Automation fallback to P2P LSPs for mLDP built multipoint-trees

• US 8,107,473 B2
• Filed: 03/16/2006
• Issued: 01/31/2012
• Est. Priority Date: 03/16/2006
• 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): Phillips, Hassan
• Assistant Examiner(s): SWEET, LONNIE V
• Application Number:
  US11/377,063
• Publication Number:
  US 20070217428A1
• Time in Patent Office: 2,147 Days
• Field of Search: 370/390, 370/401, 370/432
• US Class Current: 370/392
• 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. When configuring the P2MP LSP, an mLDP enabled LSR receives a first message from a non-mLDP enabled MPLS core router in response to sending a label mapping message to the non-mLDP enabled MPLS core router. In response, a directed LDP session is created between the mLDP enabled LSR and an edge LSR in one embodiment in response to receiving the first message from an MPLS enabled core router. The directed LDP session can be used to transmit a label mapping message to an ingress LSR.

Claims

1. A method comprising:

a core router receiving a multicast label distribution protocol (LDP) message;

the core router detecting that a multicast LDP session with an edge router cannot be established;

the core router creating a directed LDP session with the edge router in response to the detecting; and

the core router transmitting the multicast LDP message to the edge router via the directed LDP session.

2. The method of claim 1 wherein the multicast LDP message comprises a first value, wherein the first value was generated by a second edge router as a function of a multicast group Internet Protocol (IP) address.

3. The method of claim 2 wherein the first value was generated as a function of a multicast data packet source IP address.

4. The method of claim 3 wherein the multicast LDP message comprises an identity of the edge router.

5. The method of claim 4 wherein the multicast LDP message comprises a label generated by the core router.

16. The method of claim 1 wherein the detecting further comprises the core router receiving a first message comprising an unknown forwarding equivalency class message.

17. The method of claim 1 further comprising

the core router transmitting an identity of the core router to the edge router via the directed LDP session.

6. An apparatus comprising:

a first circuit configured to send a multicast label distribution protocol (LDP) label mapping message to a non-multicast LDP enabled core router;

a second circuit configured to receive a first message from the non-multicast LDP enabled core router in response to the first circuit sending the multicast LDP label mapping message to the non-multicast LDP enabled core router; and

a third circuit configured to send the multicast LDP label mapping message to a first edge router via a directed LDP session in response to the second circuit detecting that a multicast LDP session cannot be established with the edge router, wherein the detecting is based in part on the received first message.

7. The apparatus of claim 6 wherein the multicast LDP label mapping message comprises a first value, wherein the first value is generated by a second edge router as a function of a multicast group Internet Protocol (IP) address.

8. The apparatus of claim 7 wherein the first value is generated as a function of a multicast data packet source IP address.

9. The apparatus of claim 8 wherein the multicast LDP label mapping message comprises an identity of the first edge router.

18. The apparatus of claim 6 further comprising;

a fourth circuit configured to receive a data packet via a point-to-point (P2P) label switched path (LSP);

a fifth circuit configured to replicate the data packet to produce a replicated data packet; and

a sixth circuit configured to send the replicated data packet to a multicast LDP enabled edge router via a point-to-point (P2MP) LSP.

10. A system comprising:

first and second multicast label distribution protocol (LDP) enabled edge routers coupled to each other via a multicast LDP enabled core router and a non-multicast LDP enabled core router;

wherein the first multicast LDP enabled edge router is configured to receive a protocol independent multicast (PIM) Join message;

wherein the multicast LDP enabled core router is configured to receive a message from the non-multicast LDP enabled core router in response to the multicast LDP enabled core router sending a label mapping message to the non-multicast LDP enabled core router;

wherein the multicast LDP enabled core router is configured to create a directed LDP session with the second multicast LDP enabled edge router in response to detecting that a multicast LDP session cannot be established with the second multicast LDP enabled edge router, wherein

the detecting is based in part on the received message; and

wherein the multicast LDP enabled core router is configured to send the label mapping message to the second multicast LDP enabled edge router via the directed LDP session.

11. The system of claim 10 wherein the label mapping message comprises a first value generated by the first multicast LDP enabled edge router, wherein

the first value is generated as a function of a multicast group Internet Protocol (IP) address contained in the PIM Join message.

12. The system of claim 11 wherein the first value is generated as a function of a multicast data packet source IP address contained in the PIM Join message.

13. The system of claim 12 wherein the label mapping message comprises an identity of the second multicast LDP enabled edge router.

14. The system of claim 10 wherein the label mapping message comprises a label generated by the multicast LDP enabled core router.

15. The system of claim 10 wherein the multicast LDP enabled core router is configured to send an identity of the multicast LDP enabled core router to the second multicast LDP enabled edge router via the directed LDP session.

19. A method in a multiprotocol label switched (MPLS) network comprising:

an MPLS enabled core router detecting that a multicast label distribution protocol (LDP) session between the MPLS enabled core router and an MPLS enabled edge router cannot be established because an intervening router is not multicast LDP enabled; and

the MPLS enabled core router creating a directed LDP session between the MPLS enabled core router and the MPLS enabled edge router if the multicast LDP session cannot be established.