IPv6 traffic may be carried through an MPLS IPv4 network without the use of IPv6-over-IPv4 tunneling. An IPv6 packet is sent through the MPLS IPv4 network through a label switched path (LSP). The IPv6 packet is encapsulated with a label stack associated with the LSP. A second level label is used in the label stack (in addition to the label associated with the LSP). This second level label provides important benefits.