Exchange of control information for virtual private local area network (LAN) service multicast

• US 7,990,963 B1
• Filed: 05/20/2009
• Issued: 08/02/2011
• 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): Sheikh; Ayaz R
• Assistant Examiner(s): Vu; Hoang-Chuong Q
• Application Number:
  US12/469,075
• Time in Patent Office: 804 Days
• Field of Search: 370/390, 370/432, 370/395.5, 370/466, 370/467, 709/230
• US Class Current: 370/390
• 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 virtual private local area network service (VPLS) multicast instances across a public network by utilizing multicast trees. In particular, the VPLS multicast instances transport layer two (L2) multicast traffic, such as Ethernet packets, between customer networks via the public network. The principles described herein enable VPLS multicast instances to handle high bandwidth multicast traffic. The principles also reduce the state and the overhead of maintaining the state in the network by removing the need to perform snooping between routers within the network.

Claims

1. A method comprising:

using a label distribution protocol, establishing a point-to-multipoint (P2MP) label switched path (LSP) forming a multicast tree for transporting layer two (L2) multicast data packets for one or more virtual private local area network service (VPLS) multicast instances, wherein the multicast tree includes a source router providing an ingress to the P2MP LSP and a plurality of destination routers providing egresses from the P2MP LSP, wherein each of the one or more destination routers is coupled to one or more respective customer networks having local VPLS sites and belongs to at least one VPLS multicast instance;

receiving with the destination routers multicast group join or prune messages from at least one of the customer networks and destined for the source router of the P2MP LSP in accordance with a multicast group management protocol;

converting with the destination routers the multicast group join or prune messages into border gateway protocol (BGP) routing protocol advertisements by generating the BGP routing protocol advertisements in accordance with the BGP routing protocol and encoding the join or prune messages within network layer reachability information (NLRI) of the BGP routing protocol advertisements as control information for the VPLS multicast instances; and

transmitting the encoded BGP routing protocol advertisements via the BGP routing protocol to communicate the join or prune messages from the destination routers to the source router of the P2MP LSP.

11. The method of claim 1, further comprising

maintaining next hop data with the BGP routing protocol of the destination routers, where the next hop data indicates neighboring routers of the destination routers along routes within a network;

and

forwarding packets with the destination routers in accordance with the next hop data.

2. The method of 1, wherein encoding the multicast group join or prune messages comprises encoding in the NLRI information of the BGP routing protocol advertisement a route distinguisher that corresponds to the VPLS to which each multicast group specified in the multicast group join or prune message belongs, an address of a multicast source associated with each of the multicast groups, and an address of each of the multicast groups.

3. The method of 2, further comprising encoding in the BGP routing protocol advertisement a route target attribute of each of the VPLS multicast instances mapped to the multicast tree.

4. The method of 1, wherein establishing the P2MP LSP comprises:

allocating an outer label for the P2MP LSP with the label distribution protocol;

allocating, with the source router, an inner label for each multicast customer source-group mapped to the multicast tree; and

communicating the allocated inner labels from the source router to the destination routers to allow the destination routers to demultiplex the multicast data packets received over the P2MP LSP for the different multicast source-groups.

5. The method of 1, wherein encoding the join or prune messages within the BGP routing protocol advertisements comprises including in the BGP routing protocol advertisement the corresponding inner label allocated by the source of the P2MP LSP for the multicast source-group that is specified by the multicast group join or prune messages.

6. The method of 1, further comprising:

establishing tunnels between the source router and the one or more destination routers; and

using the routing protocol to transmit the encoded BGP routing protocol advertisements on the tunnels.

7. The method of 1, wherein transmitting the encoded BGP routing protocol advertisements comprises transmitting the encoded BGP routing protocol advertisements between remotely located virtual switch interfaces (VSIs) that exist on the destination routers and the source router, wherein the remotely located VSIs correspond to the VPLS multicast instances.

8. The method of 1, wherein receiving the multicast group join or prune messages comprises snooping, with the destination routers, multicast communications received from the customer networks and destined for the source router of the P2MP LSP without snooping multicast communications between the destination routers and the source router.

9. The method of 8, wherein the snooping comprises snooping with a protocol independent multicast (PIM) snooping mechanism to snoop PIM multicast group join or prune messages.

