., GRE tunnels) to connect two MPLS-SPRING- enabled routers. This document describes a mechanism for such usage.