Auto-discovery of multicast virtual private networks

• US 8,160,076 B1
• Filed: 08/26/2005
• Issued: 04/17/2012
• Est. Priority Date: 08/30/2004
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Aggarwal, Rahul, Rekhter, Yakov
• Primary Examiner(s): Banks Harold, Marsha D
• Assistant Examiner(s): Wyllie, Christopher
• Application Number:
  US11/213,640
• Time in Patent Office: 2,426 Days
• Field of Search: 370/432, 370/390, 370/489, 370/389, 370/401, 370/400, 370/428, 370/395.1, 709/225, 709/227, 709/237, 709/238, 709/223, 709/232, 709/163, 713/163
• US Class Current: 370/395.5
• 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:

discovering multicast virtual private network (MVPN) memberships of a plurality of destination routers within a network, wherein each of the plurality of destination routers is coupled to one or more respective customer networks and belongs to at least one of a plurality of different MVPNs, and wherein discovering the MVPN memberships of the destination routers includes receiving Border Gateway Protocol (BGP) advertisements from each of the destination routers that specify virtual routing and forwarding (VRF) instances configured on the destination routers for the different MVPNs to which the respective destination router belongs;

allocating, with the source router, a label for receiving control information from the plurality of destination routers and sending Border Gateway Protocol (BGP) advertisements from the source router to the plurality of destination routers to advertise the label to the plurality of destination routers;

after discovering the MVPN memberships, establishing a multicast tree within the network for at least one of the discovered MVPNs, the multicast tree comprising a point-to-multipoint (P2MP) label switched path (LSP) forming a tunnel for transporting multicast data packets from a source router providing an ingress to the P2MP LSP to the plurality of destination routers providing a plurality of different egresses from the P2MP LSP;

receiving BGP advertisements that encode multicast group join or prune messages as the control information for one or more of the MVPNs using the label allocated by the source router; and

transmitting multicast data packets for the MVPNs from the source router through the P2MP LSP to the plurality of destination devices on the multicast tree in accordance with the control information.

2. The method of claim 1, where the multicast tree comprises one of a resource reservation protocol (RSVP) tree or a label distribution protocol (LDP) tree.

3. The method of claim 1, further comprising including a route target attribute of each of the discovered MVPNs in the BGP advertisements.

4. A method comprising:

discovering multicast virtual private network (MVPN) memberships of a plurality of destination routers within a network, wherein each of the plurality of destination routers is coupled to one or more respective customer networks and belongs to at least one of a plurality of different MVPNs, and wherein discovering the MVPN memberships of the destination routers includes receiving Border Gateway Protocol (BGP) advertisements from each of the destination routers that specify virtual routing and forwarding (VRF) instances configured on the destination routers for the different MVPNs to which the respective destination router belongs;

after discovering the MVPN memberships, establishing a multicast tree within the network for at least one of the discovered MVPNs, the multicast tree comprising a point-to-multipoint (P2MP) label switched path (LSP) forming a tunnel for transporting multicast data packets from a source router providing an ingress to the P2MP LSP to the plurality of destination routers providing a plurality of different egresses from the P2MP LSP;

after establishing the multicast tree within the network, receiving additional BGP advertisements from the destination routers and maintaining protocol independent multicast (PIM) neighbor adjacencies between the source device and the one or more destination routers that belong to the same MVPNs based on the additional BGP advertisements; and

transmitting multicast data packets for the MVPNs from the source router through the P2MP LSP to the plurality of destination devices on the multicast tree in accordance with the control information.

5. A network router comprising:

an auto-discovery module that discovers multicast virtual private network (MVPN) memberships of a plurality of destination routers within a network, wherein each of the plurality of destination routers is coupled to one or more respective customer networks and belongs to at least one of a plurality of different MVPNs, wherein the auto-discovery module receives Border Gateway Protocol (BGP) advertisements from each of the destination routers that specify virtual routing and forwarding (VRF) instances configured on the destination routers for the different MVPNs to which the respective destination router belongs, wherein the auto-discovery module maintains protocol independent multicast (PIM) neighbor adjacencies between the source router and the one or more destination routers that belong to the same MVPNs with the BGP advertisements; and

a control unit that executes a label switching protocol to establish a multicast tree within the network for at least one of the discovered MVPNs, the multicast tree comprising a point-to-multipoint (P2MP) label switched path (LSP) forming a tunnel for transporting multicast data packets from a source device providing an ingress to the multicast tree to the plurality of destination routers providing a plurality of different egresses from the multicast tree.

