Bidirectional multicast protocol with upstream and downstream join messages
First Claim
1. A method comprising:
- receiving a multicast packet addressed to multicast group G via a first interface, whereinmulticast routing for the multicast group G is performed using a modified version of a bidirectional multicast routing protocol, andin an unmodified version of the bidirectional multicast routing protocol, all multicast packets for the multicast group G are automatically forwarded via an interface leading towards a rendezvous point for the multicast group G;
determining whether a join message has been received from a first receiver via a Reverse Path Forwarding (RPF) interface, whereinthe determining is performing using (*, G) state information for the multicast group G,the (*,G) state information for the multicast group G comprises an outgoing interface list, andthe RPF interface is an interface used to send packets towards the rendezvous point for the multicast group G; and
inhibiting the multicast packet from being automatically forwarded via the RPF interface, unless the determining indicates that the join message has been received from the first receiver via the RPF interface, whereinthe first interface is not the interface leading towards the rendezvous point.
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Abstract
Systems and methods for implementing a bidirectional multicast protocol with two types of join messages are disclosed. The two types of join messages, upstream joins and downstream joins, are used to control the Reverse Path Forwarding (RPF) interface is added to the outgoing interface list for a particular multicast group, which in turn controls when multicast packets will be forwarded to the rendezvous point. One method involves receiving a multicast packet addressed to multicast group G. The method inhibits the multicast packet from being forwarded via the RPF interface, unless the outgoing interface list corresponding to the multicast group G already identifies the RPF interface. The RPF interface can be added to the outgoing interface list in response to reception of a downstream join message via the RPF interface, as well as in response to monitoring, via the RPF interface, an upstream join message on a shared network segment.
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Citations
19 Claims
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1. A method comprising:
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receiving a multicast packet addressed to multicast group G via a first interface, wherein multicast routing for the multicast group G is performed using a modified version of a bidirectional multicast routing protocol, and in an unmodified version of the bidirectional multicast routing protocol, all multicast packets for the multicast group G are automatically forwarded via an interface leading towards a rendezvous point for the multicast group G; determining whether a join message has been received from a first receiver via a Reverse Path Forwarding (RPF) interface, wherein the determining is performing using (*, G) state information for the multicast group G, the (*,G) state information for the multicast group G comprises an outgoing interface list, and the RPF interface is an interface used to send packets towards the rendezvous point for the multicast group G; and inhibiting the multicast packet from being automatically forwarded via the RPF interface, unless the determining indicates that the join message has been received from the first receiver via the RPF interface, wherein the first interface is not the interface leading towards the rendezvous point. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A node comprising:
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an interface, wherein the interface is configured to receive a multicast packet addressed to multicast group G, multicast routing for the multicast group G is performed using a modified version of a bidirectional multicast routing protocol, and in an unmodified version of the bidirectional multicast routing protocol, all multicast packets for the multicast group G are automatically forwarded via an interface leading towards a rendezvous point for the multicast group G; a Reverse Path Forwarding (RPF) interface coupled to send packets towards the rendezvous point for the multicast group G; and a bidirectional multicast routing module coupled to the interface and the RPF interface, wherein the bidirectional multicast routing module is configured to determine whether a join message has been received from a first receiver via the RPF interface, wherein the determine is performed using (*, G) state information for the multicast group G, and the (*,G) state information for the multicast group G comprises an outgoing interface list, and the bidirectional multicast routing module is further configured to inhibit the multicast packet from being automatically forwarded via the RPF interface, unless a determination is made that the join message has been received from the first receiver via the RPF interface. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A system comprising:
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means for receiving a multicast packet addressed to multicast group G via a first interface, wherein multicast routing for the multicast group G is performed using a modified version of a bidirectional multicast routing protocol, and in an unmodified version of the bidirectional multicast routing protocol, all multicast packets for the multicast group G are automatically forwarded via an interface leading towards a rendezvous point for the multicast group G; means for determining whether a join message has been received from a first receiver via a Reverse Path Forwarding (RPF) interface, wherein the determining is performing using (*, G) state information for the multicast group G, the (*,G) state information for the multicast group G comprises an outgoing interface list, and the RPF interface is an interface used to send packets towards the rendezvous point for the multicast group G; and means for inhibiting the multicast packet from being automatically forwarded via the RPF interface, unless the determining indicates that the join message has been received from the first receiver via the RPF interface, wherein the first interface is not the interface leading towards the rendezvous point. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification