Automation fallback to P2P LSPs for MLDP built multipoint-trees

• US 8,948,170 B2
• Filed: 01/30/2012
• Issued: 02/03/2015
• Est. Priority Date: 11/04/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Wijnands, Ijsbrand, Boers, Arjen, Meylor, John S.
• Primary Examiner(s): Smith, Marcus R
• Assistant Examiner(s): SWEET, LONNIE V
• Application Number:
  US13/361,137
• Publication Number:
  US 20120195312A1
• Time in Patent Office: 1,100 Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/1845 broadcast or multicast in a specific location, e.g. geocast protocols for adapting network applications to user terminal location H04L67/52; services specially adapted for wireless communication networks making use of the location of users or terminals H04W4/02
• CPC Class Codes: H04L 2012/5641 Unicast/point-to-point
• CPC Class Codes: H04L 2012/5642 Multicast/broadcast/point-multipoint, e.g. VOD
• CPC Class Codes: H04L 2012/6416 Switch multicast
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/46 Cluster building
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 45/502 Frame based

Abstract

A method of using a point-to-point (P2P) label switched path (LSP) to transmit multicast data packets partially through a multiprotocol label switched (MPLS) network when one or more label switched routers (LSRs) of the MPLS are not multicast label distribution protocol (mLDP) enabled. The P2P LSP can be used to transmit multicast data packets to the head end of a point-to-multipoint (P2MP) LSP created with mLDP enabled LSRs. The P2MP LSP can be used to transmit the multicast data packets through the MPLS network to intended receivers that are external to the MPLS network. The P2MP LSP can be built from an egress edge LSR towards an ingress edge LSR, by mLDP enabled LSRs. The P2P LSP can be built from a core mLDP enabled LSR to the ingress edge LSR, across a non-mLDP enabled LSR between the core mLDP enabled LSR and the ingress edge LSR.

Claims

1. A method comprising:

a core router receiving a stacked label multicast packet from a first edge router via a point-to-point label switched path (LSP), wherein

the stacked label multicast packet comprises

a multicast packet,

a top label associated with the point-to-point LSP, and

a bottom label associated with a point-to-multipoint LSP;

selecting whether to pop or swap the top label from the stacked label multicast packet, wherein the selecting comprises;

the core router popping the top label from the stacked label multicast packet to produce a labeled multicast packet, if the core router is the penultimate router of the point-to-point LSP from the first edge router to an ultimate router;

the core router swapping the top label for a new top label to produce the labeled multicast packet, if the core router is not the penultimate router; and

the core router transmitting the labeled multicast packet to a second edge router via the point-to-multipoint LSP.

2. The method of claim 1, wherein

the point-to-point LSP comprises a non multicast label distribution protocol (non-mLDP) enabled core router, and

the point-to-multipoint LSP comprises mLDP enabled core routers.

3. The method of claim 1, wherein

the core router transmits the labeled multicast packet to a next core router that comprises both a tail end router of the point-to-point LSP and a head end router of the point-to-multipoint LSP,

the point-to-point LSP is established between the first edge router and the next core router, and

the point-to-multipoint LSP is established between the next core router and the second edge router.

4. The method of claim 3, further comprising:

the next core router replicating the multicast packet to produce a replicated data packet; and

the next core router transmitting the replicated data packet to a third edge router via the point-to-multipoint LSP.

5. The method of claim 1, wherein

the bottom label is associated with a multicast forwarding equivalence class (mFEC),

the second edge router is multicast label distribution protocol (mLDP) enabled, and

the second edge router generated the mFEC.

6. The method of claim 5, wherein

the multicast packet comprises a source address and a multicast group address, and

the mFEC comprises an opaque value generated as a function of the source address and the multicast group address.

7. The method of claim 6, wherein

the core router is not mLDP enabled, and

the core router does not recognize the mFEC.

8. A system comprising:

first and second edge routers coupled to each other via a core router; and

the core router configured to

receive a stacked label multicast packet from the first edge router via a point-to-point label switched path (LSP), wherein

the stacked label multicast packet comprises

a multicast packet,

a top label associated with the point-to-point LSP, and

a bottom label associated with a point-to-multipoint LSP;

select whether to pop or swap the top label from the stacked label multicast packet, wherein selecting whether to pop or swap comprises;

popping the top label from the stacked label multicast packet to produce a labeled multicast packet, if the core router is the penultimate router of the point-to-point LSP from the first edge router to an ultimate router, or swapping the top label for a new top label to produce the labeled multicast packet, if the core router is not the penultimate router, and

transmit the labeled multicast packet to the second edge router via the point-to-multipoint LSP.

9. The system of claim 8, wherein

the point-to-point LSP comprises a non multicast label distribution protocol (non-mLDP) enabled core router, and

the point-to-multipoint LSP comprises mLDP enabled core routers.

10. The system of claim 8, wherein

the core router transmits the labeled multicast packet to a next core router that comprises both a tail end router of the point-to-point LSP and a head end router of the point-to-multipoint LSP,

the point-to-point LSP is established between the first edge router and the next core router, and

the point-to-multipoint LSP is established between the next core router and the second edge router.

11. The system of claim 10, further comprising the next core router, wherein

the next core router is configured to

replicate the multicast packet to produce a replicated data packet, and

transmit the replicated data packet to the second edge router via the point-to-multipoint LSP.

12. The system of claim 8, wherein

the bottom label is associated with a multicast forwarding equivalence class (mFEC),

the second edge router is multicast label distribution protocol (mLDP) enabled, and

the second edge router generated the mFEC.

13. The system of claim 12, wherein

the multicast packet comprises a source address and a multicast group address, and

the mFEC comprises an opaque value generated as a function of the source address and the multicast group address.

14. The system of claim 13, wherein

the core router is not mLDP enabled, and

the core router does not recognize the mFEC.

15. An apparatus comprising:

a core router comprising a first circuit, a second circuit, and a third circuit, wherein;

the first circuit configured to receive a stacked label multicast packet from a first edge device via a point-to-point label switched path (LSP), wherein

the stacked label multicast packet comprises

a multicast packet,

a top label associated with the point-to-point LSP, and

a bottom label associated with a point-to-multipoint LSP;

the second circuit configured to select whether to pop or swap the top label from the stacked label multicast packet, wherein selecting whether to pop or swap comprises;

popping the top label from the stacked label multicast packet to produce a labeled multicast packet, if the core router is the penultimate router of the point-to-point LSP from the first edge router to an ultimate router, or swapping the top label for a new top label to produce the labeled multicast packet, if the core router is not the penultimate router; and

the third circuit configured to transmit the labeled multicast packet to a second edge device via the point-to-multipoint LSP.

16. The apparatus of claim 15, wherein

the third circuit is configured to transmit the labeled multicast packet to a next core apparatus that comprises both a tail end device of the point-to-point LSP and a head end device of the point-to-multipoint LSP,

the point-to-point LSP is established between the first edge device and the next core apparatus, and

the point-to-multipoint LSP is established between the next core apparatus and the second edge device.

17. The apparatus of claim 16, wherein

the bottom label is associated with a multicast forwarding equivalence class (mFEC),

the second edge router is multicast label distribution protocol (mLDP) enabled, and

the second edge router generated the mFEC.

18. The apparatus of claim 17, wherein

the multicast packet comprises a source address and a multicast group address, and

the mFEC comprises an opaque value generated as a function of the source address and the multicast group address.

19. The apparatus of claim 18, wherein

the apparatus is not mLDP enabled, and

the apparatus does not recognize the mFEC.