IPv6 SR-TE LSP Support in MPLS

This feature is supported with the hop-to-label, the local CSPF, and the PCE (PCC-initiated an PCE-initiated) path computation methods.

All capabilities of a IPv4 provisioned SR-TE LSP are supported with a IPv6 SR-TE LSP unless indicated otherwise. There are, however, some important differences with an IPv4 SR-TE LSP which are explained below.

The IPv6 address used in the from and to commands in the IPv6 SR-TE LSP, as well as the address used in the hop command of the path used with the IPv6 SR-TE LSP must correspond to the preferred primary global unicast IPv6 address of a network interface or a loopback interface of the corresponding LER or LSR router. The IPv6 address can also be set to the system interface IPv6 address. Failure to follow the preceding IPv6 address guidelines for the from, to and hop, commands causes path computation to fail with failure code ‟noCspfRouteToDestination. A Link-Local IPv6 address of a network interface is also not allowed in the hop command of the path used with the IPv6 SR-TE LSP. The configuration fails.

A TE link with no global unicast IPv6 address and only a link local IPv6 address can however be used in the path computation by the local CSPF. The address shown in the ‛Computed Hops’ and in the ‛Actual Hops’ fields of the output of the path show command uses the neighbor’s IPv6 TE router ID and the Link-Local Interface Identifier. The exceptions are if the interface is of type broadcast or is of type point-to-point but also has a local IPv4 address. Only the neighbor’s IPv6 TE router ID is shown as the Link-Local Interface Identifiers sub-TLV is not advertised in these situations.

The global MPLS IPv4 state UP value requires that the system interface be in the admin UP state and to have a valid IPv4 address.

The global MPLS IPv6 state UP value requires that the interface used for the IPv6 TE router ID be in admin UP state and to have a valid preferred primary IPv6 global unicast address.

The TE interface MPLS IPv4 state UP value requires the interface be in the admin UP state in the router context and the global MPLS IPv4 state be in UP state.

The TE interface MPLS IPv6 state UP value requires the interface be in the admin UP state in the router context and the global MPLS IPv6 state be in UP state.