System, device, and method of dense-mode multicast tunneling using interlayer group membership control

Patent metadata

Field	Value
Publication number	US-9729430-B2
Application number	US-201514692015-A
Country	US
Kind code	B2
Filing date	Apr 21, 2015
Priority date	Apr 21, 2015
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A system, device, and method are provided to control dense-mode multicast traffic across a multilayer system containing an upper network and a tunnel across a lower network. An upstream multicast tunneling edge device (MTED) may indicate to downstream MTEDs, via control messages, the presence of a multicast source, group (SG) pair. The MTEDs may serve as routers or as intelligent bridges in the upper network. Each downstream MTED may create a forwarding state for the SG pair, determine tunnels for which the downstream MTED is to serve as an exit device and configure the tunnels to deliver the traffic. Lower network MTEDs of a tunnel may determine whether to transport multicast data for each SG pair such that multicast traffic routed by a corresponding MTED is carried. An MTED may be able to receive, through the tunnel, multicast traffic for one SG pair even after pruning itself for another SG pair.

First claim

What is claimed is:

1. A system for tunneling multicast traffic across a lower-layer network, the system comprising:
at least three multicast tunneling edge devices configured to:
exchange data with each other over the lower-layer network, and
tunnel multicast traffic from an upper-layer network across the lower-layer network, the multicast traffic in the upper-layer network associated with a plurality of different source, group (SG) pairs disposed in the upper-layer network, wherein:

the multicast traffic for the plurality of SG pairs is routed through the upper-layer network towards group members disposed in the upper-layer network using a dense-mode multicast routing protocol,
each SG pair maps to at least one tunnel across the lower-layer network, each tunnel comprising at least one multicast tunneling edge device as an entry endpoint and at least two multicast tunneling edge devices as exit endpoints; and
each multicast tunneling edge device is configured to enable and disable itself as an exit endpoint dependent on whether the multicast tunneling edge device is to forward multicast traffic for an active SG pair.

2. The system of claim 1 , wherein at least one of the multicast tunneling edge devices learns of the active SG pair through a data or control message.

3. The system of claim 1 , wherein:
the multicast traffic for the active SG pair is received across the at least one tunnel.

4. The system of claim 1 , wherein the dense mode routing protocol employed by the upper-layer network includes at least one of:
Protocol-Independent Multicast Dense Mode (PIM-DM),
Distance Vector Multicast Routing Protocol (DVMRP), and
a multicast routing protocol that reactively prunes unneeded branches for distribution of multicast traffic.

5. The system of claim 1 , wherein:
multicast traffic for a particular SG pair is tunneled across the lower-layer by embedding upper-layer multicast data in lower-layer multicast packets, specifying as a destination address of the lower-layer multicast packets a lower-layer group identity (ID) to which a specific SG pair maps; and
the multicast tunneling edge devices are configured to enable themselves as exit endpoints of a tunnel corresponding to the specific SG pair by joining a corresponding lower-layer group corresponding to the specific SG pair, and disable themselves as exit endpoints of the tunnel corresponding to the specific SG pair by leaving the corresponding lower-layer group.

6. The system of claim 1 , wherein:
multicast traffic from the upper-layer network is encrypted for tunneling across the lower-layer network.

7. The system of claim 1 , wherein:
at least one of the multicast tunneling edge devices is configured to act as a multicast router in the upper-layer network for the dense-mode multicast routing protocol.

8. The system of claim 1 , wherein:
at least one of the multicast tunneling edge devices is configured to act as a multicast bridge in the upper-layer network.

9. The system of claim 1 , wherein:
at least one of the multicast tunneling edge devices is configured to learn of the active SG pair through a control message.

10. The system of claim 9 , wherein the control message is one of:
a single message that contains one of:
a list of different SG pairs for multicast traffic, or
a single SG pair for multicast traffic,

a group listing message listing all groups for which a particular source is originating multicast traffic, or
a source listing message listing all sources upstream of an originating router that are originating traffic for a particular group.

11. The system of claim 9 , wherein at least one of:
the control message is unicast, repeated periodically, and carried by one of:
a non-reliable transport mechanism, or
a reliable transport mechanism and the control messages carry only changes in active sources.

12. The system of claim 9 , wherein:
the control message is multicast and repeated periodically.

13. The system of claim 9 , wherein:
the control message acts as at least one of a state refresh or assert message in a Protocol-Independent Multicast Dense Mode (PIM-DM).

14. The system of claim 9 , wherein the control message is at least one of:
sent by another multicast tunneling edge device, and
sent by a router upstream of another multicast tunneling edge device.

15. A multicast tunneling edge device comprising:
a first interface configured to communicate multicast traffic associated with a plurality of different source, group (SG) pairs through tunnels across a lower-layer network;
a second interface configured to communicate multicast traffic associated with the SG pairs through an upper-layer network in which the multicast traffic is routed by a dense-mode multicast routing protocol, and
processing circuitry configured to determine whether to perform, based on a triggering event associated with an SG pair, one of:
operations related to a change in forwarding multicast traffic and transmission of Source Active messages for the SG pair received from the upper-layer network, and
operations related to establishment of lower-layer group memberships on the lower-layer network, the operations including determining whether or not to configure or retain the multicast tunneling edge device as an endpoint of a tunnel across the lower-layer network carrying multicast traffic for the SG pair dependent on whether other Source Active messages for another SG pair are being received.

16. The multicast tunneling edge device of claim 15 , wherein the operations related to a change in forwarding multicast traffic and transmission of Source Active messages for the SG pair received from the upper-layer network comprise one of:
initiating forwarding of multicast traffic for the SG pair and transmission of the Source Active messages for the SG pair to potential exit multicast tunneling edge devices on the lower-layer network, the Source Active messages configured to inform each potential exit multicast tunneling edge device to configure the potential exit multicast tunneling edge device to receive multicast traffic for the SG pair to be tunneled across the lower-layer network, and
terminating forwarding of the multicast traffic for the SG pair and transmission of the Source Active messages for the SG pair to the potential exit multicast tunneling edge devices on the lower-layer network.

17. The multicast tunneling edge device of claim 15 , wherein the operations related to establishment of lower-layer group memberships on the lower-layer network comprise:
determining whether the other Source Active messages are being received from another multicast tunneling edge device on the lower-layer network for the other SG pair and whether data for the other SG pair is to be forwarded out another link, and one of:
configuring the multicast tunneling edge device as an endpoint of a tunnel across the lower-layer network carrying multicast traffic for the other SG pair in response to determining that the other Source Active messages are being received from the other multicast tunneling edge device across the lower-layer network for the other SG pair and data for the other SG pair is to be forwarded out the other link onto the upper-layer network, and
determining whether the multicast tunneling edge device is to remain the endpoint of the tunnel carrying multicast traffic for the other SG pair in response to determining that the other Source Active messages are no longer being received from the other multicast tunneling edge device on the multilayer link for any other SG pair mapping to the

Assignees

• Raytheon Bbn Technologies Corp

Inventors

• Weinstein Joseph Jacob

Classifications

• H04L12/4633

  Interconnection of networks using encapsulation techniques, e.g. tunneling · CPC title

• H04L45/16 Primary

  Multipoint routing · CPC title