Inter-autonomous system (AS) multicast virtual private networks

• US 7,957,386 B1
• Filed: 04/14/2009
• Issued: 06/07/2011
• Est. Priority Date: 08/30/2004
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Rekhter, Yakov, Aggarwal, Rahul
• Primary Examiner(s): Cho; Hong
• Application Number:
  US12/423,640
• Time in Patent Office: 784 Days
• Field of Search: 370252-256, 370/338, 370/389, 370/390, 370/392, 370/400, 370/401
• US Class Current: 370/392
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272

Abstract

Principles of the invention are described for providing multicast virtual private networks (MVPNs) across a public network that are capable of carrying high-bandwidth multicast traffic with increased scalability. In particular, the MVPNs may transport layer three (L3) multicast traffic, such as Internet Protocol (IP) packets, between remote sites via the public network. The principles described herein may reduce the overhead of protocol independent multicast (PIM) neighbor adjacencies and customer control information maintained for MVPNs. The principles may also reduce the state and the overhead of maintaining the state in the network by removing the need to maintain at least one dedicated multicast tree per each MVPN.

Claims

1. A method comprising:

establishing a first multicast tree having a source device and one or more destination devices within a first autonomous system (AS), wherein each of the one or more destination devices belongs to at least one multicast virtual private network (MVPN);

establishing a second multicast tree having a source device and one or more destination devices within a second AS, wherein each of the one or more destination devices belongs to at least one MVPN; and

stitching the first and second multicast trees together to create an inter-AS multicast tree that transmits multicast data packets for the MVPNs from the source devices to the destination devices in the first AS and the second AS.

2. The method of claim 1, further comprising:

discovering MVPN memberships of the destination devices in the first AS and the second AS;

mapping at least one of the discovered MVPNs to the inter-AS multicast tree; and

advertising mapping information to the destination devices in the first AS and the second AS.

3. The method of claim 2, further comprising allocating an inner label for each of the MVPNs mapped to the inter-AS multicast tree that identifies the MVPN.

4. The method of claim 2, further comprising determining which of the discovered MVPNs to aggregate onto the inter-AS multicast tree.

5. The method of claim 2, wherein discovering the MVPN memberships comprises discovering virtual routing and forwarding (VRF) instances configured for multicast of the destination devices in the first AS and the second AS.

6. The method of claim 1, further comprising:

receiving mapping information from one of the source devices of the inter-AS multicast tree;

associating the inter-AS multicast tree with one or more of the MVPNs to which the destination device belongs; and

creating a forwarding entry in the destination device that corresponds to the inter-AS multicast tree.

7. The method of claim 6, further comprising creating a logical interface to a label space within the destination device that corresponds to the inter-AS multicast tree.

8. The method of claim 1, wherein transmitting multicast data packets comprises:

receiving the multicast data packets from a multicast source;

encapsulating the multicast data packets for the MVPNs that have destination devices in the first AS and the second AS requesting the multicast data packets; and

transmitting the encapsulated packet for the MVPNs on the inter-AS multicast tree.

9. The method of claim 1, further comprising:

receiving the multicast data packets from one of the source devices of the inter-AS multicast tree; and

sending the multicast data packets to a virtual routing and forwarding (VRF) of the destination device that corresponds to the MVPN for which the multicast data packets were intended based on an inner label allocated by the one of the source devices that identifies the MVPN.

10. The method of claim 1, wherein the inter-AS multicast tree transmits multicast data packets of specific multicast groups that belong to the MVPNs from the source device to the destination devices in the first AS and the second AS.

11. The method of claim 1, wherein the first multicast tree supports a different tunneling protocol than the second multicast tree.

12. The method of claim 1,

wherein the first multicast tree includes a plurality of destination devices within the first autonomous system (AS) and comprises an intra-AS point-to-multipoint (P2MP) label switched path (LSP), and

wherein the second multicast tree includes a plurality of destination devices within a second AS and comprises an intra-AS P2MP LSP.

13. A network device comprising a control unit that:

establishes a first multicast tree having a source device and one or more destination devices within a first autonomous system (AS), wherein each of the one or more destination devices belongs to at least one multicast virtual private network (MVPN);

establishes a second multicast tree having a source device and one or more destination devices within a second AS, wherein each of the one or more destination devices belongs to at least one MVPN; and

stitches the first and second multicast trees together to create an inter-AS multicast tree that transmits multicast data packets for the MVPNs from the source devices to the destination devices in the first AS and the second AS.

14. The network device of claim 13, further comprising:

an auto-discovery module within the control unit that discovers MVPN memberships of the destination devices in the first AS and the second AS; and

a binding module within the control unit that maps at least one of the discovered MVPNs to the inter-AS multicast tree and advertises mapping information to the destination devices in the first AS and the second AS.

15. The network device of claim 14, wherein the control unit allocates an inner label for each of the MVPNs mapped to the inter-AS multicast tree that identifies the MVPN.

16. The network device of claim 14, further comprising an aggregation module that determines which of the discovered MVPNs to aggregate onto the inter-AS multicast tree.

17. The network device of claim 14, wherein the auto-discovery module discovers virtual routing and forwarding (VRF) instances configured for multicast of the destination devices in the first AS and the second AS.

18. The network device of claim 13, wherein the control unit:

receives mapping information from one of the source devices of the inter-AS multicast tree;

associates the inter-AS multicast tree with one or more of the MVPNs to which the destination device belongs; and

creates a forwarding entry in the destination device that corresponds to the inter-AS multicast tree.

19. The network device of claim 18, wherein the control unit creates a logical interface to a label space within the destination device that corresponds to the inter-AS multicast tree.

20. The network device of claim 13, wherein the control unit:

receives the multicast data packets from a multicast source;

encapsulates the multicast data packets for the MVPNs that have destination devices in the first AS and the second AS requesting the multicast data packets; and

transmits the encapsulated packet for the MVPNs on the inter-AS multicast tree.

21. The network device of claim 13, wherein the control unit:

receives the multicast data packets from one of the source devices of the inter-AS multicast tree; and

sends the multicast data packets to a virtual routing and forwarding (VRF) of the destination device that corresponds to the MVPN for which the multicast data packets were intended based on an inner label allocated by the one of the source devices that identifies the MVPN.

22. The network device of claim 13, wherein the inter-AS multicast tree transmits multicast data packets of specific multicast groups that belong to the MVPNs from the source device to the destination devices in the first AS and the second AS.

23. The network device of claim 13, wherein the first multicast tree supports a different tunneling protocol than the second multicast trees.

24. A non-transitory computer-readable medium comprising instructions stored thereon that cause a programmable processor to:

establish a first multicast tree having a source device and one or more destination devices within a first autonomous system (AS), wherein each of the one or more destination devices belongs to at least one multicast virtual private network (MVPN);

establish a second multicast tree having a source device and one or more destination devices within a second AS, wherein each of the one or more destination devices belongs to at least one MVPN; and

stitch the first and second multicast trees together to create an inter-AS multicast tree that transmits multicast data packets for the MVPNs from the source devices to the destination devices in the first AS and the second AS.

25. A system comprising:

a first multicast tree established within a first autonomous system (AS) from a source device to one or more destination devices, wherein each of the one or more destination devices belongs to at least one multicast virtual private network (MVPN);

a second multicast tree established within a second AS from a source device to one or more destination devices, wherein each of the one or more destination devices belongs to at least one MVPN; and

an inter-AS multicast tree created by stitching the first and second multicast trees together, wherein the inter-AS multicast tree transmits multicast data packets for the MVPNs from the source devices to the destination devices in the first AS and the second AS.