MULTICAST STATE REDUCTION VIA TUNNELING IN A ROUTED SYSTEM

• US 20170078188A1
• Filed: 09/10/2015
• Published: 03/16/2017
• Est. Priority Date: 09/10/2015
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: ALLAN, David Ian
• Granted Patent: US 10,673,742 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 51/224 providing notification on incoming messages, e.g. pushed notifications of received messages

Abstract

A method is implemented by a network device in a network including a plurality of network devices. The method implements multicast forwarding configuration resulting in reduced state for the network by utilizing unicast tunneling between a root, replication points and leaves that implement each multicast distribution tree. The method selects a multicast group to determine forwarding configuration for the selected multicast group, prunes a shortest path tree for the selected multicast group to generate a source group tree, and determines whether the network device is a root or a replication node for the source group tree. The method further checks whether a downstream leaf or replicating node is adjacent to the network device, and where the selected branch does not have an adjacent replication node or leaf, identifies the next replicating node or leaf on the selected branch, and configures the network device to forward multicast group traffic using a unicast tunnel.

Claims

1. A method implemented by a network device in a network including a plurality of network devices, the method to implement multicast forwarding configuration utilizing a method resulting in reduced state for the network by utilizing unicast tunneling between a root, replication points and leaves that implement each multicast distribution tree, the method comprising:

selecting a multicast group to determine forwarding configuration for the selected multicast group;

pruning all branches of a shortest path tree rooted at a source node for the selected multicast group that do not serve at least one leaf for the multicast group to generate a source group tree;

determining whether the network device is a root or a replication node for the source group tree;

checking whether a downstream leaf or replicating node is adjacent to the network device; and

where the selected branch does not have an adjacent replication node or leaf,

identifying the next replicating node or leaf on the selected branch, and

configuring the network device to forward multicast group traffic to the identified replicating node or leaf using a unicast tunnel.

2. The method of claim 1, further comprising:

configuring the network device to forward multicast group traffic using the multicast group identifier to the adjacent leaf or replicating node where the network device is a replication node and the leaf or replicating node is adjacent.

3. The method of claim 1, further comprising:

checking whether the network device is a root for the source group tree; and

mapping multicast traffic for distribution in the network to a set of identifiers used to identify (S,G) traffic.

4. The method of claim 1, further comprising:

checking whether the network device is a replication node for the source group tree; and

configuring the network device to handle the multicast group identifier on an upstream interface and to cross connect the ingress multicast identifier with the egress multicast identifier.

5. The method of claim 1, wherein the method is initiated in response to a device startup, an update of the network topology or multicast group membership information.

6. A networking device in a network including a plurality of network devices, the networking device to execute a method to implement multicast forwarding configuration utilizing a method resulting in reduced state for the network by utilizing unicast tunneling between a root, replication points and leaves that implement each multicast distribution tree, the network device comprising:

a non-transitory machine-readable storage device having stored therein a multicast management module; and

a processor coupled to the non-transitory machine-readable storage device, the processor configured to execute the multicast management module, the multicast management module configured to select a multicast group to determine forwarding configuration for the selected multicast group, prune all branches of a shortest path tree rooted at a source node for the selected multicast group that do not serve at least one leaf for the multicast group to generate a source group tree, to determine whether the network device is a root or a replication node for the source group tree, to check whether a downstream leaf or replicating node is adjacent to the network device, and where the selected branch does not have an adjacent replication node or leaf, identifying the next replicating node or leaf on the selected branch, and configuring the network device to forward multicast group traffic to the identified replicating node or leaf using a unicast tunnel.

7. The network device of claim 6, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to configure the network device to forward multicast group traffic using the multicast group identifier to the adjacent leaf or replicating node where the network device is a replication node and the leaf or replicating node is adjacent.

8. The network device of claim 6, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to check whether the network device is a root for the source group tree, and to map multicast traffic for distribution in the network to a set of identifiers used to identify (S,G) traffic.