10. The method of 8, wherein the snooping comprises snooping with an internet group management protocol (IGMP) snooping mechanism to snoop IGMP multicast group join or prune messages.

12. A router comprising:

one or more network interfaces;

a control unit coupled to the network interfaces;

a label distribution protocol executing on the control unit that establishes a point-to-multipoint (P2MP) label switched path (LSP) forming a multicast tree for transporting layer two (L2) multicast data packets for one or more virtual private local area network service (VPLS) multicast instances, wherein the P2MP LSP includes a source router providing an ingress to the multicast tree and one or more destination routers providing egresses from the P2MP LSP, wherein each of the destination routers is coupled to one or more respective customer networks having local VPLS sites and belongs to at least one VPLS multicast instance;

a snooping module that snoops multicast control messages between at least one of the destination routers and network devices of the customer networks, wherein the multicast control messages conform to a multicast group management protocol; and

a device-device exchange module within the control unit that converts the multicast control messages into border gateway protocol (BGP) routing protocol advertisements different from the multicast group management protocol and encodes the multicast control messages within network layer reachability information (NLRI) of the BGP messages,

wherein the device-device exchange module transmits the encoded BGP routing protocol advertisements from the destination routers to the source router via the BGP routing protocol to communicate the multicast control messages to the source router of the multicast tree.

13. The router of claim 12, further comprising:

a plurality of different virtual switch interfaces (VSIs), each of the VSIs corresponding to a different one of the VPLS multicast instances,

wherein the device-device exchange module transmits each of the encoded BGP routing protocol advertisements from the VSI that corresponds to the VPLS multicast instances for which the control information is encoded within the BGP routing protocol advertisements.

14. The router of claim 12, further comprising a device-customer snooping module that snoops multicast communications received from the customer networks and destined for the source router of the P2MP LSP without snooping multicast communications between the destination routers and the source router.

15. The network device of 14, wherein the device-customer snooping module discovers control information from locally located virtual switch interfaces (VSIs) of the source router that correspond to the VPLS multicast instances.

16. The network device of 12, wherein the snooping mechanism comprises one of a protocol independent multicast (PIM) snooping mechanism or an internet group management protocol (IGMP) snooping mechanism.

17. A non-transitory computer-readable storage medium comprising program code that cause a programmable processor to:

use a label distribution protocol to establish a multicast tree for transporting layer two (L2) multicast data packets for one or more virtual private local area network service (VPLS) multicast instances, wherein the multicast tree includes a source router providing an ingress to the P2MP LSP and a plurality of destination routers providing egresses from the P2MP LSP, wherein each of the one or more destination routers is coupled to one or more respective customer networks having local VPLS sites and belongs to at least one VPLS multicast instance;

after establishing the P2MP LSP, receiving with one or more of the destination routers multicast group join or prune messages from at least one of the customer networks and destined for the source router of the P2MP LSP in accordance with a multicast group management protocol;

converting the multicast group join or prune messages into border gateway protocol (BGP) routing protocol advertisements by generating the BGP routing protocol advertisements in accordance with the BGP routing protocol and encoding the join or prune messages within network layer reachability information (NLRI) of the BGP routing protocol advertisements; and

transmitting the encoded BGP routing protocol advertisements via the routing protocol to communicate the join or prune messages from the destination routers to the source router of the P2MP LSR.

18. A system comprising:

a source router within a network;

one or more destination routers within the network, wherein each of the destination routers is coupled to one or more respective customer networks having local VPLS sites and belongs to at least one virtual private local area network service (VPLS) multicast instance, and wherein the destination routers receive multicast control messages in the form of join or prune messages from the customer networks in accordance with a multicast group management protocol;

a point-to-multipoint label switched path (LSP) forming a multicast tree within the network from the source router to the one or more destination routers, wherein the source router provides an ingress to the P2MP LSP and each of the destination routers provide a different egress to the P2MP LSP; and

wherein the source router and the one or more destination routers execute the Border Gateway Protocol different from the multicast group management protocol and exchange BGP routing protocol advertisements that encode the join or prune messages within network layer reachability information (NLRI) of the BGP messages as control information for the VLPS multicast instances,

wherein the source router maintains a database for the multicast tree, the database having entries that indicate the VPLS multicast instances to which each of the destination routers belongs based on the join or prune messages received via the BGP routing protocol advertisements.