In one embodiment, a method comprises selecting, by an ingress provider edge router, one of first or second provider edge routers as a primary router for reaching a destination via a core network, and selecting the other of the first or second provider edge routers as a backup router for reaching the destination via the core network; and inserting, into an IPv6 data packet destined for the destination, a primary label assigned by the primary router and a repair label assigned by backup router, and an IPv6 extension header specifying first and second segment identifiers associated with the respective first and second provider edge routers and a protected flag that enables fast rerouting of the IPv6 data packet to the backup router if the primary router is unavailable.