6. The network router of claim 5, where the multicast tree comprises one of a resource reservation protocol (RSVP) tree or a protocol independent multicast (PIM) tree.

7. The network router of claim 5, wherein the auto-discovery module advertises MVPN memberships of the source router to the one or more destination routers.

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

discover multicast virtual private network (MVPN) memberships of a plurality of destination routers within a network, wherein each of the plurality of destination routers is coupled to one or more respective customer networks and belongs to at least one of a plurality of different MVPNs, and wherein discovering the MVPN memberships of the destination devices includes receiving Border Gateway Protocol (BGP) advertisements from each of the destination routers that specify virtual routing and forwarding (VRF) instances configured on the destination routers for the different MVPNs to which the respective destination router belongs;

maintain protocol independent multicast (PIM) neighbor adjacencies between the source router and the plurality of destination router that belong to the same MVPNs with the BGP advertisements; and

establish a multicast tree within the network for at least one of the discovered MVPNs, the multicast tree comprising a point-to-multipoint (P2MP) label switched path (LSP) forming a tunnel for transporting multicast data packets from a source router providing an ingress to the P2MP LSP to the plurality of destination router providing a plurality of different egresses from the P2MP LSP.

9. The non-transitory computer-readable medium of claim 8, further comprising instructions that cause the programmable processor to advertise MVPN memberships of the source router to the plurality of destination routers.

10. The non-transitory computer-readable medium of claim 9, further comprising instructions that cause the programmable processor to advertise the MVPN memberships as Border Gateway Protocol (BGP) advertisements.

11. A system comprising:

a plurality of destination devices within a network that advertise their multicast virtual private network (MVPN) memberships;

a source device within the network that discovers the MVPN memberships of the plurality of destination by receiving Border Gateway Protocol (BGP) advertisements from each of the destination devices that specify virtual routing and forwarding (VRF) instances configured on the destination devices for the different MVPNs to which the respective destination device belongs, wherein the source device maintains protocol independent multicast (PIM) neighbor adjacencies with the plurality of destination router that belong to the same MVPNs with the BGP advertisements; and

a multicast tree established within the network for at least one of the discovered MVPNs from the source device to the plurality of destination devices, wherein the multicast tree comprising a point-to-multipoint (P2MP) label switched path (LSP) forming a tunnel for transporting multicast data packets from the source device as an ingress to the multicast tree to the plurality of destination devices providing a plurality of different egresses from the multicast tree.

12. A method comprising:

discovering multicast virtual private network (MVPN) memberships of a plurality of routers within a network, wherein the plurality of routers include a source router and a plurality of destination routers coupled to one or more respective customer networks, and wherein discovering the MVPN memberships includes communicating Border Gateway Protocol (BGP) advertisements from each of the routers that specify virtual routing and forwarding (VRF) instances configured on the routers for the different MVPNs to which the respective router belongs, wherein the BGP advertisements specify labels that identify the MVPNs to which the respective router belongs for use by the other routers when subsequently sending join/prune messages with respect to the MVPNs;

after discovering the MVPN memberships, establishing a multicast tree within the network for at least one of the discovered MVPNs, the multicast tree comprising a point-to-multipoint (P2MP) label switched path (LSP) forming a tunnel for transporting multicast data packets from the source router providing an ingress to the P2MP LSP to the plurality of destination routers providing a plurality of different egresses from the P2MP LSP;

receiving BGP advertisements that encode multicast group join or prune messages as control information for one or more of the MVPNs; and

transmitting multicast data packets for the MVPNs from the source router through the P2MP LSP to the plurality of destination devices on the multicast tree in accordance with the control information.