SYSTEM AND METHOD FOR MULTICASTING IN AN INTERNET PROTOCOL VIRTUAL PRIVATE NETWORK ENVIRONMENT

• US 20100054245A1
• Filed: 09/02/2008
• Published: 03/04/2010
• Est. Priority Date: 09/02/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Khalid, Mohamed, Cai, Yiqun, Asati, Rajiv
• Granted Patent: US 7,969,981 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. 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 45/16 Multipoint routing

Abstract

A method is provided in one example implementation and includes sending a PIM join message to the second spoke router by the hub router. The second spoke router dynamically determines each interested remote spoke router by parsing a hub-sent PIM message and accordingly constructs the multicast routing entry such that the first and second spoke routers establish multicast communication independent of a hub router. In more specific embodiments, the PIM join/prune messaging includes a list of each downstream spoke router that sent a PIM join/prune, in a new attribute. The PIM join/prune message is sent by the hub router towards a multicast source. A new receiver-list attribute is created that the hub router populates with a non-broadcast multi-access (NBMA) address for each interested spoke router.

Claims

1. An apparatus, comprising:

a hub router that receives protocol independent multicast (PIM) messages from a first spoke router, whereby the hub router sends one PIM join message to a second spoke router, wherein the second spoke router dynamically determines an interested remote spoke router by parsing a hub-sent PIM message and by constructing a related outgoing interface in a multicast routing entry such that the first and second spoke routers establish a communication independent of the hub router.

2. The apparatus of claim 1, wherein PIM messaging includes a list of each downstream spoke router that sent a PIM message in a new attribute.

3. The apparatus of claim 2, wherein a PIM message is forwarded by the hub router upstream towards a source in a remote spoke site, and wherein a new receiver-list attribute is created that the hub router populates to include a non-broadcast multi-access (NBMA) Internet Protocol (IP) address for each interested spoke router.

4. The apparatus of claim 2, wherein a multicast route entry is provided with the same incoming interface (IIF) and outgoing interface (OIF), whereby multicast traffic is received on a multi-point IP tunnel with Generic Routing Encapsulation (GRE) and is forwarded on a same multi-point IP tunnel.

5. The apparatus of claim 4, wherein the hub router includes two internal virtual private network (VPN) routing/forwarding (VRF) tables to separate received and transmitted traffic.

6. The apparatus of claim 1, wherein the multicast route (mroute) OIF creation at the spoke router is based on a receiver-list attribute information of a received PIM message, whereby the first spoke router updates an outgoing interface for each entry in the receiver-list.

7. The apparatus of claim 1, wherein no spoke router receives traffic directly from another spoke router or some spoke routers receive multicast traffic directly from another spoke router.

8. The apparatus of claim 1, wherein all spoke routers receive multicast traffic directly from another spoke router.

9. The apparatus of claim 1, wherein a selected spoke router, fronting a multicast source, dynamically determines an interested remote spoke router receiver, whereby once an outgoing interface is created, a corresponding IP tunnel with Generic Routing Encapsulation (GRE) is constructed.

10. The apparatus of claim 1, wherein the hub and spoke routers support specific source multicast (SSM) and any source multicast (ASM) usage.

11. The apparatus of claim 1, wherein the hub router appends an attached receiver'"'"'s information in a selected PIM message that is delivered to a remote spoke router, or the hub router directly conveys the selected PIM message to the remote spoke router.

12. A method, comprising:

receiving protocol independent multicast (PIM) messages from a first spoke router, whereby a hub router sends one PIM join message to a second spoke router, wherein the second spoke router dynamically determines an interested remote spoke router by parsing a hub-sent PIM message and by constructing a related outgoing interface in a multicast routing entry such that the first and second spoke routers establish a communication independent of the hub router.

13. The method of claim 12, wherein PIM messaging includes a list of each downstream spoke router that sent a PIM message in a new attribute.

14. The method of claim 13, wherein a PIM message is forwarded by the hub router upstream towards a source in a remote spoke site, and wherein a new receiver-list attribute is created that the hub router populates to include a non-broadcast multi-access (NBMA) Internet Protocol (IP) address for each interested spoke router.

15. The method of claim 13, wherein a multicast route entry is provided with the same incoming interface (IIF) and outgoing interface (OIF), whereby multicast traffic is received on a multi-point IP tunnel with Generic Routing Encapsulation (GRE) and is forwarded on a same multi-point IP tunnel.

16. Logic encoded in one or more tangible media for execution and when executed by a processor operable to:

receive protocol independent multicast (PIM) messages from a first spoke router, whereby a hub router sends one PIM join message to a second spoke router, wherein the second spoke router dynamically determines an interested remote spoke router by parsing a hub-sent PIM message and by constructing a related outgoing interface in a multicast routing entry such that the first and second spoke routers establish a communication independent of the hub router.

17. The logic of claim 16, wherein PIM messaging includes a list of each downstream spoke router that sent a PIM message in a new attribute.

18. The logic of claim 16, wherein the multicast route (mroute) OIF creation at the spoke router is based on a receiver-list attribute information of a received PIM message, whereby the first spoke router updates an outgoing interface for each entry in the receiver-list.

19. The logic of claim 16, wherein a hello message is provided with an option type that conveys an ability to include a receiver list attribute in a PIM message.

20. The logic of claim 16, wherein a selected spoke router, fronting a multicast source, dynamically determines an interested remote spoke router receiver, whereby once an outgoing interface is created, a corresponding IP tunnel with Generic Routing Encapsulation (GRE) is constructed.

21. A system, comprising:

means for receiving protocol independent multicast (PIM) messages from a first spoke router, whereby a hub router sends one PIM join message to a second spoke router, wherein the second spoke router dynamically determines an interested remote spoke router by parsing a hub-sent PIM message and by constructing a related outgoing interface in a multicast routing entry such that the first and second spoke routers establish a communication independent of the hub router; and

means for including, within PIM messaging, a list of each downstream spoke router that sent a PIM message in a new attribute.