Diffserv traffic engineering compliant backup paths for fast reroute protection in MPLS

1. A Point of Local Repair (PLR) network element comprising one or more ports and circuitry connected thereto for forwarding and control, wherein the circuitry is configured to:

receive a PATH message for a Label Switched Path (LSP) tunnel in a Multiprotocol Label Switching (MPLS) network with a specified DiffServ Traffic Engineering (DSTE) Class Type,

process a FAST_REROUTE object in the PATH message which indicates Facility Bypass is desired,

determine the DSTE Class Type based on the PATH message,

store the DSTE Class Type for the LSP tunnel to ensure a Facility Bypass tunnel used for the LSP tunnel supports the specified DSTE Class Type, and

performing one of

(1) receive a second PATH message for a second LSP tunnel with a second FAST_REROUTE object including a second DSTE Class Type that is the same as the specified DSTE Class Type, and responsive to a failure of the second LSP tunnel, select the Facility Bypass tunnel for one of the LSP tunnel and the second LSP tunnel, and

(2) receive a third PATH message for a third LSP tunnel with a third FAST_REROUTE object including a third DSTE Class Type therein for a different DSTE Class Type than the specified DSTE Class Type, and responsive to a failure of the third LSP tunnel, select a second Facility Bypass tunnel for the third LSP tunnel such that the second Facility Bypass tunnel supports the different specified DSTE Class Type.

2. The PLR network element of claim 1 , wherein the DSTE Class Type is incorporated in the FAST_REROUTE object.

3. The PLR network element of claim 2 , wherein the DSTE Class Type is incorporated in flags in the FAST_REROUTE object.

4. The PLR network element of claim 2 , wherein the DSTE Class Type is incorporated in unspecified flags in the FAST_REROUTE object.

5. The PLR network element of claim 1 , wherein the circuitry is further configured to

responsive to a failure of the LSP tunnel, select the Facility Bypass tunnel for the LSP tunnel such that the Facility Bypass tunnel supports the specified DSTE Class Type.

6. A method, implemented in a Point of Local Repair (PLR) network element, comprising:

receiving a PATH message for a Label Switched Path (LSP) tunnel in a Multiprotocol Label Switching (MPLS) network with a specified DiffSery Traffic Engineering (DSTE) Class Type;

processing a FAST REROUTE object in the PATH message which indicates Facility Bypass is desired;

determining the DSTE Class Type based on the PATH message;

storing the DSTE Class Type for the LSP tunnel to ensure a Facility Bypass tunnel used for the LSP tunnel supports the specified DSTE Class Type; and

performing one of

(1) receiving a second PATH message for a second LSP tunnel with a second FAST_REROUTE object including a second DSTE Class Type that is the same as the specified DSTE Class Type, and responsive to a failure of the second LSP tunnel, selecting the Facility Bypass tunnel for one of the LSP tunnel and the second LSP tunnel, and

(2) receiving a third PATH message for a third LSP tunnel with a third FAST_REROUTE object including a third DSTE Class Type therein for a different DSTE Class Type that the specified DSTE Class Type, and responsive to a failure of the third LSP tunnel, selecting a second Facility Bypass tunnel for the third LSP tunnel such that the second Facility Bypass tunnel supports the different specified DSTE Class Type.

7. The method of claim 6 , wherein the DSTE Class Type is incorporated in the FAST_REROUTE object.

8. The method of claim 7 , wherein the DSTE Class Type is incorporated in flags in the FAST_REROUTE object.

9. The method of claim 7 , wherein the DSTE Class Type is incorporated in unspecified flags in the FAST_REROUTE object.

10. The method of claim 6 , further comprising

responsive to a failure of the LSP tunnel, selecting the Facility Bypass tunnel for the LSP tunnel such that the Facility Bypass tunnel supports the specified DSTE Class Type.

11. A Label Edge Router (LER) network element comprising one or more ports and circuitry connected thereto for forwarding and control, wherein the circuitry is configured to:

transmit a PATH message for a Label Switched Path (LSP) tunnel in a Multiprotocol Label Switching (MPLS) network with a specified DiffSery Traffic Engineering (DSTE) Class Type, wherein a FAST_REROUTE object is included in the PATH message which indicates Facility Bypass is desired, and wherein the DSTE Class Type is based on the PATH message, wherein the DSTE Class Type for the LSP tunnel is stored at a Point of Local Repair (PLR) to ensure a Facility Bypass tunnel used for the LSP tunnel supports the specified DSTE Class Type;

one of

(1) transmit a second PATH message for a second LSP tunnel with a second FAST_REROUTE object including a second DSTE Class Type that is the same as the specified DSTE Class Type, and responsive to a failure of the second LSP tunnel, the PLR is configured to select the Facility Bypass tunnel for one of the LSP tunnel and the second LSP tunnel, and

(2) transmit a third PATH message for a third LSP tunnel with a third FAST_REROUTE object including a third DSTE Class Type therein for a different DSTE Class Type than the specified DSTE Class Type, and responsive to a failure of the third LSP tunnel, the PLR is configured to select a second Facility Bypass tunnel for the third LSP tunnel such that the second Facility Bypass tunnel supports the different specified DSTE Class Type.

12. The LER network element of claim 11 , wherein the DSTE Class Type is incorporated in the FAST_REROUTE object.

13. The LER network element of claim 12 , wherein the DSTE Class Type is incorporated in flags in the FAST_REROUTE object.

14. The LER network element of claim 12 , wherein the DSTE Class Type is incorporated in unspecified flags in the FAST_REROUTE object.