9. The network device of claim 6, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to check whether the network device is a replication node for the source group tree, and to configure the network device to handle the multicast group identifier on an upstream interface and to cross connect the ingress multicast identifier with the egress multicast identifier.

10. The network device of claim 6, wherein the method is initiated in response to a device startup, an update of the network topology or multicast group membership information.

11. A computing device in communication with a network device in a network with a plurality of network devices, the computing device to execute a plurality of virtual machines for implementing network function virtualization (NFV), wherein a virtual machine from the plurality of virtual machines is configured to implement a method to implement multicast forwarding configuration utilizing the method resulting in reduced state for the network by utilizing unicast tunneling between a root, replication points and leaves that implement each multicast distribution tree, the computing device comprising:

a non-transitory machine-readable storage device having stored therein a multicast management module; and

a processor coupled to the non-transitory machine-readable storage device, the processor configured to execute the virtual machine, the virtual machine configured to execute the multicast management module, the multicast management module configured to select a multicast group to determine forwarding configuration for the selected multicast group, prune all branches of a shortest path tree rooted at a source node for the selected multicast group that do not serve at least one leaf for the multicast group to generate a source group tree, to determine whether the network device is a root or a replication node for the source group tree, to check whether a downstream leaf or replicating node is adjacent to the network device, and where the selected branch does not have an adjacent replication node or leaf,

identifying the next replicating node or leaf on the selected branch, and

configuring the network device to forward multicast group traffic to the identified replicating node or leaf using a unicast tunnel.

12. The computing device of claim 11, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to configure the network device to forward multicast group traffic using the multicast group identifier to the adjacent leaf or replicating node where the network device is a replication node and the leaf or replicating node is adjacent.

13. The computing device of claim 11, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to check whether the network device is a root for the source group tree, and to map multicast traffic for distribution in the network to a set of identifiers used to identify (S,G) traffic.

14. The computing device of claim 11, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to check whether the network device is a replication node for the source group tree, and to configure the network device to handle the multicast group identifier on an upstream interface and to cross connect the ingress multicast identifier with the egress multicast identifier.

15. The computing device of claim 11, wherein the method is initiated in response to a device startup, an update of the network topology or multicast group membership information.

16. A control plane device is configured to implement a control plane of a software defined networking (SDN) network including a network device in a network with a plurality of network devices, wherein the control plane device is configured to implement a method to implement multicast forwarding configuration utilizing the method resulting in reduced state for the network by utilizing unicast tunneling between a root, replication points and leaves that implement each multicast distribution tree, the control plane device comprising:

a non-transitory machine-readable storage device having stored therein a multicast management module; and

a processor coupled to the non-transitory machine-readable storage device, the processor configured to execute the multicast management module, the multicast management module configured to select a multicast group to determine forwarding configuration for the selected multicast group, prune all branches of a shortest path tree rooted at a source node for the selected multicast group that do not serve at least one leaf for the multicast group to generate a source group tree, to determine whether the network device is a root or a replication node for the source group tree, to check whether a downstream leaf or replicating node is adjacent to the network device, and where the selected branch does not have an adjacent replication node or leaf, identifying the next replicating node or leaf on the selected branch, and configuring the network device to forward multicast group traffic to the identified replicating node or leaf using a unicast tunnel.

17. The control plane device of claim 16, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to configure the network device to forward multicast group traffic using the multicast group identifier to the adjacent leaf or replicating node where the network device is a replication node and the leaf or replicating node is adjacent.

18. The control plane device of claim 16, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to check whether the network device is a root for the source group tree, and to map multicast traffic for distribution in the network to a set of identifiers used to identify (S,G) traffic.

19. The control plane device of claim 16, wherein the processor is further configured to execute the multicast management module, the multicast management module configured to check whether the network device is a replication node for the source group tree, and to configure the network device to handle the multicast group identifier on an upstream interface and to cross connect the ingress multicast identifier with the egress multicast identifier.

20. The control plane device of claim 16, wherein the method is initiated in response to a device startup, an update of the network topology or multicast group membership information.